HomeMy WebLinkAboutCosmos Hills Feasibility study 04-18-2014
Cosmos Hills Hydro Feasibility
AEA Grant Agreement No. 2195413
Feasibility Study and
Conceptual Design Report
Prepared for:
Alaska Village Electric Cooperative (AVEC)
April 18, 2014
Prepared by:
WHPacific, Inc.
300 W. 31st. Avenue
Anchorage, AK 99503
Title: Feasibility Study and Conceptual Design Report
Project: Cosmos Hills Hydro Feasibility
AEA Grant Agreement 2195413
Prepared for: Mr. Steven Gilbert, Manager
Projects Development and Key Accounts
Alaska Village Electric Cooperative
4831 Eagle Street
Anchorage, Alaska 99503
In collaboration with
Mr. Sonny Adams, Project Manager
NANA Regional Corporation
1001 East Benson Boulevard
Anchorage, Alaska 99508
Date: April 18, 2014
Submitted By: WHPacific
300 West 31st Avenue
Anchorage, Alaska 99503
Prepared By: Mr. Steven E. Coleman, PE Mr. Daniel Hertrich, PE
Table of Contents
Feasibility Study and Conceptual Design Report Page i
Cosmos Hills Hydro Feasibility
Executive Summary ............................................................................................................. vii
Village Information ............................................................................................................ viii
Project Information .............................................................................................................. ix
Constructability ......................................................................................................................x
Economic Analysis ............................................................................................................... xi
Recommended Project ........................................................................................................ xiii
1. Introduction.......................................................................................................................1
1.1 Purpose of Report .........................................................................................................1
1.2 Need for Project ............................................................................................................1
2. Project Background ..........................................................................................................3
2.1 General ..........................................................................................................................3
2.2 AEA Renewable Energy Grant .....................................................................................3
2.3 Completed Reports / Studies ........................................................................................3
3. Cosmos Hills Area Background Information...............................................................15
3.1 Location and Access ...................................................................................................15
3.2 Population and Economy ............................................................................................16
3.3 Culture and History .....................................................................................................17
3.4 Local Governments .....................................................................................................17
3.5 Recreation and Subsistence ........................................................................................18
3.6 Infrastructure ...............................................................................................................19
3.7 Land Ownership and Right-of-Way ...........................................................................20
3.8 Topography and Soils .................................................................................................21
3.9 Gravel Sources ............................................................................................................21
3.10 Climate ........................................................................................................................22
3.11 Natural Hazards ..........................................................................................................22
4. Cosmos Hills Hydrology .................................................................................................23
4.1 Hydrology Overview ..................................................................................................23
4.2 USGS Stream Discharge Data ....................................................................................23
4.3 GWS Stream Discharge Data .....................................................................................26
4.4 Data Analysis ..............................................................................................................27
4.5 Recommended Stream Discharge Data for Developmental Analysis ........................29
4.6 GWS Air and Water Temperature Data ......................................................................30
5. Existing Diesel Generation and Transmission System ................................................35
5.1 Basic Configuration ....................................................................................................35
5.2 Existing Energy Generation ........................................................................................37
5.3 Existing Energy Market ..............................................................................................39
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Cosmos Hills Hydro Feasibility
6. Alternative Project Descriptions .................................................................................. 45
6.1 Wesley Creek ............................................................................................................. 45
6.2 Dahl Creek ................................................................................................................. 51
6.3 Kogoluktuk River....................................................................................................... 54
6.4 Hydroelectric Capacity Selection .............................................................................. 60
7. Life-Cycle Cost Analysis................................................................................................ 67
7.1 Displaced Diesel Electric Generation ........................................................................ 67
7.2 Project Development Costs ........................................................................................ 67
7.3 Lifecycle Evaluation .................................................................................................. 72
7.4 Project Summary ........................................................................................................ 79
8. Project Development Issues .......................................................................................... 89
8.1 Land Ownership ......................................................................................................... 89
8.2 Permitting ................................................................................................................... 89
8.3 Federal Energy Regulatory Commission (FERC) Requirements .............................. 89
8.4 Fish Habitat ................................................................................................................ 91
8.5 Constructability .......................................................................................................... 92
8.6 Winter Operations ...................................................................................................... 92
9. Recommendations and Conclusions ............................................................................. 95
9.1 Feasible Projects ........................................................................................................ 95
9.2 Recommended Project: Kogoluktuk River Hydroelectric Project ............................. 96
9.3 Next Steps .................................................................................................................. 98
10. References ..................................................................................................................... 101
FIGURES
Figure 1: Project Area Vicinity Map ..................................................................................... 15
Figure 2: Fish Species Collected; Wesley Creek ................................................................... 61
Figure 3: Fish Species Collected; Dahl Creek ....................................................................... 63
Figure 4: Fish Species Collected; Kogoluktuk River ............................................................ 65
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TABLES
Table 3-1: Location Data ........................................................................................................16
Table 3-2: U.S. Census Data and Growth Rates for Kobuk, Shungnak, and Ambler ............17
Table 3-3: Cosmos Hills Area Climate Data ..........................................................................22
Table 4-1: Monthly Flows – Dahl Creek (USGS 15743850 DAHL C
NR KOBUK AK, 11 sq mi Drainage Area *) ......................................................24
Table 4-2: Monthly Flows – Kobuk River (USGS 15744500 KOBUK R
NR KIANA AK, 9520 sq mi Drainage Area *)....................................................25
Table 4-3: Monthly Average of Median Daily Flows used for Modeling ..............................30
Table 5-1: Shungnak Power Generation Units .......................................................................35
Table 5-2: Ambler Power Generation Units ...........................................................................36
Table 5-3: Proposed Ambler Intertie ......................................................................................36
Table 5-4: PCE Electric Demand ...........................................................................................37
Table 5-5: Projected Energy Demand .....................................................................................37
Table 5-6: AVEC Diesel Fuel Deliveries to Ambler, 2004 to 2012 .......................................39
Table 5-7: AVEC Diesel Fuel Deliveries to Shungnak, 2004 to 2012 ...................................39
Table 5-8: Fuel Price Projection Scenarios, Fuel Price in 2013 $/gal ....................................42
Table 5-9: Nonfuel Costs from AVEC 2012 PCE Annual Report .........................................43
Table 6-1: Wesley Creek - Penstock Diameters and Hydraulic Capacity ..............................47
Table 6-2: Dahl Creek - Penstock Diameters and Hydraulic Capacity ..................................52
Table 6-3: Hydro Project Detailed Configuration ..................................................................60
Table 7-1: Wesley Creek Project - Conceptual-Level Development Cost Estimate ..............68
Table 7-2: Dahl Creek Project - Conceptual-Level Development Cost Estimate ..................69
Table 7-3: Combined Wesley Creek / Dahl Creek Project - Conceptual-Level
Development Cost Estimate .................................................................................70
Table 7-4: Kogoluktuk River Project - Conceptual-Level Development Cost Estimate ........71
Table 7-5: Operations and Maintenance Costs .......................................................................72
Table 7-6: Net Present Value of Hydro Project Benefits, Millions of 2013 $........................75
Table 7-7: Net Present Value of Hydro Project Cost, Millions of 2013 $ ..............................75
Table 7-8: Hydro Project Benefit to Cost Ratios (Electricity Only) ......................................76
Table 7-9: Net Present Cost of Electric Generation, Millions of 2013 $ ...............................76
Table 7-10: Net Present Cost of Electric Generation, Millions of 2013 $ .............................77
Table 7-11: Net Present Value of Using “Excess” Electricity for Heat,
Millions of 2013 $ ................................................................................................78
Table 7-12: Hydro Project Benefit to Cost Ratios (including the Heat Value
of Electricity) ........................................................................................................79
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Cosmos Hills Hydro Feasibility
EXHIBITS
Exhibit 4-1: Daily Flow Chart for USGS 15743850 DAHL C NR KOBUK AK ................. 24
Exhibit 4-2: Daily Flow Chart for USGS 157444500 KOBUK R NR KIANA AK ............. 25
Exhibit 4-3: Kobuk River Annual Discharge Trend .............................................................. 26
Exhibit 4-4: Chart Comparing the USGS and G-W Scientific (Lilly)
Dahl Creek Discharge Data ................................................................................. 28
Exhibit 4-5: Chart of Cosmos Hills Region Unit Discharge Data, 2010 Water Year ........... 28
Exhibit 4-6: Wesley Creek, Hourly Air Temperature Data ................................................... 31
Exhibit 4-7: Wesley Creek, Hourly Water Temperature Data ............................................... 31
Exhibit 4-8: Dahl Creek, Hourly Air Temperature Data ....................................................... 32
Exhibit 4-9: Dahl Creek, Hourly Water Temperature Data ................................................... 32
Exhibit 4-10: Kogoluktuk River, Hourly Air Temperature Data ........................................... 33
Exhibit 4-11: Kogoluktuk River, Hourly Water Temperature Data ...................................... 33
Exhibit 5-1: Projected Electric Generation for Ambler and Shungnak ................................. 38
Exhibit 5-2: Daily Power Demand ......................................................................................... 38
Exhibit 5-3: Ambler Fuel Pricing Projections ....................................................................... 42
Exhibit 6-1: Wesley Creek Hydro Energy Potential .............................................................. 50
Exhibit 6-2: Dahl Creek Hydro Energy Potential .................................................................. 54
Exhibit 6-3: Kogoluktuk River Hydro Energy Potential ....................................................... 59
Exhibit 7-1: Wesley Creek Hydroelectric Project Summary ................................................. 80
Exhibit 7-2: Dahl Creek Hydroelectric Project Summary ..................................................... 82
Exhibit 7-3: Wesley + Dahl Hydroelectric Project Summary ............................................... 84
Exhibit 7-4: Kogoluktuk River Hydroelectric Project Summary .......................................... 86
PHOTOS
Photo 6-1: Wesley Creek Road and Gaging Station at Bridge .............................................. 47
Photo 6-2: A Small Single Jet Pelton Turbine ....................................................................... 49
Photo 6-3: A Small Turgo Runner, Deflector Plate, and Nozzle ........................................... 53
Photo 6-4: Kogoluktuk Intake Site with Obstructing Cliff Downstream .............................. 56
Photo 6-5: Oblique Aerial of Kogoluktuk Penstock Route ................................................... 57
Photo 6-6: Large Kaplan Runner with Adjustable Stainless Steel Blades ............................. 58
APPENDICES
A Wesley Creek Conceptual Design
B Dahl Creek Conceptual Design
C Kogoluktuk River Conceptual Design
D Conceptual-Level Construction Cost Estimates
Summary of Abbreviations and Acronyms
Feasibility Study and Conceptual Design Report Page v
Cosmos Hills Hydro Feasibility
AASHTO American Association of State Highway and Transportation Officials
ADF&G Alaska Department of Fish and Game
ADNR Alaska Department of Natural Resources
ADOT&PF Alaska Department of Transportation and Public Facilities
ADT Average daily traffic
AEA Alaska Energy Authority
AHRS Alaska Heritage Resource Survey
AK Alaska
ANCSA Alaska Native Claims Settlement Act
ANTHC Alaska Native Tribal Health Consortium
ATV All-terrain vehicle
AVEC Alaska Village Electric Cooperative
BIA Bureau of Indian Affairs
BLM Bureau of Land Management
CFR Code of Federal Regulations
cfs Cubic feet per second
DCCED Department of Commerce, Community, and Economic Development
DCRA Division of Community and Regional Affairs
DEM Digital elevation model
E East
EA Environmental Assessment
ESE East-southeast
°F Degrees Fahrenheit
FERC Federal Energy Regulatory Commission
FHWA Federal Highway Administration
FONSI Finding of No Significant Impact
fps Feet per second
FRP Fiberglass reinforced plastic
ft Feet
GDVLVLR AASHTO’s “Guidelines for Geometric Design of Very Low-Volume Local Roads”
GWS Geo-Watersheds Scientific
H Horizontal
HDM ADOT&PF’s “Alaska Highway Drainage Manual”
HDPE High-density polyethylene
ISER University of Alaska Anchorage Institute of Social and Economic Research
IRA Indian Reorganization Act
K Kindergarten
kW Kilowatt
LIDAR Laser imaging detection and ranging
mi. Mile
MIRL Medium intensity runway lighting
N North
N/A Not Applicable
NAB Northwest Arctic Borough
NANA NANA Regional Corporation
Summary of Abbreviations and Acronyms
Feasibility Study and Conceptual Design Report Page vi
Cosmos Hills Hydro Feasibility
NFS Non-frost susceptible
NHS National Highway System
NIHA Northwest Inupiat Housing Authority
NWABSD Northwest Arctic Borough School District
O&M Operation and maintenance
PCE Alaska Energy Authority Power Cost Equalization Program
PCM ADOT&PF’s “Alaska Preconstruction Manual”
P.E. Professional Engineer
PGDHS AASHTO’s “A Policy on Geometric Design of Highways and Street”
PLSS Public Land Survey System
P.O. Post Office
R Range
RCA Regulatory Commission of Alaska
ROW Right-of-way
S South
SHPO State Historic Preservation Office
sq. mi. Square mile
T Township
U.S. United States
USACE United States Army Corp of Engineers
USGS United States Geological Survey
USS United States Survey
V Vertical
vpd Vehicles per day
W West
WNW West-northwest
WRCC Western Regional Climate Center
% Percent
$ U.S. Dollars
° Degree
‘ Minute
“ Second
Executive Summary
Feasibility Study and Conceptual Design Report Page vii
Cosmos Hills Hydro Feasibility
EXECUTIVE SUMMARY
This report provides economic and technical feasibility conclusions for hydro projects in the
Upper Kobuk Valley that would serve the villages of Ambler, Shungnak, and Kobuk.
The Alaska Village Electric Cooperative (AVEC) is the electric utility for Upper Kobuk
Valley villages. The utility has been interested in assessing hydropower potential in the
region for many years. In fact, a limited number of hydropower studies have been
performed in the area since 1979.
Ambler, Shungnak, and Kobuk are small villages located on the Kobuk River. These
villages are accessible by river and air; no roads connect them. The villages are adjacent to
the Cosmos Hills, where three potential hydroelectric projects are located: Wesley Creek,
Dahl Creek, and Kogoluktuk River Hydroelectric Projects.
Kobuk is the closest village to the project sites. Kobuk is approximately 7 miles east-
northeast of Shungnak, 30 miles east-southeast of Ambler, 150 miles east of Kotzebue.
Project Area Vicinity Map
The project is funded by a grant from the Alaska Energy Authority. This report is the
culmination of a project begun in 2009 that includes nine previous reports. This report
Executive Summary
Feasibility Study and Conceptual Design Report Page viii
Cosmos Hills Hydro Feasibility
provides a conceptual design for three potential hydropower projects. It provides economic
and technical feasibility analysis and recommends a single project for further study.
Village Information
According to the 2010 census, the region has a population of 671, of which 151 live in
Kobuk, 262 in Shungnak, and 258 in Ambler. At the time of the census, the population was
between 85% and 95% Native. The median household incomes of Kobuk, Shungnak, and
Ambler were reported to be $31,300, $47,700, and $57,600, respectively. Most residents
supplement their income with subsistence activities.
The villages all have federally recognized tribes governed by Tribal Councils. All three
communities also have City governments. Kobuk, Shungnak, and Ambler were
incorporated as second class cities within the Northwest Arctic Borough in 1973, 1967, and
1971. Native residents of the villages are also represented by their regional Native
Corporation, NANA Regional Corporation (NANA).
Electric service is provided by AVEC. Kobuk and Shungnak are connected by a 7-mile
intertie run by the Kobuk Valley Electric Company. Electric energy for Kobuk is produced
at the diesel generation plant in Shungnak and delivered through the existing Shungnak-
Kobuk intertie, which was constructed about 30 years ago (AVEC Kobuk). Ambler has its
own electric generation plant. Most homes in the villages are connected to the community’s
electrical distribution system.
Between 2008 and 2012, annual electric energy generated at the Shungnak plant, which also
serves Kobuk, averaged 1,534,950 kWh/year. The same annual average for Ambler was
1,294,784 kWh/year. During that time, electric production has fluctuated somewhat, but on
average it has increased by a region-wide average of 1.4%/year; 1.8%/year for Shungnak
and 0.9% for Ambler.
For many years, fuel has typically been delivered by barge to Ambler and Shungnak. Over
the last decade, the Kobuk River has, with increasing frequency, been too low to
accommodate barges, and fuel has been delivered by air at a significant additional cost.
From 2004 to 2012, Ambler has been forced to rely on air delivery 24% of the time and
Shungnak, located further upriver, has received 57% of its fuel deliveries by air. Locals are
increasingly observing shallow, difficult river conditions at the villages.
Air delivery of fuel is significantly more expensive than barge delivery. Fuel delivered by
barge between 2004 and 2012, has averaged $3.59/gallon at Ambler and $3.13/gallon at
Shungnak. (The reason barge-delivered fuel appears cheaper at Shungnak is that during the
most expensive barge years, Shungnak received only air-delivered fuel.) Air-delivered fuel
has averaged $5.60/gallon for Ambler and $5.79/gallon for Shungnak for that time period.
Both villages are currently receiving 100% of their fuel by airplane at a cost of $7.75/gallon
at Ambler and $7.00/gallon at Shungnak. Residents propose a variety of reasons for the
increasing difficulty of getting barges to the communities, but they are clear that the problem
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Cosmos Hills Hydro Feasibility
is getting worse. In the future, AVEC does not expect to receive barges at Shungnak, and
expects to require air delivery to Ambler approximately half the time.
Fuel oil is the primary heat source for village residents and commercial facilities. It is
selling for $7/gallon in Ambler and $10/gallon in Shungnak.
Project Information
The three hydroelectric projects being considered are all run-of-the river projects. Two of
them, the Wesley Creek and Dahl Creek projects, are on relatively small creeks. During
much of the year, the projects’ electric output would be almost completely used by the
villages when they begin operation. The third project, Kogoluktuk River, is much larger, as
it is on a much larger river. The project is large enough to generate electricity surplus to
current village needs. The surplus electricity could be used for heat, to supply village
growth, or for economic opportunities that develop in the region.
The economic analysis in the report includes 12 different fuel, intertie, and environmental
scenarios. A comparison of one representative scenario is listed below to help describe the
projects and illustrate the differences between them. The scenario below assumes that an
intertie is constructed between Ambler and Shungnak and so links the electric loads for all
three villages. It also assumes an AVEC price forecast for fuel, and that agencies require
some water to by-pass the intake to maintain fish habitat in the section of the river between
the intake and tailrace.
Table E-1: Project Information
Wesley Creek Dahl Creek Kogoluktuk
River
Drainage Basin (sq. miles) 5.24 8.50 423.5
Average Annual Streamflow (cfs)1 9.8 15.9 558
Design Flow (cfs) 15 16 170
Static Head (feet) 292 257 64
Installed Hydro Capacity (kW) 260 230 690
Penstock Length (feet) 7,750 9,000 4,300
Annual Energy Potential (kWh) 1,170,000 1,310,000 5,410,000
Hydro penetration in Year 0 36% 41% 96%
Development Cost (million $) $13,619,000 $15,247,000 $38,660,000
Annual O&M cost $68,100 $76,200 $193,300
In the table above, the measurement location for the drainage basin and streamflow is the
hydro’s intake site. Hydro penetration means the proportion of the village’s annual electric
needs that the hydro supplies when the project begins operation. The reason that the
penetration is not 100% is that none of the projects supply all of the villages’ electric needs
during the winter when streamflow is lowest and village electric demand is highest.
1 Wesley and Dahl Creek streamflow based on USGS Dahl Creek reporting. Kogoluktuk River streamflow
based on USGS Kobuk reporting.
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Cosmos Hills Hydro Feasibility
Constructability
All of the projects appear technically feasible to construct. None appear to have unusual
land, permitting, or construction issues.
• Land Ownership Issues. There are no significant ownership or land use issues with
the potential hydro projects. Each would be on land owned by NANA Regional
Corporation. All of the access routes are on NANA-owned land. None affect any
private parcels or mining claims, though the potential road to the Kogoluktuk would
need to be routed to avoid the Dahl Creek runway and a Native Allotment.
• Permitting/FERC/Environmental Issues. None of the projects appear to have
serious permitting/FERC/environmental issues. Each of the projects is likely exempt
from the FERC process, based on previous studies in the area. None of the projects
has obvious permitting pitfalls, except that the extent of required environmental
flows remains to be determined. These flows have a significant effect on the
projects’ benefits. Determination of required environmental flows typically occurs
during permitting and final design.
• Constructability. None of the projects have unusual constructability issues. The
Wesley and Dahl projects should have a straight forward construction process.
Access to much of the Wesley project already exists. Primitive access exists to the
Dahl site. The Kogoluktuk would be a little more difficult, because a six-mile access
road will need to be constructed before the project can begin construction. In
addition, the penstock route will require blasting in steep terrain. The increased cost
for this construction is included in the Kogoluktuk’s construction estimate.
Otherwise, this project also does not present unusual constructability issues.
• Sensitivity to Hydrologic Changes. The economic analysis and power generation
estimates for the three projects are based on the daily median streamflow values
calculated from the USGS Dahl Creek and Kobuk River. The daily median is below
average and is the most appropriate measure for run of river projects. Because
Wesley and Dahl projects use most of the flow in the respective creeks, these two
projects are more susceptible to hydrologic fluctuations. In dry years, they would
produce less power. In wet years, possibly more.
The Kogoluktuk project is much less sensitive to changes in hydrology. Because this
project uses a small amount of a large flow, it is not very sensitive to dry years and
has a hydraulic advantage in reducing the amount of debris and sediment diverted
into the intake. In addition, wet years would have little effect on the electricity
output. The Kogoluktuk’s power output and economic conclusions are therefore
somewhat more reliable than the other two projects.
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Cosmos Hills Hydro Feasibility
Economic Analysis
The report analyzes 12 economic scenarios for the three projects. It analyzes them with and
without an intertie between Ambler and Shungnak (i.e., with a combined 3-village electric
load, or supplying only the Shungnak/Kobuk load). While the economic analysis includes
intertie and no-intertie scenarios, the intertie has significant positive benefits. In fact, the
intertie is economically advantageous even if the hydro projects are not constructed. For
that reason, the project team expects that the intertie will be constructed whether or not the
hydro projects are built.
The economic analysis uses three fuel price scenarios. Two of them are taken from an
Institute from Economic Research report (ISER, 2012). ISER prepares fuel price
projections for over 150 Alaska villages. The two fuel price scenarios used in the economic
analysis are described as ISER Medium fuel case, and ISER High fuel case. Because these
two fuel price scenarios are based on past practices, they under-predict future fuel prices due
to the unfortunate but increasing frequency of air delivery. For that reason, the report also
uses a fuel price projection that includes AVEC’s expectation of future air delivery: a
forecast of 50% air delivery in Ambler and 100% air delivery in Shungnak.
The final variable in the economic scenarios is environmental flows. Environmental flows
are streamflow that the government agencies require to bypass the hydroelectric intake to
maintain certain streamflow in the section of the river between the intake and tailrace. The
greater the environmental flow, the less water available to produce electricity, especially
during periods of low flow, as in winter. Unfortunately, the actual agency-required
environmental flows will not be known until permitting is finished. Agencies could require
a lower volume than the economic model assumes, or possibly a higher volume. It is even
possible that if appropriate mitigation were found, no environmental flow would be
required. The economic analysis used two environmental flow scenarios: with and without a
required flow.
Other economic assumptions include:
• 2013 Dollars. All numbers are reported in 2013 dollars.
• Discount Rate. A discount rate of 2.5% was selected to discount future benefits to
2013 dollars. The selection of the discount rate is based on the recently completed
Southeast Integrated Resource Plan prepared by Black and Veatch for AEA.
• Term of Analysis. The term of analysis is 50 years, consistent with other AEA hydro
analyses.
• Load Growth. The analysis assumes a 1% continuous load growth for the villages.
This growth is less than the load growth that has occurred in the village in the last
five years.
A greater list of economic assumptions is given in the body of the report. Using these
economic assumptions, Table E-2 shows the Benefit/Cost Ratios for six of the twelve
economic scenarios analyzed in the report. For simplicity, this executive summary does not
show the scenarios without the Ambler-Shungnak Intertie. All 12 scenarios are listed in the
body of the report.
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Feasibility Study and Conceptual Design Report Page xii
Cosmos Hills Hydro Feasibility
Table E-2: Hydro Project Benefit to Cost Ratios
Fuel Case Environmental
Flow Intertie Wesley Dahl Kogoluktuk
ISER Medium Fuel Case No Yes 1.06 1.05 1.13
ISER High Fuel Case No Yes 1.43 1.42 1.52
AVEC Fuel Case No Yes 1.47 1.46 1.55
ISER Medium Fuel Case Yes Yes 0.94 0.92 0.91
ISER High Fuel Case Yes Yes 1.28 1.24 1.23
AVEC Fuel Case Yes Yes 1.31 1.27 1.25
The table shows that a hydro project is the best alternative for 5 of the 6 scenarios shown.
The only scenario where diesel remains the best alternative is for the ISER Medium fuel
case with required environmental flows). 2
The table also shows the importance of environmental flows. Any environmental flows
decrease Benefit/Cost ratios. This conclusion is true even for scenarios where the project
remains economically viable with environmental flows. Unfortunately, the actual agency-
required environmental flows will not be known until permitting is finished. Agencies could
require a lower volume than the economic model assumes, or possibly a higher volume. It is
even possible that if appropriate mitigation were found, no environmental flow would be
required.
Table E-2 shows Benefit/Cost Ratios without assigning any value for the heating potential of
surplus electricity. During the flows of spring, summer, and fall, the Kogoluktuk project
produces electricity that is surplus to the three-village electric demand. To a much lesser
extent, the other projects do as well. The Benefit/Cost Ratios in Table E-2 assume that the
surplus electricity has no value.
Fortunately, the electricity not needed to supply the village electric demand has a value. It
can be used to displace heating oil used to heat water for the village washeterias or for
sewer/water projects. In addition it could provide for space-heat for community facilities or
even residences. In each of these cases, using the surplus electricity for heat would displace
fuel oil.
Table E-3 shows Benefit/Cost ratios including a value for this surplus electricity. It assumes
a heating oil cost escalating at the rate of the respective fuel oil case.3 It also limits
electricity as heat based on 50% of the demand created by average heating degree days in
the villages.
2 The results for the scenarios that are not shown - the scenarios without an intertie - are similar to the results in
Table E-2 in that a hydro project is preferred in five of the six scenarios without an intertie (all except the ISER
Medium Fuel case). However, with the small, non-intertied loads, the preferred project is the Dahl or Wesley
project.
3 Currently (2013), fuel oil is selling for $10/gallon in Shungnak, and $7/gallon in Ambler.
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Feasibility Study and Conceptual Design Report Page xiii
Cosmos Hills Hydro Feasibility
Table E-3: Hydro Project Benefit to Cost Ratios, including the Heat Value of Electricity
Fuel Case Environmental
Flow Intertie Wesley Dahl Kogoluktuk
ISER Medium Fuel Case No Yes 1.03 1.01 1.22
ISER High Fuel Case No Yes 1.39 1.37 1.64
AVEC Fuel Case No Yes 1.42 1.41 1.65
ISER Medium Fuel Case Yes Yes 0.93 0.90 1.00
ISER High Fuel Case Yes Yes 1.26 1.21 1.35
AVEC Fuel Case Yes Yes 1.29 1.24 1.35
The table shows that the heat value of this otherwise excess electricity has significant
economic value. Benefit/Cost Ratios for the Kogoluktuk project are much higher in Table
E-3 than in E-2.
The table shows value of the excess energy potential of the Kogoluktuk when the heat value
of “surplus” electricity included.
Recommended Project
The purpose of the conceptual design and feasibility study is to produce a conceptual design
for the hydroelectric projects, and to recommend a single project to go forward to detailed
design and permitting. Conceptual designs are provided in appendices to the full report. On
the basis of the economic analysis including the value of “surplus” electricity used for heat,
and for other policy reasons explained in the full report, this report recommends that the
Kogoluktuk Project go forward to detailed design and permitting.
Executive Summary
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Section 1
Introduction
Feasibility Study and Conceptual Design Report Page 1
Cosmos Hills Hydro Feasibility
1. INTRODUCTION
1.1 Purpose of Report
This Feasibility Study and Conceptual Design Report is the culmination of the work
performed under the Alaska Village Electric Cooperative’s (AVEC) Renewable Energy
Grant from the Alaska Energy Authority (AEA). AVEC was awarded this grant to evaluate
hydropower resources in the Cosmos Hills region. The grant project title is “Cosmos Hills
Hydro Feasibility.”
This report builds on previous tasks that were completed as part of the grant and evaluates
the feasibility of potential hydroelectric projects in the Cosmos Hills area near Kobuk,
Alaska. This report will be used as the basis for completing future grant applications to
proceed towards the design and construction of a hydroelectric project.
The grant states that “the final outcome from this grant will consist of a feasibility level
report and a conceptual design report.” This report satisfies that requirement.
1.2 Need for Project
The villages of Kobuk, Shungnak, and Ambler do not have access to the electrical grid, so
all power must be produced locally. Diesel fuel is the primary source of heat and power
generation for these communities. Because of the difficult logistics and the need for on-site
fuel storage, fuel costs are extremely high. This region has some of the highest prices in the
nation for electricity.
Besides stabilizing energy costs, a hydro project would have a significant environmental
benefit resulting from the reduced potential for spilled fuels during transport, storage, and
use. Currently barges are having difficulty navigating the Kobuk River to get to these
villages. Air transport is the only other alternative to deliver fuel to these villages. The
chance of an incident during delivery is high and the consequences severe.
NANA Regional Corporation (NANA) is very interested in exploring renewable energy
resources in their region and has been a partner on a number of the individual studies
utilized in this project. NANA will continue to be a partner and strong advocate for this
project, as one of their long-term visions is to be 50% reliant on regionally available energy
resources by the year 2050.
Section 1
Introduction
Feasibility Study and Conceptual Design Report Page 2
Cosmos Hills Hydro Feasibility
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Section 2
Project Background
Feasibility Study and Conceptual Design Report Page 3
Cosmos Hills Hydro Feasibility
2. PROJECT BACKGROUND
2.1 General
AVEC has been interested in assessing the hydropower potential in the Kobuk River Valley
for a number of years. Since 1979, a limited number of hydropower studies have been
performed in the area. This project was designed to determine if hydropower in the Kobuk
River Valley, specifically in the Cosmos Hills, is a viable and feasible option for AVEC to
pursue. NANA is also very interested in exploring renewable energy resources in their
region and has been a partner on a number of the individual studies utilized in this project.
2.2 AEA Renewable Energy Grant
On November 22, 2009, AVEC was awarded a Renewable Energy Grant from AEA to
evaluate hydropower resources in the Cosmos Hills region. The grant project title is
“Cosmos Hills Hydro Feasibility” and the grant agreement number is 2195413.
The Scope of Work states that AVEC “will use these funds to prepare a feasibility study of
the potential hydro resources to serve the villages of Ambler, Shungnak, Kobuk, and Kiana.
The stated goal of the study is “to arrive at no more than a single site for each of the four
villages for further study or for the interconnected market area.” The grant also states that
“the final outcome from this grant will consist of a feasibility level report and a conceptual
design report.”
The various task items included in the grant agreement are:
• Project Start-up and Existing Data Analysis
• Community Outreach / Village Presentations
• Hydrology Study / Stream Gauging
• Surveying and Mapping
• Geotechnical Review
• Field Studies, Environmental Assessment and Permits
• Engineering Design
• Feasibility Study and Conceptual Design Report
2.3 Completed Reports / Studies
The following reports and studies were conducted by WHPacific and/or our subconsultants
as part of this project. A brief summary of each report is provided, below. All of these
reports have been previously delivered to AVEC.
Section 2
Project Background
Feasibility Study and Conceptual Design Report Page 4
Cosmos Hills Hydro Feasibility
2.3.1 Cosmos Hills Hydroelectric Feasibility Study; FERC Requirements and Field
Study Recommendations
This report, prepared by Solstice Alaska Consulting, Inc. (Solstice) and dated March 30,
2010, summarizes the Federal Energy Regulatory Commission (FERC) licensing and
exemption processes for the Cosmos Hills hydroelectric projects.
In 2009, AVEC secured separate preliminary permits from the FERC for developing
hydroelectric projects on the Shungnak and Kogoluktuk Rivers. Both of these projects were
described in the permit as 200- to 250-foot high earth-filled gravity dams spanning the rivers
and impounding large reservoirs. Power generated would be 4 to 5 megawatts each.
The report states that smaller projects on these two rivers could be exempt from the FERC
licensing process. Projects on Jade Creek (near Ambler), Cosmos Hills (near Shungnak),
Dahl Creek (near Kobuk), and Canyon Creek (near Kiana) could also fall under a FERC
exemption from licensing.
Representatives from Solstice met with the FERC and recommended that the following
environmental studies be performed at this phase of work: office-based wetlands
delineation, fisheries and aquatic resources study, and office-based cultural resources study.
The Solstice report also provided a detailed contact list of Federal, state, and local resource
agencies and stakeholders.
2.3.2 Cosmos Hills Hydropower Study: Reconnaissance Report
This report, prepared by WHPacific and dated September 22, 2010, is the first of a series of
documents prepared under this grant. It reviews work completed by others in the past,
updates cost estimates, and re-runs economic analyses. The report also describes each of the
seven sites being investigated, describes potential projects, identifies project benefits and
risks, describes the public outreach efforts undertaken, and provides recommendations on
sites to be investigated further.
The Dahl Creek, Wesley Creek, Cosmos Creek, and Kogoluktuk River run-of-river sites
were recommended for further study. These projects have attractive projected energy
outputs and relatively close proximity to electric load and existing infrastructure. The
Kogoluktuk River site also has the potential to produce hydropower for more than half the
year.
The Shungnak River run-of-river, Jade Creek – East Fork, and Canyon Creek sites were not
recommended for further study. These projects have limited accessibility and are relatively
long distances from community electric loads. The Jade Creek – East Fork and Canyon
Creek sites were also estimated to have small generation capacities.
The report has six appendices. Appendix A includes the proposed summer 2010 work plans
for the following tasks:
Section 2
Project Background
Feasibility Study and Conceptual Design Report Page 5
Cosmos Hills Hydro Feasibility
• Hydro-Electric Hydrologic Network Project (by Geo-Watersheds Scientific)
• Orthophoto and LIDAR Mapping (by AeroMetric)
• Preliminary Geotechnical Review and Hazards Analysis (by Golder Associates)
• Fish and Fish Habitat Survey (by WHPacific)
• Wetlands Study (by WHPacific)
• Cultural Resources Office Study (by WHPacific)
Appendix B contains the Public Meeting minutes from meetings in Ambler, Shungnak, and
Kobuk.
Appendix C contains Solstice’s FERC report, described above.
Appendix D contains Preliminary Project Cost Estimate data from NANA WorleyParsons.
Appendix E contains the Preliminary Permits issued by FERC.
Appendix F contains data and reports from the HOMER Computer Models for the Dahl
Creek and Cosmos Creek sites.
2.3.3 Cosmos Hills Hydropower Study: Summer-Fall 2010 Report
In July 2010, AVEC decided to proceed with further study on Cosmos Creek, Wesley Creek,
Dahl Creek, and the Kogoluktuk River during the summer/fall 2010 fieldwork season. This
report, prepared by WHPacific and dated November 18, 2010, provides a summary of the
studies and work completed during summer/fall 2010. Appendices A through E contain the
actual reports and work products.
Hydrology:
Climate/hydrological stations were installed at all four sites in August 2010. Four hilltop
radio repeaters were also installed at that time. Since 1986, the U.S. Geological Survey
(USGS) has operated a stream gauge on lower Dahl Creek, near the airstrip. Data and
records from this existing station will be used along with data collected from the four new
hydrologic stations for hydrological analysis of the potential hydropower sites.
Water depth is being collected at each climate/hydrologic station and utilized with discharge
measurements performed by team members to develop stage/discharge relationships.
Additional data is being collected to evaluate climate and river conditions, including air
temperature, summer precipitation, camera images, and water temperature.
Geo-Watersheds Scientific, Brailey Hydrologic, and EEInternet are the project partners and
have started the Cosmos Hills hydroelectric hydrologic network website:
http://www.cosmoshydro.org. The website shares real-time data and webcam images from
the stream gauges and mini weather stations.
Section 2
Project Background
Feasibility Study and Conceptual Design Report Page 6
Cosmos Hills Hydro Feasibility
Aerial Photography and LIDAR Mapping:
AeroMetric made two flights over the Cosmos Hills hydroelectric project study areas – one
on August 24, 2010 for aerial photography, and another on September 14, 2010 for LIDAR
mapping. The following was provided for each site:
• Bare Earth Digital Elevation Model (DEM) data in ASCII format (from LIDAR)
• One-foot contour interval topographic maps in AutoCAD format (from LIDAR)
• 0.5-foot pixel resolution color digital orthophotos in .tiff format
Appendix A contains figures showing this data.
Wetlands Delineation:
A field reconnaissance was conducted by WHPacific between July 26 and August 2, 2010 to
determine wetland types. Field studies were conducted along Cosmos Creek, Dahl Creek,
and Wesley Creek. Complete and detailed field delineation will not be conducted until a
final project site is selected and the preliminary engineering is completed.
This study, entitled Reconnaissance Report: Wetlands and Other Waters of the United
States; Cosmos Hills, Kobuk River Valley, Alaska, provides data and mapping that identifies
and locates stream channels and wetlands at reconnaissance-level accuracy and characterizes
wetlands habitats that will be useful in the planning and selection process to determine a
preferred project site. Ordinary High Water Line along the streams was also identified in
several locations. Data was collected on adjacent riparian plant communities, channel and
floodplain morphology, and topography. The wetland polygons were digitized and labeled
according to the U.S. Fish and Wildlife Service’s Cowardin classification system and
mapped on an aerial photograph base.
Appendix B contains the full report, dated November 5, 2010, by WHPacific.
Fisheries and Aquatic Resources Study:
A reconnaissance-level fisheries survey was conducted by WHPacific between July 26 and
August 2, 2010 to determine general fish abundances, habit characteristics, and water
quality. The surveys were conducted on nine separate sample reaches within the Cosmos
Creek, Dahl Creek, and Wesley Creek drainages.
Dolly Varden were collected at all nine sample reaches and slimy sculpins were collected at
four of the reaches. Fish abundance was found to be highest in Dahl Creek, followed by
Wesley Creek, and then Cosmos Creek. Pools associated with high velocity cascades
yielded the largest number of fish. These habitats were common in Wesley Creek and Dahl
Creek.
The dominant stream substrates in the lower reaches of Wesley and Cosmos Creeks were
gravels and cobbles. The substrates in the lower reaches of Dahl Creek, the middle reaches
of Wesley and Dahl Creeks, and the upper reaches of Wesley and Cosmos Creeks were
cobbles and large boulders.
Section 2
Project Background
Feasibility Study and Conceptual Design Report Page 7
Cosmos Hills Hydro Feasibility
Appendix C contains the full report, titled Reconnaissance Fisheries Report, dated
November 17, 2010, by WHPacific.
Office-Based Cultural Resources Study:
An office study of the cultural and historical features within the Cosmos Creek, Wesley
Creek, and Dahl Creek project areas was conducted by WHPacific in fall 2010. To date,
there have been few professional archaeological surveys performed in the Cosmos Hills and
there are few known cultural sites.
Some of the transportation routes into the Cosmos Hills, as well as other historic sites, such
as the mine at Bornite, will need to be evaluated for their historic context. Formal
consultation with the Office of History and Archaeology is likely to mirror the Federal
Section 106 process.
Appendix D contains the full report, titled Cosmos Hills Cultural Resources Office Study,
dated October 18, 2010, by WHPacific.
Geotechnical:
A reconnaissance-level geotechnical exploration was conducted by Golder Associates
between July 26 and July 31, 2010 to observe the surficial geological and geotechnical
conditions along Cosmos Creek, Dahl Creek, and Wesley Creek. The reconnaissance
observations were used in conjunction with existing geological mapping and aerial
photography to conduct a general geological and geotechnical assessment of the project
areas for potential geohazards and general constructability issues.
The general surficial soil conditions were alluvial outwash deposits within established creek
channels. Outside of the defined creek channels, within the lower elevations of the
drainages, the general soil conditions consisted of fine grained alluvial and aeolian deposits
with both unfrozen and potentially frozen (permafrost) soils. At higher elevations along the
creek channels, deposits consisted of fractured and weathered bedrock, potential glacial till,
and colluvium. Adjacent creek channel slopes above the project areas, that were visible
during the reconnaissance, generally did not show signs of recent slope instabilities.
Based on this reconnaissance exploration and study, it was determined that conventional
foundation systems could be considered for both the unfrozen ground areas and potential
frozen ground (permafrost) areas of the project. The facilities should be sited to avoid
permafrost areas where possible. Penstock alignment and drainage topography will pose
foundation geometry and construction challenges at some alignment areas where the creek
channels are well defined with adjacent steep slopes of colluvium and weathered and
fractured rock deposits.
A subsurface soil exploration should be conducted at specific facility locations during the
design development to confirm the surficial observations obtained during the reconnaissance
study.
Section 2
Project Background
Feasibility Study and Conceptual Design Report Page 8
Cosmos Hills Hydro Feasibility
Appendix E contains the full report, titled Geotechnical Reconnaissance Report; Cosmos
Hills Hydroelectric Feasibility Study, dated February 4, 2011, by Golder Associates.
Recommendations in that report for 2011 work included:
• Continue monitoring the stream flows from the Cosmos Hills hydrology network
stations through the end of 2011.
• Conduct the geotechnical, wetlands delineation, and fish habitat fieldwork at the
Kogoluktuk River site in summer 2011.
• Perform the office-based cultural resources study at the Kogoluktuk River site.
• Delay further engineering design, cost estimates, and detailed feasibility analysis
until fall 2011. This will allow a full year’s worth of hydrologic data to be collected.
2.3.4 Cosmos Hills Technical Review and Assessment of Alternatives
This technical memorandum, prepared by WHPacific and dated October 2011, presents the
results of a review and assessment of the work done to date, including hydrology,
hydroelectric modeling, geotechnical, environmental, conceptual engineering, and site
prioritization. Work was performed between July and September 2011 and involved
representatives from AVEC, NANA Regional Corporation, WHPacific, NANA Worley
Parsons, GW Scientific, Golder Associates, and DOWL HKM.
The technical memorandum includes discussions on the following:
• Hydrology and hydroelectric assessment
• Based on the preliminary stage-discharge relationships developed for each site
and elevation data, the four sites were reassessed for the potential power
availability.
• Site prioritization
• Based on the hydrology and hydroelectric reassessments, the sites were
prioritized based on their economic attractiveness.
• The Dahl Creek project was not recommended for further consideration by
AVEC because the lower-than-expected elevation difference between the intake
and powerhouse locations reduces the potential power generation.
• The Cosmos Creek project was not recommended for further consideration by
AVEC because of lower-than-expected flows which reduce the potential power
generation.
• The Wesley Creek and Kogoluktuk River projects were recommended for further
consideration by AVEC.
• Design considerations
• Because not much was known regarding the Kogoluktuk River site, design
considerations were focused primarily on the Wesley Creek project.
• The Wesley Creek intake site is heavily vegetated and has large rock
outcroppings. The geotechnical aspects of the site are the largest risk factors.
Section 2
Project Background
Feasibility Study and Conceptual Design Report Page 9
Cosmos Hills Hydro Feasibility
• The Wesley Creek penstock alignment will follow the access routes as much as
possible.
• The Wesley Creek powerhouse will be located within the creek channel flood
plain where unfrozen sand and gravel deposits are likely. If granular material is
present, then a shallow-depth reinforced concrete foundation system can be used.
If fine-grained material deposits are present, then deeper excavation or a pile
foundation option will need to be considered.
• The Wesley Creek tailrace will need to be designed to minimize impacts to fish
habitat.
• The Wesley Creek site could tie into the existing Shungnak-Kobuk intertie via an
approximately 2-mile transmission line. A small substation would be required at
the tie-in location.
• The Kogoluktuk River site would require a much longer transmission line and
would tie in directly at Kobuk.
• A detailed review and assessment of the required access roads was not done at
this time.
• Preliminary geotechnical investigations
• Wetlands and fisheries summaries
• Sub-regional energy delivery overview
• Discussion and recommendations
2.3.5 Cosmos Hills Hydroelectric Feasibility Study; Geotechnical Investigation
Kogoluktuk River Hydropower Site
This December 14, 2011 report, prepared by WHPacific, contains the geotechnical
assessment of the Kogoluktuk River project site. The reconnaissance-level geotechnical
exploration was conducted by WHPacific between August 30 and September 1, 2011 to
observe the surficial geological and geotechnical conditions along two reaches of the
Kogoluktuk River. The reconnaissance observations included bedrock geologic mapping
and structural mapping, along with shallow soil probing and a review of stream and slope
stability.
The geotechnical investigation showed a variety of landforms associated with two main
bedrock controlled cascade reaches. The bedrock consists of very competent granitic gneiss
with a shallow north dip in both reaches. This bedrock controls upstream and downstream
knickpoints in the river and most of the stream reach is underlain by exposed bedrock. The
most important structural fabric in the bedrock is a shallow north-dipping foliation (20-30
degrees).
Shallow soils are developed both directly on the bedrock and on thin deposits of glacial
outwash and ice-marginal deposits adjacent to the river. The deposits range from well-
sorted cobble and gravel alluvium, to fine-grained sandy outwash, to silty wind-blown loess.
Organic-rich soils are developed directly on bedrock in some shallow wetlands.
Section 2
Project Background
Feasibility Study and Conceptual Design Report Page 10
Cosmos Hills Hydro Feasibility
Five main types of surficial deposits are found within the project area.
• The most extensive type consists of thin alluvial deposits developed on bedrock
ridges. These are well-drained soils in moderately sorted fluvial gravels. They are
typically found on high spots, forming a thin cover over bedrock ridges.
• A large part of the project area is covered by fine-grained, sandy, wind-blown loess.
These soils range from fine sand to silt and are the result of wind-blown deposition
related to ice-marginal glacial sediment.
• Sandy loam soil is developed on fine-grained alluvial deposits adjacent to the river.
• Wetland soils are developed in shallow depressions, typically on bedrock. These
depressions, in many cases, lack internal drainage, and remain saturated throughout
the year.
• Large bedrock slabs form colluvial deposits in some areas of the project area. They
typically occur near bedrock outcrops, but contain large voids and are covered by
moss and spruce trees.
There are some shallow scarps developed along the immediate cutbanks of the river,
especially on outside bends in alluvial reaches. Otherwise, slopes appear stable and there is
no evidence of any recent seismic activity such as fault scarps, slumps, or landslides.
The bedrock at both the proposed intake and powerhouse locations is moderately foliated
granite gneiss that is highly competent.
2.3.6 Cosmos Hills Hydroelectric Pre-Construction Program; Reconnaissance Report:
Fisheries and Water Quality Resources (Aquatic Resources): Kogoluktuk River
Study Area
This April 25, 2012 report, prepared by WHPacific, contains the results of the fisheries
reconnaissance of the Kogoluktuk River project area. The reconnaissance-level fisheries
survey was conducted by WHPacific between August 30 and September 1, 2011 to
determine general fish populations, habit conditions, and water quality parameters. The
surveys were conducted on three sample reaches within the Kogoluktuk River study area.
The study area was centered on the two series of falls and rapids, referred to as the “upper
cataract” and “lower cataract.” The three sample reaches were located downstream of the
“lower cataract,” immediately downstream of the “upper cataract,” and immediately
upstream of the “upper cataract.”
A total of six species of fish were collected in the study area, but only two species were
collected in the middle and upper reaches. Chum salmon, round whitefish, Arctic grayling,
slimy sculpin, northern pike, and Dolly Varden were collected in the lower reach. Only
slimy sculpin and Arctic grayling were collected above the “lower cataract” in the middle
and upper reaches.
It appears that the “lower cataract” prevents upstream passage of fish to the upper river
reaches.
Section 2
Project Background
Feasibility Study and Conceptual Design Report Page 11
Cosmos Hills Hydro Feasibility
2.3.7 Cosmos Hills Hydroelectric Pre-Construction Program; Reconnaissance Report:
Wetlands and Other Waters of the United States: Kogoluktuk River Study Area
This April 5, 2012 report, prepared by WHPacific, contains the results of the wetlands
assessment of the Kogoluktuk River project area. The reconnaissance-level wetlands
investigation was conducted by WHPacific between August 30 and September 1, 2011 to
determine wetland types.
The study provides data and mapping that identify and locate stream channels and wetlands
at reconnaissance-level accuracy and characterize wetlands habitats that will be useful in the
planning and selection process of determining a preferred project site. Ordinary high water
line along the streams was also identified in several locations. Data was collected on
adjacent riparian plant communities, channel and floodplain morphology, and topography.
The wetland polygons were digitized and labeled according to the U.S. Fish and Wildlife
Service’s Cowardin classification system and mapped on an aerial photograph base.
2.3.8 Cosmos Hills Hydrologic Network Installation and Operation, August 2010 –
December 2011
This May 2012 report, prepared by Geo-Watersheds Scientific, describes the hydrologic
monitoring network that was installed to record weather and stream flow data on Cosmos
Creek, Dahl Creek, Wesley Creek, and the Kogoluktuk River. This hydrologic monitoring
network was partially funded by NANA Development Corporation.
The hydrologic monitoring network includes the following:
• Four gauging stations located at the potential intake structures
• A fifth gauging station located at the Upper Kogoluktuk River Falls to gather winter
flow measurements
• Air temperature, relative humidity, and summer precipitation sensors at the four
stream gauging stations
• Time-lapse digital camera at the four gauging stations and the Upper Kogoluktuk
River Falls station
• Four water temperature monitoring stations located at potential tailraces
• Four ridge-top repeaters transmitting data and camera images to an Internet base
station at the Kobuk School
• Air temperature sensors at the four ridge-top repeater sites
The Alaska Department of Natural Resources (ADNR), Alaska Department of Fish and
Game (ADF&G) and multiple Federal regulatory agencies reviewed the project work plan
before field work began and indicated that the approach would meet their criteria for
hydropower-related water-resource investigations.
The installation objectives were to set up the data collection stations, perform stream
surveys, collect discharge measurements and water chemistry data, and observe the general
hydrologic conditions at the sites. The primary purpose of the network and resulting field
Section 2
Project Background
Feasibility Study and Conceptual Design Report Page 12
Cosmos Hills Hydro Feasibility
data collection efforts was to develop stage-discharge rating curves for each of the primary
gauging stations. Secondary objectives included gathering basic water quality
characteristics, such as water temperature and conductivity. Summer precipitation, spring
snowpack measurements, air temperature, and relative humidity data were also collected.
It was determined that Wesley Creek and the Kogoluktuk River hydrology data collection
efforts would continue. The other stations were discontinued in September 2011.
2.3.9 Cosmos Hills Hydroelectric Project; Field Reconnaissance Report
This December 4, 2012 report, prepared by WHPacific, summarized the field
reconnaissance activities that took place between September 26 and September 29, 2012 at
the Wesley Creek and Kogoluktuk River sites. Representatives from WHPacific and Hatch
visited the sites to look specifically at constructability issues and potential locations and/or
routes for access roads, intakes, penstocks, and powerhouses. Office activities included
mapping potential intake, powerhouse, penstock, and access road locations for each site and
updating the energy and benefit analyses.
This field reconnaissance trip and report determined the following:
• The Wesley Creek site would be the easiest and least expensive to construct. It
would have an estimated power output capacity of approximately 350 kW. This site
should continue to be evaluated.
• The Dahl Creek site should be reconsidered as a possible addition to a Wesley Creek
project. Dahl Creek would be a similar project as Wesley Creek and is close to
existing infrastructure. If constructed together as one project, the two projects may
be economical.
• The Lower Kogoluktuk River site was found to be superior to the Upper Kogoluktuk
site. It would have an estimated power output capacity of approximately 890 kW.
While this project is constructible, it is further away from existing infrastructure and
would require a considerably longer access road. The penstock route, between the
intake and powerhouse, will also be difficult to construct and more expensive than
the Wesley Creek site. However, the Lower Kogoluktuk River site will provide
considerably higher power output capacity and will produce power for a longer part
of the year than the Wesley Creek site.
• The Upper Kogoluktuk River site, which consisted of two different development
systems, should be removed from further consideration. The run of river system was
deemed not feasible due to low available head, high construction costs, and poor
geology. The system involving a large dam, with a preliminary capacity of 10 MW,
is too costly for present power needs.
The Cosmos Hills Hydroelectric Project; Field Reconnaissance Report recommended that
the Wesley Creek, Dahl Creek, and Kogoluktuk River sites be investigated further.
Additional LIDAR data should be processed to include the Lower Kogoluktuk River site.
Conceptual-level project designs should be developed, including access road, penstock, and
transmission line routes, and intake and powerhouse structures. Based on the conceptual
Section 2
Project Background
Feasibility Study and Conceptual Design Report Page 13
Cosmos Hills Hydro Feasibility
designs and construction cost estimates, an updated feasibility analysis should be performed,
and a report prepared that recommends a project, if it is found that a feasible project exists.
Section 2
Project Background
Feasibility Study and Conceptual Design Report Page 14
Cosmos Hills Hydro Feasibility
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Section 3
Cosmos Hills Area Background Information
Feasibility Study and Conceptual Design Report Page 15
Cosmos Hills Hydro Feasibility
3. COSMOS HILLS AREA BACKGROUND INFORMATION
3.1 Location and Access
The project areas are located in the Cosmos Hills, near the villages of Kobuk, Shungnak,
and Ambler in the Upper Kobuk River Valley. The Cosmos Hills are an isolated highland at
the southern edge of the Brooks Range and are bounded on the south by the Kobuk River,
on the west by the Shungnak River, on the north by the Ambler Lowlands, and on the east
by the Kogoluktuk River.
Kobuk is the closest village to the project sites. Kobuk is approximately 7 miles east-
northeast of Shungnak, 30 miles east-southeast of Ambler, 150 miles east of Kotzebue, 300
miles west-northwest of Fairbanks, and 460 miles north-northwest of Anchorage.
Figure 1: Project Area Vicinity Map
The Cosmos Hills, as well as the three villages, are located within the Northwest Arctic
Borough and are in the Kotzebue Recording District. The Public Land Survey System
(PLSS) designations and geographical coordinates for the three communities and the project
sites are presented in Table 3-1.
Section 3
Cosmos Hills Area Background Information
Feasibility Study and Conceptual Design Report Page 16
Cosmos Hills Hydro Feasibility
Table 3-1: Location Data
Public Land Survey System (PLSS) Info Geographical Coordinates
Location Section Township Range Meridian Latitude Longitude
Kobuk 3 17N 9E Kateel River 66°55’ N 156°53’ W
Shungnak 9 17N 8E Kateel River 66°53’ N 157°08’ W
Ambler 31 20N 5E Kateel River 67°05’ N 157°51’ W
Wesley Creek
(at Intake) 6 18N 9E Kateel River 66°59’07” N 156°58’43” W
Wesley Creek
(at Powerhouse) 18 18N 9E Kateel River 66°57’55” N 156°59’15” W
Dahl Creek
(at Intake) 10 18N 9E Kateel River 66°58’20” N 156°52’00” W
Dahl Creek
(at Powerhouse) 21 18N 9E Kateel River 66°57’06” N 156°54’02” W
Kogoluktuk River
(at Intake) 8 18N 10E Kateel River 66°58’20” N 156°43’19” W
Kogoluktuk River
(at Powerhouse) 17 18N 10E Kateel River 66°57’52” N 156°43’48” W
Residents in the area use various modes of transportation, depending on the season. Air
transport is the primary means of travel in and out of the area, as well as for shipment of
supplies. Barge services deliver goods to Ambler, but service to Shungnak and Kobuk is
sporadic due to the shallow areas near these villages. Trails and the Kobuk River connect
the villages of Kobuk, Shungnak, and Ambler; there are no roads between these villages.
Depending on the season, snowmachines, all-terrain vehicles (ATVs), or skiffs are the
primary forms of personal transportation within and around the villages, including into the
Cosmos Hills. There are also a limited number of full-size private vehicles.
Portions of the project areas are accessible by dirt roads from Kobuk. The upper portion of
Wesley Creek is accessible by a road that accesses Bornite Mine. The lower portion of Dahl
Creek is accessible by the road to Dahl Creek Airport. The lower portion of Wesley Creek,
the upper portion of Dahl Creek, and the Kogoluktuk River are not accessible by road. The
Kogoluktuk River is navigable by boat up to the lower falls.
3.2 Population and Economy
The population of the area resides primarily in the three villages of Kobuk, Shungnak, and
Ambler. There are seasonal workers in the area associated with the mining industry. At the
time of the 2010 U.S. Census the population of Kobuk, Shungnak, and Ambler was between
85% and 95% Alaska Native. The U.S. Census data and the corresponding rates of growth
or decline are shown in Table 3-2.
Section 3
Cosmos Hills Area Background Information
Feasibility Study and Conceptual Design Report Page 17
Cosmos Hills Hydro Feasibility
Table 3-2: U.S. Census Data and Growth Rates for Kobuk, Shungnak, and Ambler
Community
Census Year Population
10-Year Annual
Rate of Increase
or Decrease
20-Year Annual
Rate of Increase
or Decrease
Kobuk 2010 151 + 3.3% + 4.0%
2000 109 + 4.7%
1990 69
Shungnak 2010 262 + 0.2% + 0.8%
2000 256 + 1.4%
1990 223
Ambler 2010 258 - 1.8% - 0.9%
2000 309 - 0.06%
1990 311
Area-Wide 2010 671 - 0.04% + 0.5%
2000 674 + 1.1%
1990 603
At the time of the 2010 Census, the median household incomes of Kobuk, Shungnak, and
Ambler were reported to be $31,300, $47,700, and $57,600, respectively. Most of the
residents in all three communities supplement their income with subsistence activities.
3.3 Culture and History
The existing community of Kobuk was founded in 1899 as a supply point for mining
activities in the Cosmos Hills to the north. A trading post, school, and Friends mission drew
area residents to the settlement. Because of river erosion and flooding, the village was
relocated in the 1920s to a new site 10 miles downstream, at the present site of Shungnak. A
few people remained in Kobuk. Ambler was permanently settled in 1958 when people from
Shungnak and Kobuk moved downstream because of the variety of fish, wild game, and
spruce trees in the area.
All three villages are Iñupiat Eskimo communities that rely heavily on subsistence hunting,
fishing, and gathering. Residents hunt caribou, moose, black and grizzly bear, Dall sheep,
geese, ducks, ptarmigan, and small game. Furbearers taken include wolf, fox, lynx, and
beaver. Fishing yields salmon, sheefish, graying, whitefish, pike, and trout. Berries are
harvested in the fall. Birch bark is gathered for making baskets.
3.4 Local Governments
The Native Villages of Kobuk, Shungnak, and Ambler are all federally recognized tribes,
governed by Tribal Councils. The Tribal Councils are both traditional councils and
federally recognized governments by virtue of their Indian Reorganization Act (IRA)
Constitutions. Native residents are also represented by their regional corporation, NANA
Regional Corporation (NANA).
Section 3
Cosmos Hills Area Background Information
Feasibility Study and Conceptual Design Report Page 18
Cosmos Hills Hydro Feasibility
All three communities also have City governments. Kobuk, Shungnak, and Ambler were
incorporated as second class cities within the Northwest Arctic Borough in 1973, 1967, and
1971, respectively.
Contact information for the local governments is listed below.
Native Village of Kobuk
P.O. Box 51039
Kobuk, AK 99751
Phone: (907) 948-2203
e-mail: tribeadmin@laugvik.org
President: Rosa Horner
Native Village of Shungnak
P.O. Box 64
Shungnak, AK 99773
Phone: (907) 437-2163
e-mail: roy_sun1@hotmail.com
President: Glenn Douglas
Native Village of Ambler
P.O. Box 47
Ambler, AK 99786
Phone: (907) 445-2238
e-mail:
First Chief:
NANA Regional Corporation
P.O. Box 49
Kotzebue, AK 99752
Phone: (907) 442-3301
President/CEO: Marie Greene
City of Kobuk
P.O. Box 51020
Kobuk, AK 99751
Phone: (907) 948-2217
e-mail: kobukcity@yahoo.com
Mayor: Alex Sheldon
City of Shungnak
P.O. Box 59
Shungnak, AK 99773
Phone: (907) 437-2161
e-mail: Beverelygriest25@hotmail.com
Mayor: Melvin Lee
City of Ambler
P.O. Box 9
Ambler, AK 99786
Phone: (907) 445-2122
e-mail: cityofambler@yahoo.com
Mayor: Wilbur Esenituk
Northwest Arctic Borough
P.O. Box 1110
Kotzebue, AK 99752
Phone: (907) 442-2500
Mayor: Reggie Joule
3.5 Recreation and Subsistence
Recreation and subsistence both involve travel in the region. The bulk of activity is
subsistence and sport hunting and fishing. Travel is primarily by boat during the summer
and by snow machine in the winter along waterways. Locals in Kobuk reported that the
Kogoluktuk River is impassable year round by either snow machine or boat at the lower falls
location. There are a very small number of recreational whitewater rafters that go through
the Upper Kogoluktuk Falls down to the Kobuk River.
Section 3
Cosmos Hills Area Background Information
Feasibility Study and Conceptual Design Report Page 19
Cosmos Hills Hydro Feasibility
3.6 Infrastructure
3.6.1 Housing
The 2010 U.S. Census reported 51 houses in Kobuk (15 of which were vacant), 73 houses in
Shungnak (11 of which were vacant), and 99 houses in Ambler (24 of which were vacant).
The Northwest Inupiat Housing Authority (NIHA) is the native housing authority.
3.6.2 Utilities
Electric service is provided by AVEC. Kobuk and Shungnak are connected with an intertie
run by the Kobuk Valley Electric Company. Most homes are connected to the community’s
electrical distribution system. Fuel oil is the primary heat source.
The City governments own and operate the water treatment and distribution facilities.
Kobuk and Ambler obtain their water from community wells; Shungnak obtains water from
a surface water source. Distribution piping varies between villages. Some residents haul
their water from a central watering point.
The City governments also own and operate the piped sewage collection and treatment
facilities. However, many residents have on-site septic systems or use a “honey bucket”
haul system.
3.6.3 Other Services
Each village has its own school, which include grades K through 12. All are administered
by the Northwest Arctic Borough School District (NWABSD). In fall 2012, the schools in
Kobuk, Shungnak, and Ambler had 45, 83, and 69 students, respectively.
Local health care is provided at clinics located in each village. The clinics are operated by
Maniilaq Association out of Kotzebue. Auxiliary health care is obtained in Kotzebue,
Fairbanks, or Anchorage.
Other structures in the communities include various government, commercial, and public
facilities.
3.6.4 Roads
There are no roads connecting the villages of Kobuk, Shungnak, and Ambler. Each village
has a local road network within the village that extends to the airports and landfills.
Kobuk is connected to a small road network that was constructed by the mining industry to
access the Cosmos Hills. An approximately 13-mile dirt/gravel road connects Kobuk with
the Bornite Mine. Dahl Creek Airport is accessed from the Mine Road. A two-mile road
branches off the Mine Road, approximately one mile west of the Dahl Creek Airport, and
connects with the Kobuk River.
The local roads and trails in the area are generally narrow and unsurfaced. Only a few of the
local roads have been designed to standards and have been surfaced with gravel. There are
Section 3
Cosmos Hills Area Background Information
Feasibility Study and Conceptual Design Report Page 20
Cosmos Hills Hydro Feasibility
many trails throughout the communities and surrounding areas that are simple earth trails
without any type of surfacing material. Most of these roads and trails do not have dedicated
rights-of-way. Only minimal maintenance occurs on the existing roads and trails.
3.6.5 Airports
The State of Alaska owns and maintains the airports in Kobuk, Shungnak, and Ambler.
There is also an airport located at Dahl Creek.
The Kobuk Airport runway is 4,020 feet long and 75 feet wide, oriented in an east-west
direction, and surfaced with gravel. The runway is lit with medium intensity runway lights
(MIRL) and can accommodate DC-6 aircraft. The airport is unattended and fuel is not
available.
The Shungnak Airport runway is 4,000 feet long and 60 feet wide, oriented in an east-west
direction, and surfaced with gravel. The runway is lit with MIRL and can accommodate
DC-6 aircraft. The airport is unattended and fuel is not available.
The Ambler Airport has two runways. The primary runway is 3,000 feet long and 60 feet
wide, oriented in a north-south direction, and surfaced with gravel. The cross-wind runway
is 2,400 feet long and 60 feet wide, oriented in an east-west direction, and surfaced with
gravel. The runways are lit with MIRL. The airport is unattended and fuel is not available.
The Dahl Creek Airport runway is 4,780 feet long and 75 feet wide, oriented in an ESE-
WNW direction, and surfaced with gravel. The runway is marked, but not lit, and can
accommodate Hercules C-130 cargo planes. The airport is unattended and fuel is not
available.
3.6.6 Barge Landings / Boat Landings / Ramps / Docks
Regular barge services are only available as far upriver as Ambler. Shungnak and Kobuk
delivery is hindered by the shallow depth of the Kobuk River at these village sites. These
conditions appear to be worsening, with reliable barge service to Ambler becoming
questionable.
Each village has small boat landings located along the river. There are no docks, so boats
are stored directly on the beach.
3.7 Land Ownership and Right-of-Way
Under Section 12(a) of the Alaska Native Claims Settlement Act (ANCSA), the local village
corporations were each allowed to select the surface rights to land from the federal
government. The regional corporation, NANA, owns and controls the surface and
subsurface rights to these lands.
Certain lands were conveyed to the Cities through ANCSA 14(c)(3) actions. Plats 92-6
(Kobuk), 94-5 (Shungnak), recorded in the Kotzebue Recording District, show these lands.
ANCSA 14(c)(3) land transfers have not occurred in Ambler.
Section 3
Cosmos Hills Area Background Information
Feasibility Study and Conceptual Design Report Page 21
Cosmos Hills Hydro Feasibility
NANA owns much of the land surrounding the villages. Native allotments are also located
throughout the area. The State of Alaska owns the Dahl Creek Airport.
Various plats and surveys provide for some rights-of-way (ROW) in the area; however, most
of the existing roads and trails in the Cosmos Hills area do not have ROW.
3.8 Topography and Soils
The topography of the Cosmos Hills is moderately rugged and mature, with approximately
3,000 feet of relief. The southern drainages of the Cosmos Hills, including Cosmos Creek,
Wesley Creek, and Dahl Creek, typically flow to the southwest, away from the range.
The upper portion of the Cosmos Hills contains rock from a schist belt, but also dolostone,
metalimestone, and marble. The lower hills on the south side of the Cosmos Hills are
characterized by a sedimentary series of conglomerate, sandstone, and shale.
Glacial deposits are present between elevation 400 and 800 feet along portions of the
southern flanks of the Cosmos Hills. The glacial drift has been mapped in areas between the
flood plains of the Cosmos, Wesley, and Dahl Creeks. Erratic boulders are present up to
elevation 2,200 feet. Subdued moraine deposits are found in the Shungnak and Kogoluktuk
River valleys.
Surficial geologic mapping of the Cosmos Hills shows bedrock covered with shallow
surficial deposit characteristics along most of the highland above about 600 to 800 feet
elevation. Aeolian and alluvial deposits, primarily sand are located between the floodplains
of Cosmos, Wesley, and Dahl Creeks between elevations of about 400 and 600 feet. Glacial
drift deposits exist between elevations of about 200 and 400 feet. Alluvial floodplain
deposits of the Kobuk River lie to the south of the Cosmos Hills, along with terrace and fan
deposits abutting the higher drift deposits.
The Kobuk River region, in the vicinity of the Cosmos Hills, is mapped as having
discontinuous permafrost. Discontinuous permafrost is identified as 50 to 90 percent
potential coverage, so it can be expected that some permafrost will be present within the
project areas.
3.9 Gravel Sources
There are no commercial gravel pits in the area. However, two previously developed
material sites exist near the Dahl Creek airport. The material sites are located within alluvial
fans of the Cosmos Hills, downstream of the Dahl Creek site. The existing cut slopes at the
material sites show alluvial deposits of sand and gravel with cobbles and random boulders.
Maintenance pits along the Bornite Mine Road reveal material that varies in quality, ranging
from dune sand to sandy gravel to bedrock.
It is likely that additional material sites can be located within the project area, if the existing
pits do not contain enough material for a proposed project.
Section 3
Cosmos Hills Area Background Information
Feasibility Study and Conceptual Design Report Page 22
Cosmos Hills Hydro Feasibility
3.10 Climate
The Cosmos Hills lie within Alaska’s Continental Climatic Zone. The Continental Climatic
Zone is characterized by having long, cold winters and warm summers. Generally, the
Continental Climatic Zone has great temperature variations, low cloudiness, low
precipitation, and low humidity.
The climatic data summarized in the table below was obtained from the Environmental Atlas
of Alaska and from the Western Regional Climate Center (WRCC).
Table 3-3: Cosmos Hills Area Climate Data
Mean Annual Temperature ............................................................................ 22.5 °F
January Mean Temperature............................................................................. -10 °F
July Mean Temperature .................................................................................... 60 °F
Extreme Low Temperature ............................................................................. -74 °F
Extreme High Temperature............................................................................... 93 °F
Mean Annual Precipitation ..................................................................... 17.5 inches
Mean Annual Snowfall .............................................................................. 65 inches
Thawing Index ................................................................................. 2,000 °F – days
Design Thawing Index ..................................................................... 2,600 °F – days
Freezing Index ................................................................................. 6,200 °F – days
Design Freezing Index ..................................................................... 7,400 °F – days
Heating Degree Days (65 °F base) ................................................ 15,178 °F – days
Prevailing Winds ................................................................................ East-Southeast
3.11 Natural Hazards
According to the U.S. Army Corps of Engineers’ (USACE) Flood Plain Management
Services, flooding occurs in Kobuk most years. The floods are usually caused by ice jams
on the Kobuk River.
The project areas are well above the normal flood levels of the Kobuk River, but local
flooding within the creeks and rivers within the project area can be expected.
The Kobuk Fault System zone extends along the southern border of the Brooks Range for
approximately 300 miles, and is approximately 20 miles wide. In general, the fault system
has been relatively inactive in the recent historical period. A rare series of shallow
earthquakes was recorded about 40 miles to the east in October 1980, with magnitudes
ranging between 4.0 and 5.0. A magnitude 7.3 earthquake was recorded in 1958, with an
epicenter near Huslia, approximately 85 miles to the south.
Section 4
Cosmos Hills Hydrology
Feasibility Study and Conceptual Design Report Page 23
Cosmos Hills Hydro Feasibility
4. COSMOS HILLS HYDROLOGY
4.1 Hydrology Overview
The USGS has maintained two stream discharge stations in proximity to the project area.
One is located on Dahl Creek and the other on the Kobuk River. Additional stream
discharge measurements and data collection have also been done on Cosmos Creek, Wesley
Creek, Dahl Creek, and the Kogoluktuk River by Geo-Watersheds Scientific (GWS) as part
of this project.
The stream hydrology in the Cosmos Hills region is strongly related to the temperature
regime in the winter. During the summer, the stream hydrology is mostly related to the
snow accumulation during the previous winter and precipitation.
4.2 USGS Stream Discharge Data
The USGS has maintained and collected stream flow data on Dahl Creek from 1986 to the
present day and on the Kobuk River from 1976 to the present day. An investigation of the
flow measurements and the derivation and application of rating curves by the USGS was not
performed as part of this project. The tables and charts below summarize the data from
these two stations.
Section 4
Cosmos Hills Hydrology
Feasibility Study and Conceptual Design Report Page 24
Cosmos Hills Hydro Feasibility
Table 4-1: Monthly Flows – Dahl Creek
(USGS 15743850 DAHL C NR KOBUK AK, 11 sq mi Drainage Area *)
Month
Average
Monthly Flow
(cfs)
Median
Monthly Flow
(cfs)
5% Recurrence
Minimum Daily Flow
(cfs)
Daily
Maximum Flow
(cfs)
1 4.3 4.4 2.0 7.6
2 3.7 3.5 1.7 6.4
3 3.4 3.0 1.4 5.8
4 5.3 3.4 1.5 400.0
5 58.9 39.5 3.4 678.0
6 55.4 45.0 12.0 250.0
7 33.5 29.0 8.8 140.0
8 60.1 40.0 12.0 1,400.0
9 46.1 35.0 13.0 318.0
10 27.3 23.0 9.0 103.0
11 10.3 9.2 4.0 28.0
12 6.2 5.7 3.0 14.0
Average 26.2 20.1
* Dahl Creek monthly flows from 7,495 daily records, 7/17/1986 to 7/24/2013 (9,869 days)
cfs = cubic feet per second
Exhibit 4-1: Daily Flow Chart for USGS 15743850 DAHL C NR KOBUK AK
0
10
20
30
40
50
60
70
80
90
100
1/1 1/31 3/2 4/1 5/1 5/31 6/30 7/30 8/29 9/28 10/28 11/27 12/27Discharge, cfsDay of Year
Daily Flow, cfs Average Daily Flow, cfs
Median Daily Flow, cfs 5% Recurrence Minimum Daily Flow, cfs
Section 4
Cosmos Hills Hydrology
Feasibility Study and Conceptual Design Report Page 25
Cosmos Hills Hydro Feasibility
Table 4-2: Monthly Flows – Kobuk River
(USGS 15744500 KOBUK R NR KIANA AK, 9520 sq mi Drainage Area *)
Month
Average
Monthly Flow
(cfs)
Median
Monthly Flow
(cfs)
5% Recurrence
Minimum Daily Flow
(cfs)
Daily
Maximum Flow
(cfs)
1 2,507 2,500 1,500 4,900
2 2,047 1,900 1,200 3,200
3 1,806 1,800 1,100 2,700
4 1,766 1,700 1,000 7,300
5 27,765 7,000 1,300 160,000
6 44,715 37,950 14,195 155,000
7 20,800 17,200 9,092 71,900
8 29,780 23,600 7,896 129,000
9 27,585 20,900 8,629 138,000
10 13,145 11,000 4,400 48,700
11 5,391 5,000 2,700 16,000
12 3,404 3,400 2,100 7,600
Average 15,059 11,163
* Kobuk River monthly flows from 11,718 daily records, 9/1/1976 to 9/30/2012 (13,178 days)
Exhibit 4-2: Daily Flow Chart for USGS 157444500 KOBUK R NR KIANA AK
0
10000
20000
30000
40000
50000
60000
1/1 1/31 3/2 4/1 5/1 5/31 6/30 7/30 8/29 9/28 10/28 11/27 12/27Discharge, cfsDay of Year
Daily Flow, cfs Average Daily Flow, cfs
Median Daily Flow, cfs 5% Recurrence Minimum Daily Flow, cfs
Section 4
Cosmos Hills Hydrology
Feasibility Study and Conceptual Design Report Page 26
Cosmos Hills Hydro Feasibility
An analysis of long term trends shows no significant changes occurring in the Kobuk River.
The pattern for Dahl is similar except that the magnitude of annual variations is higher and
there is a slight downward trend for the average and a slight upward trend for the median.
Exhibit 4-3: Kobuk River Annual Discharge Trend
4.3 GWS Stream Discharge Data
Data collected, processed, and analyzed by GWS (shown as LILLY in exhibits) covers a
period of time from August 2010 through September 2011. Their report, entitled “Cosmos
Hills Hydrologic Network Installation and Operation, August 2010 – December 2011,” was
issued in May 2012 and includes elevation surveys, flow measurements, rating curve
development, and links to raw and processed data. This report has been previously
submitted, but a summary is included in Section 2.3.8.
The effort by GWS did not include an opportunity to gather significant numbers of low flow
measurements for rating curve development. Rating curves were extrapolated using
elevation surveys, stream character and qualitative judgment, and best fit extrapolation of
higher flow measurements.
The resulting data from the GWS hydrologic investigation is approximately a complete year
of daily average discharge data, based on hourly intervals, for Cosmos Creek, Wesley Creek,
Dahl Creek, and the Kogoluktuk River. The measurements were taken at locations near the
intake sites of the proposed projects without correcting for the minor differences in drainage
area due to the slightly different locations. Other than the charts shown, data from the report
0
5000
10000
15000
20000
25000
30000
1 6 11 16 21 26 31Kobuk River Annual Average Discharge, cfsConsecutive Year with >365 days of data (Year 1 = 1976)
Kobuk River Average Annual Flow Kobuk River Median Annual Flow
Section 4
Cosmos Hills Hydrology
Feasibility Study and Conceptual Design Report Page 27
Cosmos Hills Hydro Feasibility
is not reproduced here. The data (raw and processed) used to prepare the charts in this
report is being submitted in electronic format on a USB drive.
Additional data is currently being collected by the project proponent at the Wesley Creek
and Kogoluktuk River sites. This raw, unprocessed data is being stored until the project
advances and additional funds become available to process and analyze it. All available
data, both raw and processed is available at the following website:
Website: http://cosmos.gwscientific.com/Main/HomePage
Password: “hydropower”
4.4 Data Analysis
Review of the hydrology data and comparison of the two sources indicates the following:
• The 2010 water year was generally low. The USGS data shows that the 2010 water
year was the 3rd lowest for Dahl Creek (out of the 16 years with 365 days of record),
while the Kobuk River ranked 11th out of 32 years. The annual average flow in
Dahl Creek in 2010 was 18.8 cfs versus 24.5 cfs for the 16-year average. The Kobuk
River 2010 average annual flow was 12,900 cfs versus 15,100 cfs for the 32-year
average.
• Low flow data at the USGS Dahl Creek site shows a quicker drop in early winter
than the GWS data.
• Direct comparison of the USGS and GWS data on Dahl Creek, after scaling for
relative basin areas, shows the USGS data is consistently lower (see Exhibit 4-4,
below).
• The GWS Cosmos Creek data closely matches the USGS Dahl Creek data through
most of the year.
• The GWS Kogoluktuk River data closely matches the USGS Kobuk River data from
June through September.
• The Kogoluktuk River and Kobuk River exhibit less total annual discharge than the
small, mountainous basins. This is probably due to the smaller basins being entirely
mountainous with more annual precipitation.
The comparisons made with all the data sets from USGS and GWS in 2010 were done using
discharge measurements scaled down to a unit value. Each discharge record is divided by
the drainage area to produce flows in units of cfs per square mile. The resulting comparison
is shown in Exhibit 4-5, below.
Section 4
Cosmos Hills Hydrology
Feasibility Study and Conceptual Design Report Page 28
Cosmos Hills Hydro Feasibility
Exhibit 4-4: Chart Comparing the USGS and G-W Scientific (Lilly) Dahl Creek Discharge Data
Exhibit 4-5: Chart of Cosmos Hills Region Unit Discharge Data, 2010 Water Year
0
5
10
15
20
25
30
35
40
45
50
Oct-10Oct-10Nov-10Dec-10Jan-11Feb-11Mar-11Apr-11May-11Jun-11Jul-11Aug-11Sep-11Dahl Creek Discharge at Proposed Hydro Intake, cfsDay of Year
LILLY Dahl
USGS Dahl scaled to LILLY Dahl
0
1
10
Oct-10Nov-10Dec-10Jan-11Feb-11Mar-11Apr-11May-11Jun-11Jul-11Aug-11Sep-11Unit Discharge, log scale, cfs per sq miDay of Year
USGS Dahl, 2010
USGS Kobuk, 2010
LILLY Cosmos
LILLY Wesley
LILLY Dahl
LILLY Kogoluktuk
Section 4
Cosmos Hills Hydrology
Feasibility Study and Conceptual Design Report Page 29
Cosmos Hills Hydro Feasibility
4.5 Recommended Stream Discharge Data for Developmental Analysis
Given the impracticality of investing many years of effort into flow measurements and
rating curve development for small, remote projects, it is standard practice in Alaska to
apply discharge data from a USGS station with a long history to the basin proposed for
hydroelectric development. This is required so that long-term trends can be identified and
an unusual water year is not relied upon for the long-term economic evaluation. This
approach requires some verification that there exists a quantifiable correlation between the
basin of interest and the basin with a long discharge history. Such a correlation becomes
particularly important when evaluating projects with marginal economics due to water
availability or projects with potential fishery impacts.
The concentrated effort conducted by GWS covering all the basins of interest for
hydroelectric development was performed and subsequently established the necessary
correlations and verifications to apply the long term USGS data for analysis. It is noted that
GWS states that the USGS estimated winter flows and the winter measurements on the
Kogoluktuk are more accurate.
The modeling for this study will rely on USGS Dahl Creek median daily flow data for the
hydro sites at Wesley Creek and Dahl Creek and USGS Kobuk River median daily flow data
for the hydro site at the Kogoluktuk River. Application will be based on scaling of basin
areas. In comparing the winter flows on the Kogoluktuk by GWS with those of the USGS
on the Kobuk the differences appear minor, with the adoption of the USGS Kobuk regime
being more conservative. Adjustment of the scaled USGS Kobuk River winter data does not
appear warranted at this time.
Table 4-3 shows the resulting monthly discharge data for the modeling of flows at the
project intake sites.
Section 4
Cosmos Hills Hydrology
Feasibility Study and Conceptual Design Report Page 30
Cosmos Hills Hydro Feasibility
Table 4-3: Monthly Average of Median Daily Flows used for Modeling
Basin Area 5.24 Sq. Mi. 8.50 Sq. Mi. 424 Sq. Mi.
Month
Wesley
Monthly Flow
(cfs)
Dahl
Monthly Flow
(cfs)
Kogoluktuk
Monthly Flow
(cfs)
1 2.0 3.3 111
2 1.6 2.6 85
3 1.5 2.4 78
4 1.6 2.6 76
5 20.2 32.8 938
6 21.6 35.1 1727
7 13.1 21.3 778
8 20.2 32.8 1057
9 17.5 28.3 914
10 10.5 17.1 522
11 4.4 7.2 235
12 2.8 4.5 156
Average 9.8 15.9 558
4.6 GWS Air and Water Temperature Data
Air temperature and water data collected by GWS covers a period of August 2010 through
February 2014, for Wesley Creek and Kogoluktuk River, and August 2010 through
September 2011 for Dahl Creek. The following charts summarize this data.
Section 4
Cosmos Hills Hydrology
Feasibility Study and Conceptual Design Report Page 31
Cosmos Hills Hydro Feasibility
Exhibit 4-6: Wesley Creek, Hourly Air Temperature Data
Exhibit 4-7: Wesley Creek, Hourly Water Temperature Data
-60
-40
-20
0
20
40
60
80
100
Jul-10Oct-10Jan-11Apr-11Jul-11Oct-11Jan-12Apr-12Jul-12Oct-12Jan-13Apr-13Jul-13Oct-13Jan-14Apr-14Temperature, Degrees FDate
30
32
34
36
38
40
42
44
Jul-10Oct-10Jan-11Apr-11Jul-11Oct-11Jan-12Apr-12Jul-12Oct-12Jan-13Apr-13Jul-13Oct-13Jan-14Apr-14Temperature, Degrees FDate
Section 4
Cosmos Hills Hydrology
Feasibility Study and Conceptual Design Report Page 32
Cosmos Hills Hydro Feasibility
Exhibit 4-8: Dahl Creek, Hourly Air Temperature Data
Exhibit 4-9: Dahl Creek, Hourly Water Temperature Data
-60
-40
-20
0
20
40
60
80
100
Jul-10Aug-10Sep-10Oct-10Nov-10Dec-10Jan-11Feb-11Mar-11Apr-11May-11Jun-11Jul-11Aug-11Sep-11Oct-11Nov-11Temperature, Degrees FDate
30
32
34
36
38
40
42
44
46
Jul-10Aug-10Sep-10Oct-10Nov-10Dec-10Jan-11Feb-11Mar-11Apr-11May-11Jun-11Jul-11Aug-11Sep-11Oct-11Nov-11Temperature, Degrees FDate
Section 4
Cosmos Hills Hydrology
Feasibility Study and Conceptual Design Report Page 33
Cosmos Hills Hydro Feasibility
Exhibit 4-10: Kogoluktuk River, Hourly Air Temperature Data
Exhibit 4-11: Kogoluktuk River, Hourly Water Temperature Data
-60
-40
-20
0
20
40
60
80
100
Jul-10Oct-10Jan-11Apr-11Jul-11Oct-11Jan-12Apr-12Jul-12Oct-12Jan-13Apr-13Jul-13Oct-13Jan-14Apr-14Temperature, Degrees FDate
30
34
38
42
46
50
54
58
62
66
70
Jul-10Oct-10Jan-11Apr-11Jul-11Oct-11Jan-12Apr-12Jul-12Oct-12Jan-13Apr-13Jul-13Oct-13Jan-14Apr-14Temperature, Degrees FDate
Section 4
Cosmos Hills Hydrology
Feasibility Study and Conceptual Design Report Page 34
Cosmos Hills Hydro Feasibility
Section 5
Existing Diesel Generation and Transmission System
Feasibility Study and Conceptual Design Report Page 35
Cosmos Hills Hydro Feasibility
5. EXISTING DIESEL GENERATION AND TRANSMISSION SYSTEM
5.1 Basic Configuration
5.1.1 Kobuk
The electric energy in Kobuk is produced at the diesel generation plant in Shungnak and
delivered through the existing Shungnak-Kobuk intertie. The intertie is approximately 7
miles in length and has been in existence for about 30 years (AVEC Kobuk).
Occasionally, the intertie experiences outages. In 2010 data provided by AVEC, an outage
that occurred from 5:30 pm on December 19, 2010 until 7:45 pm on December 25, 2010 was
evident by an average reduction in Shungnak generation of 72.5 kW, based on the projected
load had the outage not occurred. The economic modeling in this study, which uses this
2010 data as a basis, utilized the projected load so that the impact of the outage did not have
an annually recurring impact. The economic model used does not include intertie outages.
During an outage, Kobuk must self-generate electricity with their existing diesel plant. This
plant is reported to have a capacity of 75 kW (NWAB Kobuk Comp Plan).
AEA’s Power Cost Equalization Program (PCE) report for FY 2012 indicates that Kobuk
purchased 529 MWh of energy and sold 504 MWh of energy. This data indicates that the
average demand in Kobuk is 57.5 kW and that the intertie has an average line loss of 4.6%.
The Alaska Department of Commerce, Community, and Economic Development recently
allocated approximately $1.5M to the Northwest Arctic Borough for improvements to the
Shungnak-Kobuk intertie. It is assumed for this study that the existing intertie will have the
capacity to supply the entire electric energy needs of Shungnak and Ambler when supplied
by any of the hydro projects located near Kobuk.
5.1.2 Shungnak
Based on review of filings with the Regulatory Commission of Alaska (RCA), the diesel
electric generation plant in Shungnak, that also provides power to Kobuk, consists of the
units shown in Table 5-1.
Table 5-1: Shungnak Power Generation Units
Engine Size (kW)
John Deere 6619 202
CAT 3406 297
Detroit Diesel S60 314
Cummins KTA1150 397
The diesel generation efficiency for Shungnak in 2012 was 13.63 kWh/gal. For modeling, a
fixed efficiency is used for all loads, along with a minimum loading of 40.4 kW.
Additionally, a diesel is expected to run if the peak demand is within 15 kW of the hydro
output.
Section 5
Existing Diesel Generation and Transmission System
Feasibility Study and Conceptual Design Report Page 36
Cosmos Hills Hydro Feasibility
5.1.3 Ambler
Based on review of filings with the RCA, the diesel electric generation plant in Ambler
consists of the units shown in Table 5-2.
Table 5-2: Ambler Power Generation Units
Engine Size (kW)
Cummins KTA1150 271
Detroit Diesel S60 314
Cummins KTA1150 397
The diesel generation efficiency for Ambler in 2012 was 13.99 kWh/gal. For modeling, a
fixed efficiency is used for all loads, along with a 40.4 kW minimum loading. Additionally,
a diesel is expected to run if the peak demand is within 15 kW of the hydro output.
5.1.4 Proposed Ambler Intertie
Two of the proposed project alternatives, the Kogoluktuk and the combined Wesley and
Dahl, have enough capacity to meet a substantial portion of the electrical demand in Ambler
in addition to the demand in Kobuk and Shungnak. In order to meet this potential market, a
proposed intertie connecting Shungnak-Kobuk with Ambler is included in the modeling of
the future electric system. Table 5-3 summarizes the intertie parameters.
Table 5-3: Proposed Ambler Intertie
Length 25.3 miles
Unit Cost $450,000 per mile
Construction Cost $11,385,000
O&M Cost $22,770 per year
Design/Permitting Funding Start 7/1/2015
Online Date 7/1/2018
The hydroelectric modeling and analysis, which included a base case consisting of diesel-
only electric generation, showed that the total net present cost of diesel-only generation was
reduced by about $12 million when the intertie is constructed. (See Table 7-9: Net Present
Cost of Electric Generation, Millions of 2013 $.) This is due to reduced delivery cost for
fuel in Ambler, the reduced O&M cost from having one diesel generation plant instead of
two, and the associated avoided capital cost for a diesel electric plant and tank farm. With
heat value included, the savings are reduced by an average of $4.4 million due to waste heat
recovery being available from a single plant instead of two. (See Table 7-111: Net Present
Value of Using “Excess” Electricity for Heat, Millions of 2013 $.)
AVEC estimates the non-fuel production related savings from an intertie (taking a diesel
power plant offline) is $167,000 per year. Non-fuel production related savings include the
costs of oil, overhauls, and similar maintenance incurred when the plant is operational.
Section 5
Existing Diesel Generation and Transmission System
Feasibility Study and Conceptual Design Report Page 37
Cosmos Hills Hydro Feasibility
Further adding to the intertie benefit, for just the base case of diesel-only, is the reduced
capital expenditure that is avoided by not having to replace/reconstruct the diesel generation
plant in Shungnak. The capital expense of construction of a replacement diesel power plant
and fuel storage facility in Shungnak is approximately $18 million (AVEC Project Manager
communication). This cost appears significantly higher than expected. A more conservative
cost of $12 million each for Ambler and Shungnak is used for this study. The existing
facilities in Shungnak would serve for the purpose of emergency backup in the event the
intertie goes down (similar to the Kobuk power plant).
The conclusion is that the intertie will, or should be, constructed whether or not the
hydroelectric project is constructed because it will result in a net present savings of
approximately $12 million. The intertie provides net benefits to the diesel-only option, but
also allows the hydro options to offset generation in Ambler which is a significant net
benefit.
5.2 Existing Energy Generation
The combined annual generation for Shungnak-Kobuk and Ambler for the past five years is
shown in Table 5-4 (AIDEA PCE).
Table 5-4: PCE Electric Demand
Shungnak PCE Ambler PCE Combined PCE
FY Year
Energy
Generated,
kWh
Avg
Power,
kW
Energy
Generated,
kWh
Avg
Power,
kW
Energy
Generated,
kWh
Avg.
Power,
kW
2008 1,483,862 169 1,321,573 151 2,805,435 320
2009 1,477,747 169 1,245,599 142 2,723,346 311
2010 1,578,459 180 1,249,161 143 2,827,620 323
2011 1,546,541 177 1,314,441 150 2,860,982 327
2012 1,588,139 181 1,343,144 153 2,931,283 335
Escalation Rate 1.8% 0.9% 1.4%
The electrical demand in both communities has risen over the past several years. The
economic modeling assumes this trend will continue at a slightly conservative rate of 1% for
both communities. The projected generation for the next 50 years is shown in Table 5-5 and
Exhibit 5-1.
Table 5-5: Projected Energy Demand
Shungnak-Kobuk,
kWh
Ambler,
kWh
Combined,
kWh
FY 2013 (year 0) 1,606,819 1,329,832 2,936,651
FY 2038 (year 25) 2,060,636 1,705,419 3,766,056
FY 2063 (year 50) 2,642,626 2,187,084 4,829,710
Section 5
Existing Diesel Generation and Transmission System
Feasibility Study and Conceptual Design Report Page 38
Cosmos Hills Hydro Feasibility
Exhibit 5-1: Projected Electric Generation for Ambler and Shungnak
AVEC collects 15-minute interval energy demand (kWh) data from their power plants. This
data was reduced to a daily average power demand with a peak for each day for modeling
purposes. From this daily data a contiguous year, beginning on September 1, 2010, was
selected for subsequent modeling. The selected date range coincides with the water year
data collected by GWS. The selected daily data for economic modeling is shown in Exhibit
5-2.
Exhibit 5-2: Daily Power Demand
1,000,000
1,100,000
1,200,000
1,300,000
1,400,000
1,500,000
1,600,000
1,700,000
1,800,000
1,900,000
2,000,000
2008 2013 2018 2023 2028 2033Annual PCE Reported Diesel Electric Generation (kWh)Fiscal Year
Shungnak PCE Generated Energy
Ambler PCE Generated Energy
Shungnak Projected Load
Ambler Projected Load
100
150
200
250
300
350
400
450
500
550
600
9/1 10/1 11/1 12/1 1/1 1/31 3/3 4/2 5/3 6/2 7/3 8/2Power Demand (kW)Day of Year
Shungnak Average
Ambler Average
Combined Average
Combined Peak
Section 5
Existing Diesel Generation and Transmission System
Feasibility Study and Conceptual Design Report Page 39
Cosmos Hills Hydro Feasibility
5.3 Existing Energy Market
5.3.1 Fuel Costs
AVEC provided fuel purchase data for both Ambler and Shungnak-Kobuk. This data
includes the delivered location, delivery type, date, quantity (gal), and unit cost ($/gal) of
diesel fuel for electric generation from 2004 through 2012 and is summarized in the
following tables.
Table 5-6: AVEC Diesel Fuel Deliveries to Ambler, 2004 to 2012
Delivered Volume Unit Rate
Year Air
(gal)
Barge
(gal)
%
by Air
Air
($/gal)
Barge
($/gal)
Differential
($/gal)
2004 0 13,000 0% 2.43
2005 0 86,234 0% 2.57
2006 11,880 45,000 21% 4.62 2.50 2.13
2007 112,180 0 100% 5.67
2008 33,886 38,750 47% 6.74 5.12 1.62
2009 36,001 74,000 33% 5.08 3.16 1.92
2010 16,501 84,540 16% 5.88 3.77 2.11
2011 0 98,714 0% 5.04
2012 0 108,264 0% 4.16
Summary 210,448 548,502 24% 5.60 3.59 1.94
Table 5-7: AVEC Diesel Fuel Deliveries to Shungnak, 2004 to 2012
Delivered Volume Unit Rate
Year Air
(gal)
Barge
(gal)
%
by Air
Air
($/gal)
Barge
($/gal)
Differential
($/gal)
2004 0 110,510 0% 2.43
2005 0 48,550 0% 2.57
2006 96,980 69,779 58% 4.39 2.50 1.89
2007 57,983 0 100% 5.39
2008 86,076 0 100% 5.73
2009 72,000 50,628 59% 5.19 3.16 2.03
2010 74,900 50,422 60% 5.72 3.79 1.94
2011 105,469 0 100% 6.53
2012 58,196 90,968 39% 7.56 4.35 3.22
Summary 61,289 46,762 57% 5.79 3.13 2.27
Analysis of the 2004 to 2012 Ambler barged fuel price indicates that the fuel cost growth
rate is the same as the Los Angeles Ultra-Low Sulfur #2 Diesel which was 8.4% without
adjusting for inflation. The growth rate for the average of spot prices for Brent and West
Texas crude, the current benchmark for ISER fuel price projections, was 10.3% over the
Section 5
Existing Diesel Generation and Transmission System
Feasibility Study and Conceptual Design Report Page 40
Cosmos Hills Hydro Feasibility
same period without adjusting for inflation. This is well above the inflation for all items
(US West and Anchorage), which has been about 2.5%, resulting in a growth rate relative to
inflation of about 6%. This high rate of growth is not expected to continue.
Air vs. barge delivery and Fuel Price Projections. The economic analysis in this study uses
the data above and values from the University of Alaska, Institute of Social and Economic
Research (ISER) fuel price projection for 2013 (ISER 2013). Unfortunately, that report has
some problems as applied to Ambler and Shungnak. ISER’s fuel price projections use
statistical regression techniques on data from 1986 to 2012. ISER completed individual
regressions for over 150 rural communities. The result is a simple projection of past trends
into the future for each village without taking into account local knowledge or changes in
the fuel transportation circumstances. From ISER’s report: The projection of fuel prices
“provides an estimate of future values based on a statistical assessment of past relationships
under specific assumptions, but they are not a prediction that the specific assumptions will
happen.” (ISER 2013, p.3) Therefore, ISER’s statistical project implicitly assumes the
historical proportion of barge/air deliveries will remain true into the future.4 AVEC, NANA,
recent history, and local contacts indicate that this implicit assumption is untrue at present
and unlikely to be true for the future.
For most of the historic period on which ISER’s statistical project is based, barge delivery
has been the dominant method of fuel delivery. Over the last decade or so, AVEC has
experienced fluctuating but increasing instances when the river has been too low to receive
barges, and fuel has been delivered by air at a significant additional cost. Recent history is
displayed in Table 5-6. In 2011, the river was low enough that the barge was only able to
get in using a side-channel and then was hauled side-ways to the unloading location at
Ambler. The landing was unpleasant, touch-and-go, and somewhat dangerous. The barge
company is unlikely to attempt the trip in similar circumstances again. Shungnak, further
upriver, received all of its fuel through air delivery that year. This year (2013) is not yet
complete, but locals have told us that the river is low enough for villagers to walk across –
an unusual situation. All fuel delivery this year has been by air at a cost of $7.55/gallon for
Ambler and $7.00/gallon for Shungnak.
There are various explanations given for the barge failures. We have heard that the river is
sedimenting up near the villages, that the high flows are decreasing, and that ice is staying
longer in Kotzebue Sound so that barges miss the higher flows in the river. None of these
explanations have been independently verified; all or none may be true. However, AVEC
and local groups are quite definite that the incidence of air delivery of fuel has increased and
is likely to remain high in the future. Therefore, the ISER fuel project underestimates the
true fuel price at the villages.
Fuel Price Scenarios. Despite the fact that ISER projections likely underestimate true fuel
prices for the projects, this analysis uses ISER’s projections as a basis for the economic
analysis. Because funding for the next phase of this project is expected to come from the
Renewable Energy Fund and is part of a larger pool of projects competing for the same
4 The conclusion concerning the future price project and this implicit assumption was confirmed in personal
and e-mail conversations with Ms. Fay, Ms. Meléndez, and Mr. Pathan, three of the ISER report’s four authors.
Section 5
Existing Diesel Generation and Transmission System
Feasibility Study and Conceptual Design Report Page 41
Cosmos Hills Hydro Feasibility
funding, it is appropriate to adopt the ISER projection so that equal comparisons can be
made. However, the analysis makes two changes.
First, the analysis omits the lowest of ISER’s fuel price scenarios, and only uses Medium
and High. ISER’s “Low” projection greatly underestimates likely prices at these villages.
(It may work for the other 150 villages in the projection). The Low projection for Ambler
assumes a price of $5.34 for 2013 (more than $2 less than actual prices), and then goes down
to below $5/gallon but never comes back to that price. The projection ends in 2035 at a
price of $4.34/gallon (real prices, without inflation). This projection is so far below
AVEC’s experience and expectations for fuel delivery that using this price forecast would
produce unsupportable conclusions. Given recent experience and the likelihood of at least
periodic if not permanent air delivery, it is not credible that fuel prices will average between
$4.18 and $4.34/gallon (the ISER Low projection) for most of the project’s life.
The problem of underestimating prices due, in part, to increased air delivery, also plagues
the medium and high price scenarios, though not to the same extent. Therefore, these two
ISER scenarios the Medium and High forecast are used for economic modeling. The
ISER projected inflation-adjusted growth rate for Ambler is 1.5% for the Medium projection
and 1.7% for the High projection.
The second change is it that the analysis includes a third price projection. The near term
fuel costs provided by ISER do not reflect current prices. They are far below what the
utility is experiencing. AVEC projects a third price fuel scenario based on a price of barge
delivered fuel of $5.50 per gallon. This third price scenario, termed AVEC 2013, also
assumes some air delivery. Specifically, it assumes that air deliveries are $2 more than
barge prices. It assumes that 50% of the fuel needs in Ambler are met by air deliveries and
that 100% of the fuel needs in Shungnak are met by air deliveries.
The AVEC 2013 fuel price for Ambler in FY 2013 is $5.50/gallon + $1.00/gallon air
surcharge = $6.50/gallon (still over $1 less than the actual price). By similar logic it
assumes a Shungnak fuel price of $7.50 per gallon. ($5.50 + $2.00 = $7.50/gallon, which is
the actual 2013 price being paid by AVEC). The AVEC 2013 scenario uses a rate of growth
equal to the ISER High projection. (The economic conclusions would not be greatly
different with the ISER Medium rate of growth was used).
Exhibit 5-3 compares historic and projected fuel prices. Table 5-8 shows the projections for
Ambler and Shungnak in 2013, 2038, and 2063.
Section 5
Existing Diesel Generation and Transmission System
Feasibility Study and Conceptual Design Report Page 42
Cosmos Hills Hydro Feasibility
Exhibit 5-3: Ambler Fuel Pricing Projections
Table 5-8: Fuel Price Projection Scenarios, Fuel Price in 2013 $/gal
FY 2013 (year 0) FY 2038 (year 25) FY 2063 (year 50)
Ambler Shungnak Ambler Shungnak Ambler Shungnak
ISER Medium 5.34 6.21 7.10 8.60 10.48 13.39
ISER High 5.34 6.21 9.60 12.01 14.64 19.08
AVEC 2013 6.50 7.50 9.88 11.40 15.02 17.34
5.3.2 Nonfuel Costs
Nonfuel expenditures, such as lube oil, engine overhauls, parts replacement, etc., are
categorized as production related. These are costs that are directly related to the number of
hours the diesel engine operates. Nonproduction costs, such as administration, buildings,
and transmission are relatively fixed, regardless of diesel engine run time or energy
generated. The nonfuel costs that can be avoided when a hydro or intertie completely avoids
running a diesel plant (diesels off) are the production related nonfuel costs.
AVEC reports that the nonfuel costs avoided when a diesel plant is idled are $167,000 per
year. This figure is confirmed based on the following review using the most recent PCE
annual report filed by AVEC with the RCA as shown in Table 5-9.
1
2
3
4
5
6
7
8
9
10
2004 2006 2008 2010 2012 2014 2016 2018 2020 2022 2024 2026 2028 2030 2032 2034 2036 2038Price per gallon (2013 US $)Year
Fuel Pricing, Inflation Adjusted (US West Coast CPI, all items), 2013 $
Ambler Barge Delivered Fuel Price
Average of Brent and WTI Oil Prices per gal
Los Angeles Ultra-Low Sulfur #2 Diesel Price
ISER 2013 Ambler Medium Fuel Projection
ISER 2013 Ambler High Fuel Projection
AVEC 2013 Ambler Fuel Projection
Section 5
Existing Diesel Generation and Transmission System
Feasibility Study and Conceptual Design Report Page 43
Cosmos Hills Hydro Feasibility
Table 5-9: Nonfuel Costs from AVEC 2012 PCE Annual Report
Account Description 2012 Cost
547.1 Fuel Inventorying $34,872
547.2 Fuel Purchasing $32,169
547.3 Fuel Pipeline & Header $25,138
547.5 Fuel Spill Cleanup & Remediation $175,411
548 Power Generation Expenses $27,170
548.1 Generation Exp- Lube Oil $236,337
549 Misc. Generation Expenses $657,463
553 Maintenance of Gen & Electric Equip $611,581
553.2 Technical In-house Service - Generation $7,706
553.3 Generation Plant - Scheduled Maintenance $1,412,904
553.5 Generation Plant Overhauls $538,866
553.9 Power Plant Operator Daily CK $1,761,495
553.999 O/H For Power Production $1,883,237
554 Maintenance Other Power Production $545,057
AVEC 2012 Total Production related nonfuel costs $7,949,406
AVEC 2012 Energy Generated, kWh 78,802,401
Production related nonfuel avoided rate, $/kWh' $0.101
AVEC 2012 PCE reported number of power plants 48
Production related nonfuel cost avoided when diesels are off
Cost avoided per plant per year $165,613
Costs avoided per plant run hour $18.91
Economic modeling uses AVEC's nonfuel production related savings from an intertie
(taking a diesel power plant offline) of $167,000 per year which equates to approximately
$19 per plant run hour. Production related nonfuel costs are assumed to change at 50% of
the rate of fuel change.
Section 5
Existing Diesel Generation and Transmission System
Feasibility Study and Conceptual Design Report Page 44
Cosmos Hills Hydro Feasibility
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Section 6
Alternative Project Descriptions
Feasibility Study and Conceptual Design Report Page 45
Cosmos Hills Hydro Feasibility
6. ALTERNATIVE PROJECT DESCRIPTIONS
6.1 Wesley Creek
6.1.1 Characteristics of Wesley Creek
The Wesley Creek project would be a run-of-river project with a small diversion dam and
intake, a long buried penstock pipeline, a small Pelton turbine and powerhouse, and a
tailrace back to the creek. The project would also include an access road, a transformer, and
a high-voltage transmission line.
At this location, the upstream basin catchment area is approximately 5.2 square miles. It is
noted that it would be feasible to divert two additional drainage basins from the northern
watershed boundary into the Wesley Creek basin adding 1.9 and 1.2 square miles,
respectively.
The only fish observed in Wesley Creek were Dolly Varden and Slimy Sculpin. The
locations and numbers of specimens collected during the Aquatic Resources study are
shown in Figure 2, located at the end of this section. Maintaining fish habitat is addressed in
Section 8 - Project Development Issues.
The conceptual design plans for the Wesley Creek Hydro Project are included in Appendix
A. The general arrangement of the project features is described below.
6.1.2 Intake
The intake location, at an elevation of approximately 660 feet, is situated just downstream
from a small tributary entering Wesley Creek and approximately 1,200 feet upstream of the
Upper Wesley Creek Bridge. At this location, the stream begins a descent from the
relatively wide, flat valley interspersed with wetlands, into the narrower and steeper valley
that gradually flattens as it empties onto the Kobuk River valley.
The intake site is littered with boulders and cobbles and is confined by the Bornite Road to
the west and mountainous topography to the east. The stream channel can be expected to
meander between these two boundaries. Currently, it flows down the middle of the valley,
has banks that are approximately two to three feet high and 35 feet across, and has a gradient
of approximately five percent.
Removal of debris such as vegetation, sand, and gravel will be required at the intake to
reduce wear and clogging of the turbine. The layout of the intake will facilitate this removal
along with a debris boom and the hydraulics of the intake (i.e. maintaining velocity past the
screens so that a small percentage of the total flow is taken). The intake system should also
take into account clogging potential due to frazil ice. This can be done with non-metallic
materials or other means of dislodging frazil ice from the intake screens. It may also make
sense to remove the screens entirely when the frazil ice is likely to form in the early winter,
and possibly in the spring, when there is no ice and snow cover to reduce the heat loss from
the flowing water. Additional considerations include the significant buildup of ice cover
over the winter and potential glaciation events. It is recommended that a pool be established
Section 6
Alternative Project Descriptions
Feasibility Study and Conceptual Design Report Page 46
Cosmos Hills Hydro Feasibility
with a minimum water depth of seven feet to accommodate ice build-up so that flow can be
maintained into the intake during the winter. Winter ice depth investigations should be done
to confirm the proposed intake concept.
The intake structure at Wesley Creek would consist of a 7-foot-high concrete diversion wall
angled to direct the flow of water past the structure. The intent is to increase the velocity
while also deepening the pool of water to enhance the quality of water being diverted. The
intake will consist of a concrete box structure with flat plate fine screens situated parallel to
the water flow. The screens will be located a minimum of 1 foot above the stream bed. The
intake capacity would be 15 cfs and water would be diverted at all times. To maintain flow
through the intake structure, the hydroelectric plant would bypass water during low flow
periods, even though there will be no power output when flows drop below the minimum
required for the turbines to operate (approximately 1 to 2 cfs). Any prescribed
environmental flows would effectively eliminate the potential for winter power production.
At flows higher than 15 cfs, the intake would be completely submersed. The intake
structure would have approximately one foot of freeboard above the screens during the
average summer flows.
Additional design considerations that must be addressed during the next phase of design
include a hydraulic model of the stream flows and a sediment transport study. An existing
conditions hydraulic model will be based on the current topography of the stream bed to
further define the flow patterns in Wesley Creek.
Data from the sediment transport study will be utilized to design the scour protection and
control for the intake structure and diversion dam. A cutoff wall driven to the bedrock and
connected to the diversion dam is anticipated with bank protection along both sides of
Wesley Creek. Seepage control measures will be considered if deemed necessary to prevent
erosion around the structure.
6.1.3 Penstock
The penstock for the Wesley Creek powerhouse will follow the Bornite Road alignment for
approximately two-thirds of the way to the powerhouse. From the intake, it will be routed
along the east side of the road down to the bridge, cross the creek suspended from the
bridge, continue approximately 3,300 feet along the east side of the road, cross the road at a
low point in the road, and then continue downhill to the powerhouse cutting diagonally
across the contours.
The conceptual design for the penstock pipeline is a 24-inch diameter bare high-density
polyethylene (HDPE) pipe buried in an insulated trench. At the bridge and road crossings,
the pipe will be insulated and jacketed arctic pipe. The overall length of the penstock will
be approximately 7,750 linear feet.
Section 6
Alternative Project Descriptions
Feasibility Study and Conceptual Design Report Page 47
Cosmos Hills Hydro Feasibility
Photo 6-1: Wesley Creek Road and Gaging Station at Bridge
HDPE was selected over other pipe materials for several reasons. HDPE has the capability
to adequately handle the almost 300 feet of static head, performs well in cold climates, can
tolerate a less than perfect bedding, and the fusible connections will minimize leaks at joints.
The pipeline size selected for various hydraulic capacities is shown in the Table 6-1, with
selection based on limiting head loss to 15% of the static head.
Table 6-1: Wesley Creek - Penstock Diameters and Hydraulic Capacity
Pipe Diameter
(inch)
Max. Flow
(cfs)
18 8
20 9
22 11
24 15
26 19
28 23
30 28
6.1.4 Powerhouse
The gradual run out of Wesley Creek from the Cosmos Hills onto the Kobuk River valley
complicates the identification of a powerhouse site. The decline in the rate of elevation drop
requires balancing the cost of additional energy output throughout the year with the cost of
extra pipeline and access road. The powerhouse site selection is further complicated when
coupled with the Dahl Creek project. A combined project allows the opportunity to slightly
undersize the pipeline, which sacrifices summer peak output, but improves project
economics. The recommended elevation of approximately 370 feet for the powerhouse is
Section 6
Alternative Project Descriptions
Feasibility Study and Conceptual Design Report Page 48
Cosmos Hills Hydro Feasibility
based on the energy and economic modeling, topography, and distance from the existing
road.
In the vicinity of the powerhouse location, Wesley Creek is currently well confined by the
ridge feature several hundred feet high on the west side of the valley which the creek abuts.
There is a low, confining ridge east of the creek that varies from about 1,500 to 2,000 feet
away from the west ridge. It appears that the creek is likely to meander within this valley in
the lower reaches below the proposed powerhouse site.
The powerhouse concept includes a heated and insulated structure situated well above
surrounding grade. The building footprint and size of the foundation for the conceptual
design were driven by the needs of the general arrangement of generation equipment and the
necessary foundation. Structural design parameters for wind, seismic factors, and snow are
moderate, so typical arctic building construction is recommended.
The proposed powerhouse concept utilizes a prefabricated utility building with insulated
wall panel insulation for a complete thermal break. Prefabrication will reduce construction
time in the remote region, as well as provide pre-fitment and complete outfitting of
accessory equipment. The turbine and generator would be installed as a combined unit
before building placement. For maintenance, individual components would be removed
through double man-doors.
6.1.5 Tailrace
Proper design of the tail race is required to ensure that water exiting the turbine returns to
the creek unimpeded. Tail water should return to Wesley Creek by emerging in flowing
water, at a depth below the winter ice cover. Submerging the tail race outlet in the creek
could create problems with clogging due to sedimentation.
The conceptual design for the tail race is to utilize a 36-inch diameter bare HDPE pipe
buried in an insulated trench. The overall length of the tailrace will be approximately 720
linear feet. The pipe should be sized so that it flows approximately half full at the inlet. The
extra capacity is required to allow for entrained air in the water to flow back to the turbine.
The tailrace pipe should be laid at a fairly steep grade to provide a high water velocity at the
discharge point. The high velocity will scour the creek, creating a pool and preventing
sedimentation clogging. The pool will also serve to promote ice cover and prevent clogging
during the winter.
6.1.6 Foundations
The intake facility will be located in an area with potentially alluvial and/or colluvium
deposits, which likely will include boulders. The conceptual design for the intake structure
utilizes a shallow depth reinforced concrete foundation constructed on compacted structural
fill material. The presence of boulders and large diameter colluvium deposits may require a
deeper excavation to remove the large diameter material.
The powerhouse will be located within the creek channel floodplain, so it is likely that the
building site can be located in an area with unfrozen sands and gravels. Therefore, the
Section 6
Alternative Project Descriptions
Feasibility Study and Conceptual Design Report Page 49
Cosmos Hills Hydro Feasibility
conceptual design utilizes a shallow depth reinforced concrete foundation for the building.
The concrete foundation should be constructed on compacted structural fill material. If fine-
grained soils are encountered, they should be removed prior to placement of the structural
fill. Because the powerhouse is within the floodplain, the building should be placed on a
gravel fill embankment constructed to an elevation of approximately 380 feet.
All shallow depth reinforced concrete foundations should incorporate perimeter rigid board
insulation to limit the depth of seasonal frost penetration.
Before actual design of the foundations, site specific geotechnical explorations will be
required to confirm these conceptual design assumptions.
6.1.7 Hydroelectric System
An impulse (Pelton) turbine directly connected to a synchronous generator will be utilized at
Wesley Creek. The switchgear and controls, to be supplied with the turbine, will include a
load governor sized for the peak output and control capabilities for operation in parallel with
the diesel generators or as a standalone system. A head level sensor at the intake will serve
as the primary input for controlling the water flow through the turbine to maintain a
minimum water level at the intake that is just below the spillway height.
A Pelton turbine was selected for optimal operation based on the head, as they are most
efficient under high heads. Pelton turbines consist of an impulse wheel or runner which is
usually a solid disk, or hub, upon which are mounted buckets that are designed to split the
jet and cause it to turn through nearly 170 degrees while sliding over the inner surface as the
bucket travels away from the nozzle. The reaction due to the change of direction delivers
power to the wheel.
Photo 6-2: A Small Single Jet Pelton Turbine
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The expected configuration is a 600 rpm dual nozzle Pelton turbine with a 1,200 rpm
synchronous generator. Additional equipment required as part of the water-to-wire package
includes: gear drive, hydraulic power unit, drive couplings, switchgear and control panels,
inlet valve, dismantling joint, and structural steel equipment mounting frames.
6.1.8 Energy Estimate / Capacity
Energy modeling for the hydroelectric projects takes into account the efficiency of the
turbine and generator, the minimum operating flow, pipeline frictional losses, and water
temperature. Sizing of the turbine and generator was modeled to determine the most
economical capacity for development.
The potential annual energy output for Wesley Creek as a function of the hydraulic capacity
of the feed penstock and the generating system is shown in Exhibit 6-1. For these
projections, an environmental flow rate of 1.2 cfs has been assumed. This volume is 12% of
the average annual flow. Exhibit 6-1 shows that the power output from the power plant
could range from 600,000 kWh per year at 8 cfs capacity to over one million kWh per year
at around 23 cfs capacity. At the design capacity of 15 cfs, the predicted annual power
generation is approximately 1,170,000 kWh.
Exhibit 6-1: Wesley Creek Hydro Energy Potential
6.1.9 Transmission / Distribution Lines
Power will be transmitted to AVEC’s existing Shungnak – Kobuk intertie, located
approximately two miles south of the proposed Wesley Creek powerhouse location. The
transmission line would be strung on wooden poles traversing the distance overland in a
straight line. Tying into the existing system will require a small substation.
0
200,000
400,000
600,000
800,000
1,000,000
1,200,000
1,400,000
1,600,000
8 13 18 23 28Annual Energy Output, kWhHydraulic Capacity (cfs)
Wesley Creek Hydro Potential
Energy Output (no Environmental Flow)
Energy Output (with Environmental Flow)
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The design of the electrical transmission line and substation is outside of this project’s scope
of work. However, conceptual cost estimates have been included in this analysis.
6.1.10 Access Roads
A majority of the project area can be accessed from the existing Bornite Road. A 100-foot-
long, access road will be required from the existing road to the intake facility.
Approximately 4,000 feet south of the Upper Wesley Creek Bridge, the penstock alignment
continues straight while the road begins a large curve. At this point a new approximately
2,500-foot-long access road will be constructed from the Bornite Road to the powerhouse.
The access road and penstock pipeline will follow the same alignment.
Both access roads will be constructed with a surface width of 12 feet. This will provide one-
way traffic during construction and maintenance operations. Pullouts will be spaced
periodically to allow opposing traffic to pass.
Typical embankment construction will consist of one to two feet of compacted gravel over a
geotextile separation fabric. Culverts will be placed where needed.
6.2 Dahl Creek
6.2.1 Characteristics of Dahl Creek
The Dahl Creek project would be a run-of-river project, similar to the Wesley Creek project.
At this location, the upstream basin catchment area is approximately 8.5 square miles. The
project would include a small diversion dam and intake, a long buried penstock pipeline, a
small Turgo turbine and powerhouse, and a tailrace back to the creek. The project would
also include an access road, a transformer, and a high-voltage transmission line.
The only fish observed in Dahl Creek were Dolly Varden. The locations and numbers of
specimens collected during the Aquatic Resources study are shown in Figure 3, located at
the end of this section. Maintaining fish habitat is addressed in Section 8 - Project
Development Issues.
The conceptual design plans for the Dahl Creek Hydro Project are included in Appendix B.
The general arrangement of the project features is described below.
6.2.2 Intake
The intake location, at an elevation of approximately 525 feet, is situated just downstream
from a pond and a small tributary entering Dahl Creek from the east.
The intake at Dahl Creek will be similar in design as the one at Wesley Creek, but slightly
larger. The diversion wall will be approximately the same height, but the intake box
structure will be slightly longer to account for the higher capacity of 16 cfs. Hydraulic
analysis and sediment loading should be completed for this stream during the design phase.
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6.2.3 Penstock
The penstock for the Dahl Creek powerhouse will follow Dahl Creek all the way to the
powerhouse. Two creek crossings will be required because of the narrow valley and the
meanders of the creek.
The conceptual design for the penstock pipeline is 24-inch diameter HDPE pipe buried in an
insulated trench. At creek crossings, the pipe will be insulated and jacketed arctic pipe. The
overall length of the penstock will be approximately 9,000 linear feet. HDPE was selected
over other pipe materials for the same reasons as stated for the Wesley Creek project.
The pipeline size selected for various hydraulic capacities as is shown in the following table
with selection based on limiting head loss to 20% of the static head.
Table 6-2: Dahl Creek - Penstock Diameters and Hydraulic Capacity
Pipe Diameter
(inch)
Max. Flow
(cfs)
18 8
20 9
22 12.5
24 16
26 20
28 24
30 30
6.2.4 Powerhouse
The powerhouse will be located on the west side of Dahl Creek, approximately 1,800 feet
north of the road connecting Bornite Road with the Dahl Creek Airport. The recommended
elevation of the powerhouse is approximately 290 feet. The building structure would be
identical to the previously described Wesley Creek powerhouse.
6.2.5 Tailrace
The design details of the tailrace would be nearly identical to the Wesley Creek project. The
length of the 36-inch diameter HDPE pipe would be approximately 100 linear feet.
6.2.6 Foundations
The design details of the intake and powerhouse facilities would be nearly identical to the
Wesley Creek project. Because the powerhouse will be within the floodplain of Dahl Creek,
the building should be placed on a gravel fill embankment constructed to an elevation of
approximately 290 feet.
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6.2.7 Hydroelectric System
The design details of the hydroelectric system would be nearly identical to the Wesley Creek
project except that the turbine would likely be a Turgo unit due to the lower head. Turgo
turbines are an impulse wheel turbine, similar to the Peltons. However, rather than directing
the water jet directly at a bucket and splitting the flow, in a Turgo turbine, the jet of water
enters the Turgo impulse runner at one side and discharges at the oppose side, falling into
the tailrace by gravity.
The Turgo runner is typically small and yields a higher specific speed for an impulse
turbine. For the Dahl Creek site a single dual nozzle Turgo turbine would be used at 720
rpm. A 1,200 rpm synchronous generator would be used requiring a gear drive, hydraulic
power unit, drive couplings, switchgear and control panels, inlet valve, dismantling joint,
and structural steel equipment mounting frames. If desired, a direct drive option could be
included at an additional cost.
Photo 6-3: A Small Turgo Runner, Deflector Plate, and Nozzle
6.2.8 Energy Estimate / Capacity
Similar to the Wesley Creek project, energy modeling for the hydroelectric projects takes
into account the efficiency of the turbine and generator, the minimum operating flow,
pipeline frictional losses, and water temperature. Sizing of the turbine and generator was
modeled to determine the most economical capacity for development.
The potential annual energy output for Dahl Creek as a function of the hydraulic capacity of
the feed penstock and the generating system is shown in Exhibit 6-2. For these projections,
an environmental flow rate of 1.9 cfs has been assumed. This volume is 12% of the average
annual flow. Exhibit 6-2 shows that the power output from the power plant would be
approximately 1,310,000 kWh per year at 16 cfs capacity.
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Exhibit 6-2: Dahl Creek Hydro Energy Potential
6.2.9 Transmission / Distribution Lines
Power will be transmitted to AVEC’s existing Shungnak – Kobuk intertie, located
approximately 1.5 miles south of the Dahl Creek powerhouse location. The transmission
line would be strung on wooden poles. Tying into the existing system will require a small
substation.
The design of the electrical transmission line and substation is outside of this project’s scope
of work. However, conceptual cost estimates have been included in this analysis.
6.2.10 Access Roads
The access road to the powerhouse will follow an old dirt road/trail alignment that starts on
the access road to the Dahl Creek Airport. The length will be approximately 4,140 feet and
the surface width will be 12 feet. This will provide one-way traffic during construction and
maintenance operations. Pullouts will be spaced periodically to allow opposing traffic to
pass. Typical embankment construction will consist of one to two feet of compacted gravel
over a geotextile separation fabric. Culverts will be placed where needed.
Access to the intake facility will be on the buried penstock alignment. The trench will be
backfilled with gravel material that will be suitable for all-terrain vehicle traffic.
6.3 Kogoluktuk River
6.3.1 Characteristics of the Kogoluktuk River
The Kogoluktuk River project would be a run-of-river project with a small diversion dam
and intake, a long above-ground penstock pipeline, a small Kaplan turbine and powerhouse,
0
200,000
400,000
600,000
800,000
1,000,000
1,200,000
1,400,000
1,600,000
1,800,000
2,000,000
8 13 18 23 28Annual Energy Output, kWhHydraulic Capacity (cfs)
Dahl Creek Hydro Potential
Energy Output (no Environmental Flow)
Energy Output (with Environmental Flow)
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and a tailrace back to the river. The project would also include an access road, a
transformer, and a high-voltage transmission line.
At this location, the upstream basin catchment area is approximately 424 square miles.
The fish observed in the Kogoluktuk River, above the proposed tailrace outfall, included
only Slimy Sculpin and Arctic Grayling. Below the outfall, Chum Salmon, Northern Pike,
Round Whitefish, and Dolly Varden were also observed. The lower cataract appears to be a
barrier to fish passage. The locations and numbers of specimens collected during the
Aquatic Resources study are shown in Figure 4, located at the end of this section.
Maintaining fish habitat is addressed in Section 8 - Project Development Issues.
The conceptual design plans for the Kogoluktuk River Hydro Project are included in
Appendix C. The general arrangement of the project features is described below.
6.3.2 Intake
The intake structure at the Kogoluktuk River would consist of 10-foot-high concrete
diversion walls and intake screens. The intake screens will be installed in a concrete box
structure that directs the flow to the penstock. Two types of intake screens will be utilized:
flat plate fine screens and Coanda screens. The flat plate fine screens will be situated
parallel to the water flow to allow for self-cleaning. The Coanda screens will be installed
perpendicular to the water flow in the portion of the intake structure located at the end of the
diversion wall. The intake portion of the diversion wall is four feet shorter than the portion
of the wall spanning the river and will act as a broad-crested weir.
The screens will be located a minimum of two feet above the stream bed to minimize the
sediment entering the intake structure. The total intake capacity will be 170 cfs with the flat
plate screens sized for 50 cfs and the Coanda screens for 120 cfs. Water will be
continuously diverted for hydro operation and to maintain fluid conditions in the intake,
penstock, and tailrace at all times. The hydroelectric plant is expected to generate power
year-round, although any prescribed environmental flows can significantly impact winter
operation, possibly to the point of curtailing it completely. At flows higher than 170 cfs,
both sets of intake screens would be completely submersed. During the average summer
flows, the intake structure would have approximately five feet of freeboard above the
screens. A more detailed hydraulics analysis may show that constricting the river at the
intake location with the deeper pool and higher velocities could provide the needed flow
year around. This technique is often used with intake designs in colder regions.
The additional height for the diversion wall takes into account an ice cap that will form
during the winter months. During design, the thickness of the ice cap should be verified to
reduce the height of the diversion wall as much as possible. Removal of debris will be
considered at this structure with similar technologies; debris boom, higher velocities, and
diversion of a small percentage of the flows in the river.
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Photo 6-4: Kogoluktuk Intake Site with Obstructing Cliff Downstream
6.3.3 Penstock
The penstock for the Kogoluktuk River powerhouse will follow the Kogoluktuk River, on a
pipe bench cut and/or blasted out of the steep river banks. Pipe burial will not be possible
along most of the alignment. The pipe bench will also serve as the construction road and
access road to the intake, so will be approximately 30 feet wide.
The conceptual design for the penstock pipeline is a 72-inch diameter insulated and jacketed
pipe secured to the pipe bench and/or the rock walls. The overall length of the penstock will
be approximately 4,300 linear feet.
Materials being considered are HDPE, steel, and fiberglass reinforced plastic (FRP). All
materials have the capability to adequately handle the static head. A concern with the
HDPE pipe is the ability to cost effectively fuse the joints on site. A concern with FRP is
the brittle nature of this material at subzero temperatures.
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Photo 6-5: Oblique Aerial of Kogoluktuk Penstock Route
6.3.4 Powerhouse
The powerhouse for the Kogoluktuk River project is not much larger than the Wesley Creek
structure, but will require a larger foundation, two floor levels, a crane, and a taller building.
A pre-engineered metal building is suggested with an outer layer of insulated wall panels
providing a thermal break. Equipment would be installed through a roll up garage door that
would also have hinged insulated wall panels covering the opening.
6.3.5 Tailrace
The tailrace for the Kogoluktuk would be a below grade concrete encased draft tube
transitioning to a concrete box structure that will channel water into dual 6-foot diameter
culverts discharging back to the river. A layer of insulation is included over the water
conveyance.
6.3.6 Foundations
The concrete foundation is expected to be placed directly on excavated bedrock and will
require anchors and a drainage system to reduce potential flotation forces.
Before actual design of the foundations, site specific geotechnical explorations will be
required to confirm these conceptual design assumptions.
6.3.7 Hydroelectric System
A Kaplan turbine was selected, as they perform well under conditions with low head and
high flow. The Kaplan turbine is a propeller type water turbine which has fixed or
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adjustable blades. The ability to alter the inclination of the blades allows the turbine to
adjust to suit the load variations. This provides high efficiencies under considerable
variation of load. A set of wicket gates or vanes controls the flow of water through the unit.
A load governor will be required to limit rapid fluctuations in water flow that could cause
adverse pressure changes in the penstock.
For the Kogoluktuk River project a Kaplan turbine at 600 - 720 rpm would be used. Water-
to-wire equipment would include a synchronous generator, switchgear and control panels,
hydraulic power unit, turbine inlet valve, dismantling joint and associated turbine piping.
Photo 6-6: Large Kaplan Runner with Adjustable Stainless Steel Blades
6.3.8 Energy Estimate / Capacity
The Kaplan turbine has a slightly improved efficiency over the Pelton and Turgo units. The
energy output also incorporates a higher minimum operation flow. For these projections, an
environmental flow rate of 45.0 cfs has been assumed. This volume is 8% of the average
annual flow. Head loss through the large diameter pipeline is generally minimal, except at
the higher flows which reduce energy output as shown in Exhibit 6-3. The power output
from the power plant would be approximately 5,410,000 kWh per year at 170 cfs capacity.
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Exhibit 6-3: Kogoluktuk River Hydro Energy Potential
6.3.9 Transmission / Distribution Lines
Power will be transmitted to AVEC’s existing Shungnak – Kobuk intertie at Kobuk, located
approximately six miles southwest of the proposed Kogoluktuk River powerhouse location.
The transmission line would be strung on wooden poles, following the access road for
approximately half way and directly overland the remaining distance.
The design of the electrical transmission line and substation is outside of this project’s scope
of work. However, conceptual cost estimates have been included in this analysis.
6.3.10 Access Roads
The access road to the powerhouse will begin at the existing road to the Dahl Creek Airport.
The road would parallel the existing runway, on the north side of the airport property,
through Sections 21 and 22. It would then roughly follow the 300-foot elevation contour
through Section 23, avoiding a Native Allotment. Once past the Native Allotment, the road
would drop down to the 250-foot elevation contour through Section 25 and into Section 19.
The road would then cross a ridge in Section 18, traversing up it to approximately elevation
460 feet. Past the ridge, the road would descend down into the Glacier Creek valley to an
elevation of approximately 240 feet. It would then continue to the powerhouse at the
northern edge of Section 17. Access to the intake facility will be along the penstock
alignment bench, adjacent to the Kogoluktuk River.
The length of the access road will be approximately 32,000 feet (6 miles). The surface
width will be 12 feet. This will provide one-way traffic during construction and
maintenance operations. Pullouts will be spaced periodically to allow opposing traffic to
pass. Typical embankment construction will consist of one to two feet of compacted gravel
over a geotextile separation fabric. Culverts will be placed where needed.
0
1,000,000
2,000,000
3,000,000
4,000,000
5,000,000
6,000,000
7,000,000
8,000,000
9,000,000
80 130 180 230 280Annual Energy Output, kWhHydraulic Capacity (cfs)
Kogoluktuk River Hydro Potential
Energy Output (no Environmental Flow)
Energy Output (with Environmental Flow)
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6.4 Hydroelectric Capacity Selection
The economic modeling developed for this study utilizes hydro capacity, power demand,
load growth, and turbine operation cutoff flows to determine the amount of diesel electric
generation displaced. Capacity selection requires an analysis of the power demand and the
water resources available (Wesley Creek, Dahl Creek, and Kogoluktuk River; with and
without environmental flows; seasonal flows, available head, penstock diameters). Power
demand and load growth requires an analysis of the load combination scenarios (with and
without an Ambler intertie, growth rates). The capacity also affects the turbine cutoff flow;
as capacity increases, the cutoff flow increases, while the displaced diesel generation
decreases due to a shorter hydropower generation season. These parameters are inter-related
and require an iterative approach to the analysis.
The following project configurations and energy potential (without potential environmental
flows) are recommended based on analysis:
Table 6-3: Hydro Project Detailed Configuration
Parameter Wesley Dahl Kogoluktuk
Hydrology
Basin Area (sq mi) 5.24 8.50 424
Avg. Annual Flow (cfs) 9.8 15.9 558
Minimum Flow (cfs) 1.4 2.3 73.4
Environmental Flow 1.2 1.9 45.0
Configuration
Design Flow (cfs) 15 16 170
Min Operation Flow 1.5 1.6 25.5
Intake Elevation (ft) 667 537 235
Tailwater/Powerhouse Elevation (ft) 375 280 171
Static Head (ft) 292 257 64
Penstock OD (in) 24 24 72
Penstock Length (ft) 7,750 9,000 4,300
Velocity (fps) 5.7 5.1 6.0
Friction Loss (ft) 35 39 5.8
Friction Loss % 12% 15% 9%
Generator Efficiency 94% 94% 94%
Transmission Efficiency 95% 95% 95%
Peak Turbine Efficiency 89% 89% 92%
Net Efficiency (including transmission) 79% 79% 82%
Output
Capacity (kW) 260 235 690
Annual Energy (kWh) 1,170,000 1,310,000 5,410,000
Annual Energy w/ Environmental Flows (kWh) 880,000 1,030,000 3,800,000
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Section 7
Life-Cycle Cost Analysis
Feasibility Study and Conceptual Design Report Page 67
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7. LIFE-CYCLE COST ANALYSIS
7.1 Displaced Diesel Electric Generation
Displaced diesel generation is determined as follows:
• Modeling was performed using daily stream flows and daily demand consisting of
peak and average load derived from 15-minute interval energy data.
• Water availability for power is determined from the median daily hydrology less in-
stream environmental flows, if any. If the available water is less than the minimum
flow required by the turbine, then no power is produced by the hydro.
• Hydropower potential output is calculated using the dynamic head and turbine
efficiency for the given flow and the fixed efficiencies for the generator and
transmission.
• The required diesel fuel for diesel electric generation is calculated for each day based
on the average energy need for each day and a diesel generation efficiency based on
the average from the FY 2012 PCE report.
• Hydro output is compared with energy needs, as follows, to determine the required
diesel generation, the hydro penetration into demand, and the available hydro energy
for heat.
• If the daily 15 minute peak demand plus a 15 kW buffer exceeds the hydro
output, then a diesel is required to run at the minimum diesel loading (40.4 kW)
for 12 hours.
• If the daily average demand exceeds the hydro output, then a diesel is required to
provide the greater of at least 24 hours of energy at the minimum loading or the
remainder of energy needs after subtracting the hydro output.
• The hydropower for displacement of diesel energy is calculated after subtracting
the required diesel energy.
• Any remaining hydro energy is considered available for heating up to the
maximum amount of heating energy required.
• All the outputs for each day of the year are summed to provide an expected average
annual performance scenario for economic analysis.
The displaced diesel generation for each of the three individual hydroelectric projects,
without potential environmental flows, is shown in the operational charts in the Project
Summary section 7.4 below.
7.2 Project Development Costs
Because barges will likely not be available to reach Kobuk, all materials, construction
equipment, and supplies for the hydro project construction are assumed to require air
delivery. A summary of the development costs are shown in the following sections.
Section 7
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Feasibility Study and Conceptual Design Report Page 68
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7.2.1 Wesley Creek
The total cost to design and construct the Wesley Creek hydro project is estimated to be
$13.6M, as shown below. This estimate is based on the conceptual-level design plans
included in Appendix A. A detailed breakdown of the construction cost is included in
Appendix D.
Table 7-1: Wesley Creek Project - Conceptual-Level Development Cost Estimate
Item Description Cost
Mobilization $1,900,000
Diversion and Intake Structures $1,230,000
Penstock $2,299,000
Tailrace $331,000
Power House and Hydroelectric System $1,575,000
Access Road $330,000
Electrical Transmission $926,000
Miscellaneous Items $225,000
Construction Subtotal $8,816,000
Bonding and Insurance $441,000
Construction Engineering and Administration $926,000
25% Contingency $2,546,000
Total Construction Project Cost $12,728,000
Preconstruction Costs (Survey, Geotechnical,
Environmental, Design, Permitting $891,000
Total Development Costs $13,619,000
Section 7
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Feasibility Study and Conceptual Design Report Page 69
Cosmos Hills Hydro Feasibility
7.2.2 Dahl Creek
The total cost to design and construct the Dahl Creek hydro project is estimated to be
$15.2M, as shown below. This estimate is based on the conceptual-level design plans
included in Appendix B. A detailed breakdown of the construction cost is included in
Appendix D.
Table 7-2: Dahl Creek Project - Conceptual-Level Development Cost Estimate
Item Description Cost
Mobilization $1,960,000
Diversion and Intake Structures $1,480,000
Penstock $2,658,000
Tailrace $44,000
Power House and Hydroelectric System $1,675,000
Access Road $902,000
Electrical Transmission $926,000
Miscellaneous Items $225,000
Construction Subtotal $9,870,000
Bonding and Insurance $493,000
Construction Engineering and Administration $1,036,000
25% Contingency $2,850,000
Total Construction Project Cost $14,249,000
Preconstruction Costs (Survey, Geotechnical,
Environmental, Design, Permitting $998,000
Total Development Costs $15,247,000
Section 7
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Feasibility Study and Conceptual Design Report Page 70
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7.2.3 Combined Wesley Creek and Dahl Creek
The total cost to design and construct the combined Wesley Creek and Dahl Creek hydro
project is estimated to be $26.0M, as shown below. This estimate is based on the
conceptual-level design plans included in Appendices A and B. A detailed breakdown of
the construction cost is included in Appendix D.
Table 7-3: Combined Wesley Creek / Dahl Creek Project -
Conceptual-Level Development Cost Estimate
Item Description Cost
Mobilization $2,685,000
Diversion and Intake Structures $2,710,000
Penstock $4,957,000
Tailrace $376,000
Power House and Hydroelectric System $3,250,000
Access Road $1,231,000
Electrical Transmission $1,852,000
Miscellaneous Items $425,000
Construction Subtotal $17,486,000
Bonding and Insurance $874,000
Construction Engineering and Administration $1,102,000
25% Contingency $4,865,000
Total Construction Project Cost $24,327,000
Preconstruction Costs (Survey, Geotechnical,
Environmental, Design, Permitting $1,703,000
Total Development Costs $26,030,000
Section 7
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Feasibility Study and Conceptual Design Report Page 71
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7.2.4 Kogoluktuk River
The total cost to design and construct the Kogoluktuk River hydro project is estimated to be
$38.7M, as shown below. This estimate is based on the conceptual-level design plans
included in Appendix C. A detailed breakdown of the construction cost is included in
Appendix D.
Table 7-4: Kogoluktuk River Project - Conceptual-Level Development Cost Estimate
Item Description Cost
Mobilization $2,340,000
Diversion and Intake Structures $3,200,000
Penstock $9,860,000
Tailrace $140,000
Power House and Hydroelectric System $3,300,000
Access Road $4,038,000
Electrical Transmission $2,974,000
Miscellaneous Items $275,000
Construction Subtotal $26,127,000
Bonding and Insurance $1,306,000
Construction Engineering and Administration $1,097,000
25% Contingency $7,133,000
Total Construction Project Cost $35,663,000
Preconstruction Costs (Survey, Geotechnical,
Environmental, Design, Permitting $2,997,000
Total Development Costs $38,660,000
Section 7
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Feasibility Study and Conceptual Design Report Page 72
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7.2.5 Operation and Maintenance (O&M) Costs
Operation and Maintenance (O&M) costs for the hydro projects are estimated on an
annualized basis at the rate of 0.5% of the total project cost. The breakdown by project is
shown below.
Table 7-5: Operations and Maintenance Costs
Project Annual Cost
Wesley Creek $68,100
Dahl Creek $76,200
Combined Wesley Creek and Dahl Creek $130,100
Kogoluktuk River $193,300
7.3 Lifecycle Evaluation
7.3.1 Economic Analysis
The results of the operational model were used to compare the proposed alternative electric
generation scenarios and determine which development scenarios were beneficial. The
following summarizes the general assumptions and basic modeling methods that were used
to determine the net project benefits and costs.
Economic Assumptions
• 2013 Dollars. All numbers are reported in 2013 dollars.
• Discount Rate. A discount rate of 2.5% was selected to discount future benefits to
2013 dollars. The selection of the discount rate is based on the recently completed
Southeast Integrated Resource Plan prepared by Black and Veatch for AEA.
• Term of Analysis. The term of analysis is 50 years, consistent with other AEA hydro
analyses.
• Ambler Intertie Benefits. The construction of the intertie results in reduced diesel
O&M (one plant running instead of two), reduced fuel cost (less fuel delivered by
air), and reduced capital expenditures for plant replacements (only one plant in
Ambler to periodically replace). These savings are applied to the diesel-only case of
generation. Subsequent savings from hydro is determined from this intertie
improved base case.
The cost for new diesel plants and bulk fuel facilities in Ambler and Shungnak is
estimated as $12 million for each community.
• Environmental Flows. Permitting agencies may require a minimum flow be released
over a project’s diversion dam to maintain water levels in the stream between the
intake and tailrace. The flows could be required to support fish in that area or for
other environmental purposes. These flows would decrease the water available to
the hydro projects. Until detailed permitting and design is completed, the required
environmental flow for each project, if any, is unknown. Yet the flows have a
Section 7
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Feasibility Study and Conceptual Design Report Page 73
Cosmos Hills Hydro Feasibility
significant effect on project economics. They decrease the water available for the
project, decrease the electricity output, and decrease project benefits.
For this analysis, the economic benefits are modeled in two ways: first, assuming no
required environmental flow; and second, assuming environmental flows as
described in section 6. While the analysis presents results using two scenarios
with and without environmental flows the actual required number could be
between those two, or perhaps more than what was modeled. If appropriate
mitigation were found, perhaps no environmental flows would be required.
Load Assumptions
• Conservative Load Growth Assumed. The analysis assumes a 1% continuous load
growth. This is a conservative assumption for a number of reasons. For the last five
years, electric load has grown faster than this report projects. It has grown at 1.4%
(see Table 5-4). Also, the hydro projects would decrease electricity costs. The
analysis does not assume that the decreased cost causes additional demand. Finally,
these villages are relatively poor. While most households have water and sewer, a
few still haul water or use a “honey bucket” (See Section 3.5). Electricity use in
these villages is low by typical American standards. A 1% electric growth rate
means that in 50 years, village use will still be below typical 2013 American use,
even for rural communities. This low load growth is consistent with the villages
remaining relatively poor with few services for 50 years. It is difficult to believe that
the villages will remain in place essentially unchanged for 50 years.
Despite these issues, the analysis uses a conservative 1% growth rate to ensure that it
does not over predict benefits. A higher growth rate would increase the benefits of
the projects (primarily the Kogoluktuk, which has significantly more energy
potential).
• Existing and Likely Mineral Exploration Load Excluded. NANA and NovaCopper,
Inc. are exploring for minerals in the region of the potential hydro projects. Both
companies have indicated that if hydro projects are constructed and the villages have
excess hydro capacity, the exploration operation would make use of the electricity.
Thus, mineral exploration has potential to add significant electric load. While the
existing mineral exploration could end at any time, the region has been explored off
and on for many decades. There is no reason to believe that even if this exploration
operation ends, that periodic mineral exploration will suddenly stop. Given NANA’s
aggressive marketing of its property and the historic interest in the area, it is likely
that this mineral district – like others across the state – will see continued, if perhaps
periodic, mineral exploration during the 50-year time horizon of the economic
analysis. If so, the exploration is likely to add significantly to the projected loads.
Including potential estimates of these loads would increase the benefits of the hydro
projects, especially for the Kogoluktuk Project. However, the timing and amount of
the electric needs over the 50-year horizon is unknown. Therefore, potential mineral
exploration load increases are excluded from the analysis. Given the likelihood of at
least periodic mineral exploration over the 50-year horizon, the loads used in this
analysis likely under predict the true electric load, at least during some years.
Section 7
Life-Cycle Cost Analysis
Feasibility Study and Conceptual Design Report Page 74
Cosmos Hills Hydro Feasibility
• Speculative Mineral Development and Road-induced Load Growth Excluded. It is
possible that an actual mine may be developed in the region. In addition, Alaska’s
roads-to-resources program is planning for a road in the region. Both would increase
electric loads in the region. However, both developments are speculative at this
point. For that reason, electric demand that would be created by mining
development or from a regional road is excluded from the analysis.
Fuel Price Assumptions
• The analysis uses fuel prices from ISER Medium and High Case. As explained in
Section 5.3.1, the ISER projections likely under predict fuel prices because they are
based on a historic ratio of barge/air fuel delivery. Unfortunately, that ratio has
changed and fuel prices will therefore be significantly higher. The AVEC 2013 case
is intended to rectify this issue.
Electricity for Heat Assumptions
• From mid-May through December, the Kogoluktuk Project can generate much more
electricity than the communities can use. At the same time, community facilities
such as the water/sewer system and the washeteria are burning fuel oil for heat.
The excess electric generating capacity can be used as an interruptible power source
for that electric heat.
• The analysis of electric heat assumes that an electric boiler system costs $250,000
and that one would be installed in each community connected to the hydro.
• The maximum utilization of heat energy is limited to 50% of the heat demand as
defined by the Heating Degree Day climate data from Bettles and the annual heating
fuel usage in the AEA 2010 Energy Pathway.
• The benefit of heat utilization from the diesel plant is also included in the modeling.
Waste heat available from diesel electric generation is calculated as 20% of electric
demand. The diesel waste heat energy is also included when a diesel is required to
supplement hydro energy.
• Where heat is included in the results tables, the benefit of the hydro heat value is
determined after subtracting the diesel only heat value and then dividing by the
hydro cost plus the electric boiler cost.
For each hydro project, the economic analysis analyzes 12 scenarios: three alternative fuel
cases, two environmental flows (with and without required by-pass flows), and two intertie
connections (with and without the Ambler Intertie). These scenarios were analyzed using
the daily operational model to determine the annual savings provided by the development
over the analysis term. Two tables below show the information needed to construct the
benefit/cost ratio. Table 7-6 shows the Net Present Value of the hydro projects’ savings,
excluding heating value, for each scenario.
Table 7-7 shows the Net Present Cost of each project.
Section 7
Life-Cycle Cost Analysis
Feasibility Study and Conceptual Design Report Page 75
Cosmos Hills Hydro Feasibility
Table 7-6: Net Present Value of Hydro Project Benefits, Millions of 2013 $
Fuel Case Environmental
Flow Intertie Wesley Dahl Wesley
plus Dahl Kogoluktuk
ISER Medium No No 14.2 16.1 20.6 33.8
ISER High No No 19.6 22.2 28.3 46.4
AVEC No No 18.5 21.0 26.7 43.7
ISER Medium Yes No 12.5 13.6 16.7 28.0
ISER High Yes No 17.2 18.7 22.9 38.5
AVEC Yes No 16.2 17.6 21.6 36.2
ISER Medium No Yes 14.4 16.1 23.9 42.7
ISER High No Yes 19.5 21.8 32.2 57.5
AVEC No Yes 20.1 22.4 32.8 58.7
ISER Medium Yes Yes 12.9 14.0 20.6 34.5
ISER High Yes Yes 17.4 18.9 27.6 46.4
AVEC Yes Yes 17.9 19.5 28.1 47.3
Table 7-7: Net Present Value of Hydro Project Cost, Millions of 2013 $
Fuel Case Environmental
Flow Intertie Wesley Dahl Wesley
plus Dahl Kogoluktuk
ISER Medium No No 13.7 15.3 26.1 37.8
ISER High No No 13.7 15.3 26.1 37.8
AVEC No No 13.7 15.3 26.1 37.8
ISER Medium Yes No 13.7 15.3 26.1 37.8
ISER High Yes No 13.7 15.3 26.1 37.8
AVEC Yes No 13.7 15.3 26.1 37.8
ISER Medium No Yes 13.7 15.3 26.1 37.8
ISER High No Yes 13.7 15.3 26.1 37.8
AVEC No Yes 13.7 15.3 26.1 37.8
ISER Medium Yes Yes 13.7 15.3 26.1 37.8
ISER High Yes Yes 13.7 15.3 26.1 37.8
AVEC Yes Yes 13.7 15.3 26.1 37.8
7.3.2 Project Comparison
The tables below show the economic conclusions for the 12 project scenarios. Conclusions
are shown in three ways: benefit/cost ratio, net present cost of power, and net present cost of
power (per kWh). The three methods present three different viewpoints on project benefits.
Benefit/Cost Ratio presents the results from the viewpoint of an investor. Are the benefits
greater than the cost (i.e., B/C >1)? If so, which project returns the best multiple for each
dollar invested? The Net Present Cost of Power is different. The Net Present Cost of Power
Section 7
Life-Cycle Cost Analysis
Feasibility Study and Conceptual Design Report Page 76
Cosmos Hills Hydro Feasibility
presents the results from the viewpoint of a consumer. Which of the projects (including
diesel – the no hydro alternative) provides the lowest cost of power?
Table 7-8: Hydro Project Benefit to Cost Ratios (Electricity Only)
Fuel Case Environmental
Flow Intertie Wesley Dahl Wesley
plus Dahl Kogoluktuk
ISER Medium No No 1.04 1.05 0.79 0.89
ISER High No No 1.44 1.46 1.09 1.23
AVEC No No 1.35 1.37 1.02 1.16
ISER Medium Yes No 0.92 0.89 0.64 0.74
ISER High Yes No 1.26 1.22 0.88 1.02
AVEC Yes No 1.19 1.15 0.83 0.96
ISER Medium No Yes 1.06 1.05 0.92 1.13
ISER High No Yes 1.43 1.42 1.23 1.52
AVEC No Yes 1.47 1.46 1.26 1.55
ISER Medium Yes Yes 0.94 0.92 0.79 0.91
ISER High Yes Yes 1.28 1.24 1.06 1.23
AVEC Yes Yes 1.31 1.27 1.08 1.25
Table 7-9: Net Present Cost of Electric Generation, Millions of 2013 $
Fuel Case Environ.
Flow Intertie NPC
Diesel Wesley Dahl Wesley
plus Dahl Kogoluktuk
ISER Medium No No 104.5 103.9 103.6 109.9 108.4
ISER High No No 127.0 121.0 120.0 124.7 118.3
AVEC No No 125.1 120.2 119.4 124.5 119.2
ISER Medium Yes No 104.5 105.6 106.2 113.8 114.2
ISER High Yes No 127.0 123.4 123.6 130.1 126.2
AVEC Yes No 125.1 122.5 122.7 129.6 126.6
ISER Medium No Yes 94.1 93.3 93.3 96.2 89.1
ISER High No Yes 112.4 106.5 105.9 106.3 92.6
AVEC No Yes 114.4 108.0 107.3 107.7 93.4
ISER Medium Yes Yes 94.1 94.8 95.4 99.6 97.4
ISER High Yes Yes 112.4 108.6 108.8 110.9 103.8
AVEC Yes Yes 114.4 110.1 110.2 112.4 104.9
Section 7
Life-Cycle Cost Analysis
Feasibility Study and Conceptual Design Report Page 77
Cosmos Hills Hydro Feasibility
Table 7-10: Net Present Cost of Electric Generation, 2013 $ per kWh
Fuel Case Environ.
Flow Intertie NPC
Diesel Wesley Dahl Wesley
plus Dahl Kogoluktuk
ISER Medium No No 0.55 0.55 0.55 0.58 0.57
ISER High No No 0.67 0.64 0.63 0.66 0.62
AVEC No No 0.66 0.64 0.63 0.66 0.63
ISER Medium Yes No 0.55 0.56 0.56 0.60 0.60
ISER High Yes No 0.67 0.65 0.65 0.69 0.67
AVEC Yes No 0.66 0.65 0.65 0.68 0.67
ISER Medium No Yes 0.50 0.49 0.49 0.51 0.47
ISER High No Yes 0.59 0.56 0.56 0.56 0.49
AVEC No Yes 0.60 0.57 0.57 0.57 0.49
ISER Medium Yes Yes 0.50 0.50 0.50 0.53 0.51
ISER High Yes Yes 0.59 0.57 0.57 0.59 0.55
AVEC Yes Yes 0.60 0.58 0.58 0.59 0.55
The three tables show that a hydro project is the best alternative for 10 of the 12 scenarios.
The only two scenarios where diesel remains the best alternative is for the ISER Medium
fuel case with required environmental flows, both with and without an intertie. Also, the
combination project that includes both Wesley and Dahl Creeks is never the best alternative.
The tables also show the importance of environmental flows. The required environmental
flows increase the Net Cost of Power and decrease Benefit/Cost ratios. This conclusion is
true even for scenarios where the project remains economically viable with environmental
flows. Unfortunately, the actual agency-required environmental flows will not be known
until permitting is finished. Agencies could require a lower volume than the economic
model assumes, or possible a higher volume. It is even possible that if appropriate
mitigation were found, no environmental flow would be required.
Table 7-8, Benefit/Cost Ratios, shows that if the Ambler Intertie is not constructed the Dahl
or Wesley project has the highest Benefit/Cost ratio. The Kogoluktuk has a lower
benefit/cost ratio than the other two projects if the intertie is not constructed and
environmental flows are required. That is not a surprising conclusion. The Kogoluktuk is a
larger project and is best with a larger load: i.e., the Ambler Intertie.
Table 7-9 and Table 7-10 describe the Net Present Cost of Power. The tables compare the
projects from a consumer point of view – which one has the lowest cost of power. That is
why these tables include the cost of power for continued diesel generation. From this
viewpoint, the Wesley or Dahl Creek project produces the lowest power cost in 3 of the 12
scenarios. The Kogoluktuk River project produces the lowest power cost in 7 of the
scenarios. Diesel would be the least expensive in 2 of the scenarios. (It should be noted that
Table 7-10 does not necessarily reflect the actual cost to the consumer, as no allowances for
Section 7
Life-Cycle Cost Analysis
Feasibility Study and Conceptual Design Report Page 78
Cosmos Hills Hydro Feasibility
PCE or grants have been accounted for. It is based on the net present cost of generation
divided by the total electric demand.)
Finally, the tables model conservative economic assumptions. They assume a 1% load
growth even though the most recent five years for the three villages show a growth rate that
is 40% higher (1.4%). The load growth is conservative in that it excludes the potential for
mineral exploration, even though periodic mineral exploration has occurred in the area for
the last few decades and is expected at least periodically in the future, even if the current
exploration ceases.
In addition, the model includes an analysis of the value of utilizing energy for heating
purposes. All three hydro projects have some periods of the year when they can produce
electricity in excess of electric demand. An operating diesel plant also has excess heat
available from the cooling system.
Utilizing heat energy can add significant value in the form of the avoided cost of heating oil
used. Table 7-11 describes the effect of including the heat value of energy available for
heating uses. The tables use a heating fuel price of $7/gallon in Ambler and $10/gallon for
Shungnak and Kobuk. The price is escalated at the same rate as the fuel oil case. An 85%
conversion efficiency of fuel oil stoves is used when considering offset benefits. Given
these parameters, the value of avoided space heat is $0.21/kWh in Ambler and $0.30/kWh in
Shungnak.
Table 7-111: Net Present Value of Using “Excess” Electricity for Heat, Millions of 2013 $
Fuel Case Environ.
Flow Intertie Diesel Wesley Dahl Wesley
plus Dahl Kogoluktuk
ISER Medium No No 7.8 5.0 4.8 6.2 13.5
ISER High No No 10.4 6.5 6.4 8.2 18.0
AVEC No No 8.9 5.6 5.5 7.0 15.3
ISER Medium Yes No 7.8 5.1 5.1 6.4 9.7
ISER High Yes No 10.4 6.7 6.7 8.5 13.0
AVEC Yes No 8.9 5.8 5.8 7.3 11.1
ISER Medium No Yes 4.0 4.4 4.2 6.3 8.4
ISER High No Yes 5.3 5.8 5.5 8.3 11.1
AVEC No Yes 4.6 5.0 4.8 7.1 9.5
ISER Medium Yes Yes 4.0 4.6 4.4 6.5 8.2
ISER High Yes Yes 5.3 6.0 5.8 8.7 10.9
AVEC Yes Yes 4.6 5.2 5.0 7.4 9.3
The table shows that the additional heat value of this otherwise excess electricity has
significant economic value. Interruptible electric heat can be used by community facilities
such as the water/sewer system and the washeteria. If there is enough available, it could be
used as interruptible space heat for facilities and residences.
Section 7
Life-Cycle Cost Analysis
Feasibility Study and Conceptual Design Report Page 79
Cosmos Hills Hydro Feasibility
Not surprisingly, the Kogoluktuk can produce much greater heating value than the other two
projects. The table also shows that if, as expected, the Ambler Intertie is constructed, the
electric load uses essentially all the electricity from the two smaller projects. The
Kogoluktuk project is much larger. It produces a lot of electricity that is excess to the
communities’ consumption, even with the Ambler Intertie.
Table 7-12 shows the effect of heat value on the Benefit/Cost ratios.
Table 7-12: Hydro Project Benefit to Cost Ratios (including the Heat Value of Electricity)
Fuel Case
Environmental
Flow Intertie Wesley Dahl Wesley
plus Dahl Kogoluktuk
ISER Medium No No 0.80 0.83 0.71 1.03
ISER High No No 1.11 1.15 0.98 1.41
AVEC No No 1.07 1.11 0.93 1.31
ISER Medium Yes No 0.69 0.69 0.57 0.78
ISER High Yes No 0.95 0.95 0.79 1.07
AVEC Yes No 0.92 0.92 0.75 1.00
ISER Medium No Yes 1.03 1.01 0.98 1.22
ISER High No Yes 1.39 1.37 1.31 1.64
AVEC No Yes 1.42 1.41 1.32 1.65
ISER Medium Yes Yes 0.93 0.90 0.86 1.00
ISER High Yes Yes 1.26 1.21 1.15 1.35
AVEC Yes Yes 1.29 1.24 1.15 1.35
The table shows some interesting impacts to the project Benefit to Cost ratios when heat
utilization is included. The Wesley and Dahl hydro projects (without the intertie) actually
have reduced benefit to cost ratios, due to the heat recovery available from the diesel plants.
As expected, though, the economics of the Kogoluktuk project improve for all cases.
7.4 Project Summary
A sampling of the Life Cycle Project Summary sheets, detailing the costs, benefits, and FY
2013 daily operational chart of each project, are shown below. These particular summaries
are for the scenarios with the Ambler-Shungnak intertie, with and without potential
environmental flows, AVEC fuel cost, and utilizing excess heat. The tables above were
derived from these summaries.
Section 7
Life-Cycle Cost Analysis
Feasibility Study and Conceptual Design Report Page 80
Cosmos Hills Hydro Feasibility
Exhibit 7-1: Wesley Creek Hydroelectric Project Summary
Development Scheme
Design Flow 15 cfs
Static Head 292 ft
Installed hydro capacity 260 kW
Annual Energy Potential 1,170,000 kWh
Design/Permitting Start 7/1/2014
Project Online Date 7/1/2018
Total Installed Cost $14,370,000
Annual O&M Cost $68,100
Net Present Cost (NPC 2013) $14,400,000 50 yr term, 2.5% discount rate
Resultant Cost Savings FY 2013 (year 0) FY 2038 (year 25) FY 2063 (year 50)
Energy Demand, kWh 2,936,651 3,766,056 4,829,710
Displaced Diesel Energy, kWh 1,066,977 1,168,001 1,169,836
Hydro Penetration 36% 31% 24%
Displaced Diesel Fuel, gal 76,267 87,379 88,609
Displaced Fuel Value (2013 $) $537,959 $465,755 $387,317
Displaced Nonfuel Value (2013 $) $11,856 $0 $0
Estimated Displaced Heat Energy, kWh 473,661 521,446 727,818
Net Present Value (NPV 2013) $20,477,686 50 yr term, 2.5% discount rate
Benefit to Cost Ratio 1.42
Wesley, Ambler-Shungnak Intertie Constructed, No Environmental Flows, AVEC Fuel Case, heat included
0
200
400
600
800
1000
1200
1400
1600
1800
2000
9/1 10/1 11/1 12/1 1/1 2/1 3/1 4/1 5/1 6/1 7/1 8/1Power (kW)Day of Year
Operational Chart, FY 2013 Diesel for Heat with Hydro
Hydro + Diesel for Heat, kW
Diesel for Electricity
Hydropower for Electricity
Hydropower Output
Electrical Demand
Heat + Electrical Demand
Section 7
Life-Cycle Cost Analysis
Feasibility Study and Conceptual Design Report Page 81
Cosmos Hills Hydro Feasibility
Development Scheme
Design Flow 15 cfs
Static Head 292 ft
Installed hydro capacity 260 kW
Annual Energy Potential 1,040,000 kWh
Design/Permitting Start 7/1/2014
Project Online Date 7/1/2018
Total Installed Cost $14,370,000
Annual O&M Cost $68,100
Net Present Cost (NPC 2013) $14,400,000 50 yr term, 2.5% discount rate
Resultant Cost Savings FY 2013 (year 0) FY 2038 (year 25) FY 2063 (year 50)
Energy Demand, kWh 2,936,651 3,766,056 4,829,710
Displaced Diesel Energy, kWh 947,860 1,038,112 1,039,647
Hydro Penetration 32% 28% 22%
Displaced Diesel Fuel, gal 67,753 78,094 79,303
Displaced Fuel Value (2013 $) $477,901 $416,266 $346,640
Displaced Nonfuel Value (2013 $) $9,576 $0 $0
Estimated Displaced Heat Energy, kWh 487,554 547,107 751,582
Net Present Value (NPV 2013) $18,527,266 50 yr term, 2.5% discount rate
Benefit to Cost Ratio 1.29
Wesley, Ambler-Shungnak Intertie Constructed, Environmental Flows Required, AVEC Fuel Case, heat included
0
200
400
600
800
1000
1200
1400
1600
1800
2000
9/1 10/1 11/1 12/1 1/1 2/1 3/1 4/1 5/1 6/1 7/1 8/1Power (kW)Day of Year
Operational Chart, FY 2013 Diesel for Heat with Hydro
Hydro + Diesel for Heat, kW
Diesel for Electricity
Hydropower for Electricity
Hydropower Output
Electrical Demand
Heat + Electrical Demand
Section 7
Life-Cycle Cost Analysis
Feasibility Study and Conceptual Design Report Page 82
Cosmos Hills Hydro Feasibility
Exhibit 7-2: Dahl Creek Hydroelectric Project Summary
Development Scheme
Design Flow 16 cfs
Static Head 257 ft
Installed hydro capacity 240 kW
Annual Energy Potential 1,310,000 kWh
Design/Permitting Start 7/1/2014
Project Online Date 7/1/2018
Total Installed Cost $16,000,000
Annual O&M Cost $76,200
Net Present Cost (NPC 2013) $16,030,000 50 yr term, 2.5% discount rate
Resultant Cost Savings FY 2013 (year 0) FY 2038 (year 25) FY 2063 (year 50)
Energy Demand, kWh 2,936,651 3,766,056 4,829,710
Displaced Diesel Energy, kWh 1,214,626 1,306,923 1,308,217
Hydro Penetration 41% 35% 27%
Displaced Diesel Fuel, gal 86,821 97,309 98,500
Displaced Fuel Value (2013 $) $612,402 $518,685 $430,553
Displaced Nonfuel Value (2013 $) $13,452 $0 $0
Estimated Displaced Heat Energy, kWh 435,796 493,120 701,826
Net Present Value (NPV 2013) $22,572,462 50 yr term, 2.5% discount rate
Benefit to Cost Ratio 1.41
Dahl, Ambler-Shungnak Intertie Constructed, No Environmental Flows, AVEC Fuel Case, heat included
0
200
400
600
800
1000
1200
1400
1600
1800
2000
9/1 10/1 11/1 12/1 1/1 2/1 3/1 4/1 5/1 6/1 7/1 8/1Power (kW)Day of Year
Operational Chart, FY 2013 Diesel for Heat with Hydro
Hydro + Diesel for Heat, kW
Diesel for Electricity
Hydropower for Electricity
Hydropower Output
Electrical Demand
Heat + Electrical Demand
Section 7
Life-Cycle Cost Analysis
Feasibility Study and Conceptual Design Report Page 83
Cosmos Hills Hydro Feasibility
Development Scheme
Design Flow 16 cfs
Static Head 257 ft
Installed hydro capacity 240 kW
Annual Energy Potential 1,130,000 kWh
Design/Permitting Start 7/1/2014
Project Online Date 7/1/2018
Total Installed Cost $16,000,000
Annual O&M Cost $76,200
Net Present Cost (NPC 2013) $16,030,000 50 yr term, 2.5% discount rate
Resultant Cost Savings FY 2013 (year 0) FY 2038 (year 25) FY 2063 (year 50)
Energy Demand, kWh 2,936,651 3,766,056 4,829,710
Displaced Diesel Energy, kWh 1,038,387 1,130,618 1,131,897
Hydro Penetration 35% 30% 23%
Displaced Diesel Fuel, gal 74,223 84,707 85,897
Displaced Fuel Value (2013 $) $523,544 $451,511 $375,463
Displaced Nonfuel Value (2013 $) $13,452 $0 $0
Estimated Displaced Heat Energy, kWh 470,963 528,367 737,083
Net Present Value (NPV 2013) $19,919,874 50 yr term, 2.5% discount rate
Benefit to Cost Ratio 1.24
Dahl, Ambler-Shungnak Intertie Constructed, Environmental Flows Required, AVEC Fuel Case, heat included
0
200
400
600
800
1000
1200
1400
1600
1800
2000
9/1 10/1 11/1 12/1 1/1 2/1 3/1 4/1 5/1 6/1 7/1 8/1Power (kW)Day of Year
Operational Chart, FY 2013 Diesel for Heat with Hydro
Hydro + Diesel for Heat, kW
Diesel for Electricity
Hydropower for Electricity
Hydropower Output
Electrical Demand
Heat + Electrical Demand
Section 7
Life-Cycle Cost Analysis
Feasibility Study and Conceptual Design Report Page 84
Cosmos Hills Hydro Feasibility
Exhibit 7-3: Wesley + Dahl Hydroelectric Project Summary
Development Scheme
Design Flow #N/A cfs
Static Head #N/A ft
Installed hydro capacity 500 kW
Annual Energy Potential 2,480,000 kWh
Design/Permitting Start 7/1/2014
Project Online Date 7/1/2018
Total Installed Cost $26,780,000
Annual O&M Cost $130,100
Net Present Cost (NPC 2013) $26,840,000 50 yr term, 2.5% discount rate
Resultant Cost Savings FY 2013 (year 0) FY 2038 (year 25) FY 2063 (year 50)
Energy Demand, kWh 2,936,651 3,766,056 4,829,710
Displaced Diesel Energy, kWh 1,561,588 1,818,422 2,033,602
Hydro Penetration 53% 48% 42%
Displaced Diesel Fuel, gal 111,622 133,870 150,350
Displaced Fuel Value (2013 $) $787,336 $713,570 $657,196
Displaced Nonfuel Value (2013 $) $74,556 $42,989 $29,671
Estimated Displaced Heat Energy, kWh 808,736 834,920 849,264
Net Present Value (NPV 2013) $35,382,719 50 yr term, 2.5% discount rate
Benefit to Cost Ratio 1.32
WesleyDahl, Ambler-Shungnak Intertie Constructed, No Environmental Flows, AVEC Fuel Case, heat included
0
200
400
600
800
1000
1200
1400
1600
1800
2000
9/1 10/1 11/1 12/1 1/1 2/1 3/1 4/1 5/1 6/1 7/1 8/1Power (kW)Day of Year
Operational Chart, FY 2013 Diesel for Heat with Hydro
Hydro + Diesel for Heat, kW
Diesel for Electricity
Hydropower for Electricity
Hydropower Output
Electrical Demand
Heat + Electrical Demand
Section 7
Life-Cycle Cost Analysis
Feasibility Study and Conceptual Design Report Page 85
Cosmos Hills Hydro Feasibility
Development Scheme
Design Flow #N/A cfs
Static Head #N/A ft
Installed hydro capacity 500 kW
Annual Energy Potential 2,170,000 kWh
Design/Permitting Start 7/1/2014
Project Online Date 7/1/2018
Total Installed Cost $26,780,000
Annual O&M Cost $130,100
Net Present Cost (NPC 2013) $26,840,000 50 yr term, 2.5% discount rate
Resultant Cost Savings FY 2013 (year 0) FY 2038 (year 25) FY 2063 (year 50)
Energy Demand, kWh 2,936,651 3,766,056 4,829,710
Displaced Diesel Energy, kWh 1,292,023 1,539,025 1,742,900
Hydro Penetration 44% 41% 36%
Displaced Diesel Fuel, gal 92,353 113,899 129,571
Displaced Fuel Value (2013 $) $651,425 $607,118 $566,367
Displaced Nonfuel Value (2013 $) $72,504 $41,730 $28,903
Estimated Displaced Heat Energy, kWh 839,409 874,890 902,008
Net Present Value (NPV 2013) $30,979,769 50 yr term, 2.5% discount rate
Benefit to Cost Ratio 1.15
WesleyDahl, Ambler-Shungnak Intertie Constructed, Environmental Flows Required, AVEC Fuel Case, heat included
0
200
400
600
800
1000
1200
1400
1600
1800
2000
9/1 10/1 11/1 12/1 1/1 2/1 3/1 4/1 5/1 6/1 7/1 8/1Power (kW)Day of Year
Operational Chart, FY 2013 Diesel for Heat with Hydro
Hydro + Diesel for Heat, kW
Diesel for Electricity
Hydropower for Electricity
Hydropower Output
Electrical Demand
Heat + Electrical Demand
Section 7
Life-Cycle Cost Analysis
Feasibility Study and Conceptual Design Report Page 86
Cosmos Hills Hydro Feasibility
Exhibit 7-4: Kogoluktuk River Hydroelectric Project Summary
Development Scheme
Design Flow 170 cfs
Static Head 64 ft
Installed hydro capacity 690 kW
Annual Energy Potential 5,410,000 kWh
Design/Permitting Start 7/1/2014
Project Online Date 7/1/2019
Total Installed Cost $39,410,000
Annual O&M Cost $193,300
Net Present Cost (NPC 2013) $38,500,000 50 yr term, 2.5% discount rate
Resultant Cost Savings FY 2013 (year 0) FY 2038 (year 25) FY 2063 (year 50)
Energy Demand, kWh 2,936,651 3,766,056 4,829,710
Displaced Diesel Energy, kWh 2,804,601 3,368,950 3,921,551
Hydro Penetration 96% 89% 81%
Displaced Diesel Fuel, gal 200,472 244,702 285,300
Displaced Fuel Value (2013 $) $1,414,050 $1,304,334 $1,247,075
Displaced Nonfuel Value (2013 $) $121,524 $72,682 $77,841
Estimated Displaced Heat Energy, kWh 1,414,653 1,168,197 1,023,614
Net Present Value (NPV 2013) $63,623,701 50 yr term, 2.5% discount rate
Benefit to Cost Ratio 1.65
Kogoluktuk, Ambler-Shungnak Intertie Constructed, No Environmental Flows, AVEC Fuel Case, heat included
0
200
400
600
800
1000
1200
1400
1600
1800
2000
9/1 10/1 11/1 12/1 1/1 2/1 3/1 4/1 5/1 6/1 7/1 8/1Power (kW)Day of Year
Operational Chart, FY 2013 Diesel for Heat with Hydro
Hydro + Diesel for Heat, kW
Diesel for Electricity
Hydropower for Electricity
Hydropower Output
Electrical Demand
Heat + Electrical Demand
Section 7
Life-Cycle Cost Analysis
Feasibility Study and Conceptual Design Report Page 87
Cosmos Hills Hydro Feasibility
Development Scheme
Design Flow 170 cfs
Static Head 64 ft
Installed hydro capacity 690 kW
Annual Energy Potential 4,550,000 kWh
Design/Permitting Start 7/1/2014
Project Online Date 7/1/2019
Total Installed Cost $39,410,000
Annual O&M Cost $193,300
Net Present Cost (NPC 2013) $38,500,000 50 yr term, 2.5% discount rate
Resultant Cost Savings FY 2013 (year 0) FY 2038 (year 25) FY 2063 (year 50)
Energy Demand, kWh 2,936,651 3,766,056 4,829,710
Displaced Diesel Energy, kWh 2,232,994 2,691,254 3,145,211
Hydro Penetration 76% 71% 65%
Displaced Diesel Fuel, gal 159,614 196,260 229,808
Displaced Fuel Value (2013 $) $1,125,852 $1,046,126 $1,004,512
Displaced Nonfuel Value (2013 $) $99,864 $63,521 $73,659
Estimated Displaced Heat Energy, kWh 1,255,340 1,132,935 1,103,916
Net Present Value (NPV 2013) $52,017,833 50 yr term, 2.5% discount rate
Benefit to Cost Ratio 1.35
Kogoluktuk, Ambler-Shungnak Intertie Constructed, Environmental Flows Required, AVEC Fuel Case, heat included
0
200
400
600
800
1000
1200
1400
1600
1800
2000
9/1 10/1 11/1 12/1 1/1 2/1 3/1 4/1 5/1 6/1 7/1 8/1Power (kW)Day of Year
Operational Chart, FY 2013 Diesel for Heat with Hydro
Hydro + Diesel for Heat, kW
Diesel for Electricity
Hydropower for Electricity
Hydropower Output
Electrical Demand
Heat + Electrical Demand
Section 7
Life-Cycle Cost Analysis
Feasibility Study and Conceptual Design Report Page 88
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Section 8
Project Development Issues
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8. PROJECT DEVELOPMENT ISSUES
8.1 Land Ownership
8.1.1 Wesley Creek
The Wesley Creek project would be completely within NANA-owned lands. No Native
Allotments, private parcels, or active mining claims were identified that would need to be
impacted. The road to Bornite crosses through the project, but the ROW is controlled by
NANA.
8.1.2 Dahl Creek
The Dahl Creek project would be completely within NANA-owned lands. No Native
Allotments, private parcels, or active mining claims were identified that would need to be
impacted.
8.1.3 Kogoluktuk River
The Kogoluktuk River project would be designed to stay completely within NANA-owned
lands. The access road to the project would need to be routed to avoid crossing the State-
owned Dahl Creek runway and a Native Allotment located to the east of the runway.
No private parcels or active mining claims were identified that would need to be impacted
8.2 Permitting
Permitting requirements were not determined as part of this study.
8.3 Federal Energy Regulatory Commission (FERC) Requirements
8.3.1 Wesley Creek
The report prepared by Solstice Alaska Consulting Inc. titled, “FERC Requirements and
Field Study Recommendations,” and dated March 30, 2010 stated that a number of the
Cosmos Hills Hydroelectric projects could fall under a FERC exemption from licensing.
While not specifically listed in the report, the Wesley Creek project is very similar in type
and size to the others listed.
It is expected that the Wesley Creek project would likely be exempt from FERC licensing
for the following reasons:
• Wesley Creek is not listed as a navigable water of the U.S.
• The project would not occupy U.S. lands
• Wesley Creek is not a stream over which Congress has commercial jurisdiction
• The project would be less than 5 MW.
However, because anadromous fish (Dolly Varden) are present in Wesley Creek, it is
possible that it could be found FERC jurisdictional.
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8.3.2 Dahl Creek
The Solstice report specifically listed the Dahl Creek project as one that could fall under a
FERC exemption from licensing.
It is expected that the Dahl Creek project would likely be exempt from FERC licensing for
the following reasons:
• Dahl Creek is not listed as a navigable water of the U.S.
• The project would not occupy U.S. lands
• Dahl Creek is not a stream over which Congress has commercial jurisdiction
• The project would be less than 5 MW.
However, because anadromous fish (Dolly Varden) are present in Dahl Creek, it is possible
that it could be found FERC jurisdictional.
8.3.3 Kogoluktuk River
In 2009, AVEC secured a Preliminary Permit from the FERC for developing hydroelectric
projects on the Kogoluktuk and Shungnak Rivers. Those projects were both large dam
projects, and if developed as originally proposed, would fall under FERC’s licensing
process. However, Solstice’s report stated that smaller projects on these rivers could be
exempt. The current Kogoluktuk River project is much more similar to the ones listed than
to the original project.
A recent review of the FERC requirements and further research of the Kogoluktuk River
revealed that the Kogoluktuk River, near the powerhouse, was determined to be a Navigable
Water by the Bureau of Land Management (BLM). Just upstream of the powerhouse, the
river has been determined to be non-navigable.
Although some recreational use by whitewater rafters is reported, it is noted that flows
during the summer are well above the hydraulic capacity of the proposed project which
allows for continued utilization as a whitewater rafting reach. Signage upstream of the
diversion dam could warn potential users of the hazard.
Other factors in favor of FERC licensing exemption are the fact that the project would not
occupy U.S. lands and is less than 5 MW.
While listed as an anadromous stream, the lower cataract was observed to be a barrier to fish
passage upstream of this point. Only the tailrace outfall would be in the portion of river
where anadromous fish are present.
Because a small piece of the project is located on navigable waters of the U.S. and that
anadromous fish are present at the outfall location, it is possible that it could be required to
follow the FERC’s licensing process. However, it is expected that because the project
would have such a minimal impact to the Kogoluktuk River, it is likely that it would be
exempt.
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8.4 Fish Habitat
8.4.1 Wesley Creek
The fisheries study found Dolly Varden and slimy sculpin in Wesley Creek. The resident
fish population in the bypassed reach of the creek may result in the establishment of
minimum flows for environmental preservation. Rather than having an environmental
reservation established or determined at this point, the economic modeling performed
included scenarios with and without a presumed flow reservation equal to 12 percent of the
average annual stream flow.
A fish ladder at the intake diversion structure was not included in the conceptual design.
Providing fish passage to and from the bypassed reach of the creek would not be desired, as
this stretch of creek would be dry or have low flows. Also, the fish in this portion of the
creek are assumed to be resident, as opposed to anadromous.
8.4.2 Dahl Creek
The fisheries study found Dolly Varden in Dahl Creek. The resident fish population in the
bypassed reach of the creek may result in the establishment of minimum flows for
environmental preservation. Rather than having an environmental reservation established or
determined at this point, the economic modeling performed included scenarios with and
without a presumed flow reservation equal to 12 percent of the average annual stream flow.
A fish ladder at the intake diversion structure was not included in the conceptual design.
Providing fish passage to and from the bypassed reach of the creek would not be desired, as
this stretch of creek would be dry or have low flows. Also, the fish in this portion of the
creek are assumed to be resident, as opposed to anadromous.
8.4.3 Kogoluktuk River
The fisheries study found several fish species in the Kogoluktuk River, including Chum
Salmon, Dolly Varden, slimy sculpin, arctic grayling, northern pike, and round whitefish.
The lower cataract section of Kogoluktuk River, just above the powerhouse site, appears to
be a velocity barrier for anadromous fish, as chum salmon were found below the
powerhouse site but not above. The resident fish population in the bypassed reach of the
river may result in the establishment of minimum flows for environmental preservation.
Rather than having an environmental reservation established or determined at this point, the
economic modeling performed included scenarios with and without a presumed flow
reservation equal to 8 percent of the average annual stream flow.
A fish ladder at the intake diversion structure was not included in the conceptual design.
Providing fish passage to and from the bypassed reach of the river would not be necessary,
as the lower cataract already limits fish passage.
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8.5 Constructability
8.5.1 Wesley Creek
The Wesley Creek project will be a fairly straight-forward construction project. Access to
much of the project site already exists. A considerable portion is along the existing Bornite
Mine Road. Only a short access road will need to be constructed to the powerhouse site.
Difficulties may be encountered during excavations, particularly in the upper reaches of the
project. Large boulders are present on the surface near the intake and down to the bridge
crossing Bornite Mine Road. Trenching and structure excavations may be slowed by these
boulders.
8.5.2 Dahl Creek
The Dahl Creek project will also be a fairly straight-forward construction project, but may
be a bit more difficult than the Wesley Creek project. Primitive access to much of the
project site already exists. Old mining trails follow the creek to the intake location.
Difficulties will be constructing the trench and access road through some of the narrow steep
valley sections. The penstock also will cross the creek in at least two locations and will
require trenching across the creek.
8.5.3 Kogoluktuk River
The Kogoluktuk River project will be the most difficult of the three projects. No access to
the project area currently exists. A six-mile access road will need to be constructed before
any of the other portions of the project can begin.
The penstock alignment will follow the river along very steep terrain. An approximately 30-
foot wide bench will need to be blasted out of the side of the rock slopes to install the
penstock on. This bench will also be used to access the intake location. Once the bench is
constructed, the penstock construction will be straight forward.
Intake construction will also be more difficult than the other two locations, as the water flow
is significantly greater at the Kogoluktuk River and cannot be easily redirected.
8.6 Winter Operations
All of the projects are generally expected to be able to operate down to the minimum
hydraulic capacity of the turbines during the winter months, so long as water can flow
through the intake and out the tailrace. The shoulder seasons of winter will typically be the
most difficult in terms of winter operations. In early winter icing in river presents problems
and in the spring broken and moving ice can dam up flows.
Occasional outages can be expected in the early winter from icing related events (frazil ice)
that can prevent water from entering the intake. These events, while minimized, could still
occur, precipitated by the onset of cold temperatures. They are likely at their worst when
the accumulated heating degree days are unusually high before the formation of an
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insulating cover of ice and snow over the stream. Frazil ice forms when water in streams
falls below freezing and tiny ice crystals begin to form within the flowing water. The ice
crystals adhere to the stream bottom and continue to grow into larger masses that can
obstruct flow. Rivers and streams in this situation are essentially freezing from the “bottom-
up.” Tailrace discharge potentially can be disrupted by frazil ice events as well.
The investigation by GWS included remote camera installations that monitored ice buildup
during the winter. GWS notes that the station at Wesley Creek and the Kogoluktuk River
showed open water leads through most of the winter. Stream reaches that exhibit greater
ground water inflow will likely have fewer problems with icing. In areas where water is
being lost to groundwater flow, aufeis and glacial events can be expected to be worse.
In order to improve successful winter operations, it is important to identify locations where
open leads are present representing good groundwater inflow support (both Wesley and the
Kogoluktuk intakes are located near likely high groundwater inflow locations), promote
early ice cover formation for insulation (accomplished by having slack pools of water such
as created by the diversion structures), and maintaining flowing conditions in confined
channels. These considerations should be evaluated for both the intake and tailrace
locations.
Another area of concern during the winter months is the penstocks. Water conveyance in
above-ground pipelines in cold climates is fairly common throughout rural Alaska, although
there are operational issues. Generally, these systems transport drinking water that has been
stored at temperatures around 40 degrees Fahrenheit. In the case of the projects being
considered for this project, the intake water temperatures will be closer to the freezing point.
However, the typical water main is an 8-inch diameter pipe. The projects being considered
will utilize 24-inch and 72-inch diameter pipes. The mass of water in these pipes will be 9
and 81 times the mass of water than in the smaller diameter water mains, requiring 9 or 81
times the energy loss to freeze the pipes.
The engineering design must be thorough in regards to the winter operating temperatures. It
is critical that the design ensure that continual flow is maintained. Design strategies that
should be investigated include:
• Perform a detailed thermal analysis of the entire system
• Design the pipes to flow full, so that water in the pipe will not be directly exposed to
air temperatures
• Place the intake below the water surface
• Discharge the tailrace below the receiving water surface
• Provide a simple bypass around the turbine to maintain a constant flow during a
shutdown
• Use insulated pipe
• Consider buried pipe
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Section 9
Recommendations and Conclusions
Feasibility Study and Conceptual Design Report Page 95
Cosmos Hills Hydro Feasibility
9. RECOMMENDATIONS AND CONCLUSIONS
9.1 Feasible Projects
The results of this feasibility study indicate that any of the individual development schemes
can offer potential for savings given the right circumstances.
9.1.1 Land Ownership Issues
There are no significant ownership or land use issues with the potential hydro projects.
Each would be on land owned by NANA Regional Corporation. All of the access routes are
on NANA-owned land. None affect any private parcels or mining claims, though the
potential road to the Kogoluktuk would need to be routed to avoid the Dahl Creek runway
and a Native Allotment.
9.1.2 Permitting/FERC/Environmental Issues
None of the projects appear to have serious permitting/FERC/environmental issues. All
projects would be obviously or likely exempt from the FERC process. None of the projects
have obvious permitting pitfalls, except that the extent of required environmental flows
needs to be determined. These flows have a significant effect on the projects’ benefits.
Determination of required environmental flows typically occurs during permitting and final
design.
9.1.3 Constructability
None of the projects have unusual constructability issues. The Wesley and Dahl projects
should have a straightforward construction process. Access to much of the Wesley project
already exists. Primitive access exists to the Dahl site. The Kogoluktuk would be a little
more difficult, because a six-mile access road will need to be constructed before the project
can begin construction. In addition, the penstock route will require blasting in steep terrain.
The increased cost for this construction is included in the Kogoluktuk’s construction
estimate. Otherwise, this project also does not present unusual constructability issues.
9.1.4 Sensitivity to Hydrologic Changes
The economic analysis and power generation estimates for the three projects are based on
the median streamflow. Because the Wesley and Dahl projects use most of the flow in the
respective creeks, these two projects are more susceptible to hydrologic fluctuations. In dry
years, they would produce less power. In some wet years, possibly more.
The Kogoluktuk project is much less sensitive to changes in hydrology. Because this project
uses a small amount of a large flow, it is not very sensitive to dry years and has a hydraulic
advantage in reducing the amount of debris and sediment diverted into the intake. The river
would have to have extremely low flow before it greatly affected the Kogoluktuk output. In
addition, wet years would have little effect on the electricity output. The Kogoluktuk’s
power output and economic conclusions are therefore somewhat more reliable than the other
two projects.
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Recommendations and Conclusions
Feasibility Study and Conceptual Design Report Page 96
Cosmos Hills Hydro Feasibility
9.1.5 Economic Feasibility Excluding Electric Heat
As explained in Section 7.3.2, the economic analysis completed for this project uses
conservative economic assumptions: it uses conservative load growth, excludes likely
mineral exploration loads, and uses two ISER fuel price scenarios which underestimate air
deliveries and therefore underestimate likely fuel prices. With these assumptions and
electric heat excluded, a hydro project is the best alternative for 10 of the 12 scenarios.
If the Ambler Intertie is not constructed, the Wesley or Dahl project has the highest
Benefit/Cost ratio (except for the ISER Medium fuel cases). However, the Kogoluktuk has
the lowest cost of power for two of the non-intertie scenarios. If, as expected, the Ambler
Intertie is constructed, the Kogoluktuk River project has the lowest Net Cost of Power in
five of the six scenarios (the ISER Medium fuel case producing one diesel-best result).
9.1.6 Economic Feasibility Including Electric Heat
Including the value of electric heat from electricity that is surplus to the villages’ electric
demand changes the economic conclusions. If the value of electric heat is included, the
Kogoluktuk River is the preferred hydro project for all scenarios (though one Medium ISER
Fuel case has a Benefit/Cost ratio of less than 1.00).
9.2 Recommended Project: Kogoluktuk River Hydroelectric Project
The smaller projects, Wesley Creek, Dahl Creek, and the combination of those two projects,
present a different situation than the Kogoluktuk River Project. For much of the year, the
villages will use essentially all of the smaller projects’ output on the day they open. These
projects decrease the average cost of electricity, but do nothing for the marginal electricity
cost. Significant village growth would still require new diesel-generated electricity.
Because PCE payments would decrease with the lower average cost, the project’s benefit
would be absorbed by lower PCE payments and result in little benefit to many individual
residential consumers. Those residents who use more than 500 kWh/month, the school
district, and the very few commercial facilities would all benefit.
The Dahl and Wesley Creek projects would likely stabilize electricity cost – the price would
not go up with oil price increases, but much of the benefit is absorbed by the state in lower
PCE payments. If the smaller projects are built, many residential consumers would be in a
very similar situation to their current condition with respect to the effective residential
electricity price (after PCE), and the village would not have the ability to attract new
businesses with low energy prices.
The Kogoluktuk River Hydro Project presents a different situation. It is economically viable
using the same assumptions as the smaller projects: i.e., it is not a “build-it-and-they-will-
come” project. But the project transforms economic opportunity for the villages. First, the
ability to use surplus electricity for heat provides the villages and possibly even residential
consumers with significant and direct benefits. Assuming use of surplus electricity for heat,
it is the preferred project in all scenarios that include the Ambler Intertie. Second, the
project has excess electric capacity. This means that the marginal cost of electricity is low.
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It allows the villages to use the potential for low electric prices for commercial and
industrial purposes. The other projects do not provide the same opportunity.
There are other reasons that the Kogoluktuk River Project is preferred. These include
information that is not captured in the economic analysis. The paragraphs below summarize
reasons to prefer the Kogoluktuk project over its alternatives.
• Direct Benefit to Villages and Residents through Electric Heat. A decrease in
electricity rate is accompanied by a decrease in PCE payments. As a result, many
residents do not see significantly lower utility bills from projects that focus solely on
electricity. The Kogoluktuk project has the ability to generate significant direct and
immediate benefits to the villages and residents from using surplus electricity for
heat.
• Support by Villages and Regional Groups. NANA and AVEC have indicated that
they support going forward with the Kogoluktuk project over the other alternatives.
NovaCopper, Inc. is expected to concur. In addition, because of the direct benefits to
villages, the Kogoluktuk project is expected to get more support from village
residents than the alternative projects. This support has a number of benefits.
First, the project team expects that this project will be funded by direct legislative
appropriation. They expect it to be part of Alaska’s capital budget because it appears
to be too large to be funded from the Renewable Energy Fund. Gathering village
and regional groups’ support is important for a project’s consideration by the
legislature.
Second, support by these groups has some role in stabilizing or lower project costs.
NANA and NovaCopper, Inc. have provided in-kind support to preliminary
investigation of the projects. The potential for in-kind support helps the project with
costs and schedule. The potential for support increases if the groups favor the
project being built. This potential support is important but is not captured by the
economic analysis.
• Economic Opportunity for the Villages. Because the Kogoluktuk project can
produce electricity beyond the villages’ present electric needs, it provides
opportunity for the future. No one knows whether these villages can develop an
economic base for themselves. However, the Kogoluktuk project gives them that
opportunity, and the other projects do not. This opportunity is important for the
villages and is not captured by the economic analysis.
• Improves the Potential for Mineral Development. This point is related to the
previous point. Mineral development has the potential to provide a missing
economic base to the region. Because the Kogoluktuk project, but not the alternative
projects, has excess electric generation, it could lower the exploration costs in the
region. This has potential to benefit the region in employment and expedited
exploration.
• Project is Improved with Less Conservative Load Assumptions. The economic
analysis used 1% load growth. Elsewhere, this report explains why that growth
projection is conservative. If actual loads grow at a faster rate than forecast, the
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economic returns (i.e., the Benefit/Cost Ratio) increase more for the Kogoluktuk
project than for the alternatives.
• Less Sensitivity to Hydrologic Changes. As explained earlier in this section, the
electric output of the Kogoluktuk project is much less sensitive to dry years than are
the other projects. The Kogoluktuk’s power output and economic conclusions are
therefore more reliable than the other projects. The benefits of the Kogoluktuk
remain stable in dry years when the alternative projects’ benefits are smaller.
• Kogoluktuk Project is Expandable. The Kogoluktuk River has much greater flow
than Dahl or Wesley Creeks. The Kogoluktuk Project uses only a portion of the
available flow and could be expanded in capacity if additional power is needed.
Additionally, the intake site has the potential to accommodate a higher dam and
would create a significant storage reservoir. In the event that a road comes to the
region, a mine is developed, or another large economic opportunity occurs, it may be
possible to construct a dam on the river and generate significantly more power. Of
course, economic development that would allow such an expansion is entirely
speculative and is appropriately excluded from the economic analysis of this report.
But it is important, nonetheless.
The primary downside to the Kogoluktuk Project is that it has larger construction cost than
the Wesley, Dahl, or the combined Wesley + Dahl projects. However, the Net Present Cost
of Power analysis shows that the Kogoluktuk provides the greatest benefit for more
scenarios than other projects (See Table 7-6). The Benefit Cost Ratios (Table 7-8) show that
it is a favored project for three of the six scenarios involving the Ambler Intertie. (Dahl is
favored in two and continued diesel generation in one.) And when electric heat is included
in the analysis, the Kogoluktuk Project is preferred in most scenarios overall, and in all
scenarios that assume the Ambler Intertie. Therefore, the project is economically preferable
without including speculative demands.
9.3 Next Steps
The next steps for this project are to advance the concept design to the 65% complete stage
and complete the environmental requirements. To get there, the following list of action
items are identified.
Obtain Funding
• Look for additional funding to allow work to continue. This will include:
• Prepare a plan of work to be completed.
• Meet with potential partners, such as NANA, Northwest Arctic Borough (NAB),
State of Alaska, Tribal governments, etc., and elicit their support, participation,
and funding.
Public Involvement
• Once the project starts back up, meet with the local communities to update them on
the status of the project and to gather their input.
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• After the 35% design is complete, meet with the local communities to update them
on the status of the project and to gather their input.
• After the 65% design is complete, meet with the local communities to update them
on the status of the project and to gather their input.
Environmental / Permits
• Discuss fish habitat issues with the Alaska Department of Fish and Game (ADF&G)
to ascertain their concerns, especially environmental flow requirements.
• Perform any fish habitat field studies required by ADF&G during summer.
• Meet with the other agencies to identify any environmental and/or permitting
requirements they may have.
• Prepare and submit a jurisdictional determination application with the Federal
Energy Regulatory Commission (FERC) to determine if the project can be exempted
from the FERC licensing process.
• File for water rights with the Alaska Department of Natural Resources (ADNR).
• Once the 65% design is complete, apply for the identified permits.
Survey / Right-of-Way
• Obtain Lidar data for the area between the existing road system and transmission
lines and the lower extents of the existing Kogoluktuk River data. This would be
best accomplished in the fall, when foliage and leaf cover is at a minimum.
• Perform a detailed field survey of the river at the intake and tailrace locations. This
will include the topographic features of the river bed below the water surface and the
terrain in the immediate area of the structures. This information is needed to perform
the detailed hydraulic analyses at the intake and tailrace outfall.
• Prior to beginning the 35% design, meet with land owners regarding easement and
property acquisitions.
• Once the locations and alignments of the various components are determined (35%
complete), meet with land owners to continue the acquisition process.
Hydrology / Hydraulics
• Relocate and/or maintain the Lower Kogoluktuk River discharge station. Locate the
webcam to focus on the intake location. Also, add another station, with a webcam, at
the tailrace location.
• Perform a sediment transport investigation. This information is needed to analyze
the erosion and scour potentials, and the anticipated seepage at the diversion and
intake structure. It will then be used to design the appropriate control measures.
• Perform the hydraulic analyses, using the information obtained in the field studies
and surveys. This information will be used to design the intake and outfall
structures, as well as sizing the penstock and turbine.
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Geotechnical
• Perform geotechnical investigations at the intake location, along the penstock
alignment, and at the powerhouse location. These will be critical in finalizing the
concept designs.
• Perform geotechnical investigations along the access road and power transmission
alignments.
• Determine potential material sources.
35% Design
• Perform a detailed thermal analysis of the entire system, including the intake,
penstock, tailrace, and outfall.
• Incorporate the new studies and surveys (fish habitat, topographical and right-of-way
surveys, hydrology, hydraulic, sediment transport, erosion/scour, and geotechnical)
into the design.
• Prepare 35% complete design drawings. This work will consist of:
• Detailed hydraulic design of the diversion and intake structures, including
erosion and scour protection, seepage control, “self-cleaning” features, icing
avoidance measures, etc.
• Intake and diversion site plan and concrete details.
• Penstock alignment analysis to minimize rock excavation and construction costs,
resulting in detailed plan and profile drawings.
• Penstock pipeline details, including support, anchoring, pipe size and material,
joints, valves, insulation, etc.
• Powerhouse site plan, foundation design, building and equipment layout, and
details.
• Detailed hydraulic design of the tailrace, including erosion and scour protection,
icing avoidance measures, etc.
• Tailrace site plan and details.
• Access road alignment plan and profile drawings, typical sections, culvert details,
etc.
• Power transmission design, including alignment, pole details, etc.
65% Design
• Receive and incorporate review comments and complete the design to the 65% level,
including plans, specifications, and construction cost estimate.
References
Feasibility Study and Conceptual Design Report Page 101
Cosmos Hills Hydro Feasibility
10. REFERENCES
AVEC Kobuk, Alaska Village Electric Cooperative CEO Message AK-105, "Kobuk Joins
the AVEC Family,” July 2012.
NWAB Kobuk Comp Plan, Northwest Arctic Borough,
http://www.nwabor.org/forms/Kobuk%20Comp%20Plan.pdf.
US Department of Commerce, NOAA, NCDC, Bettles Airport, AK US Monthly Normals.
AEA PCE, Alaska Energy Authority, Power Cost Equalization program,
http://www.akenergyauthority.org/programspce.html.
MOA, Municipality of Anchorage,
http://www.muni.org/Departments/works/project_management/Pages/FloodHazard.aspx,
July 2013.
G-W Scientific; Michael R. Lilly, David Brailey, Kristie Hilton, Ron Paetzold, and Austin
McHugh; Cosmos Hills Hydrologic Network Installation and Operation, August 2010-
December 2011; May, 2012.
AVEC 2012 PCE Annual Report, Regulatory Commission of Alaska,
http://rca.alaska.gov/RCAWeb/ViewFile.aspx?id=9BD1B3E1-F759-4DCD-A76A-
512DA43F81F0.
ISER Fuel Price Projections, Alaska Fuel Price Projections 2013-2035, report
http://www.iser.uaa.alaska.edu/Publications/2013_06-
Fuel_price_projection_2013final_06302013.pdf and spreadsheet
http://www.iser.uaa.alaska.edu/Publications/2013_06-Fuel_price_projection_2013-
2035_Final_06302013.xlsx
Hatch 2012, Hatch, Daniel Hertrich, Cosmos Hills Hydroelectric Project Reconnaissance
Trip Report, 12/3/2012.
Hydrology Resource: http://cosmos.gwscientific.com/Main/HomePage, password
“hydropower,” hydrology data files containing data collected from each of the resources
considered in this report for the 2010/2011 water year. Files are located on page
http://cosmos.gwscientific.com/Main/2011SQ. Files used include the following excel files:
• Upper_Wesley_Creek_Corrected_Stage_Mean_Daily_Flow.xlsx
• Upper_Cosmos_Creek_Corrected_Stage_Mean_Daily_Flow.xlsx
• Upper_Kogoluktuk_River_Corrected_Stage_Mean_Daily_Flow.xlsx
• Upper_Dahl_Creek_Corrected_Stage_Mean_Daily_Flow.xlsx
References
Feasibility Study and Conceptual Design Report Page 102
Cosmos Hills Hydro Feasibility
This page left intentionally blank
Appendices
Wesley Creek Conceptual Design: A
Dahl Creek Conceptual Design: B
Kogoluktuk River Conceptual Design: C
Concept-Level Construction Cost Estimate: D
Appendix A
Wesley Creek Conceptual Design
Overall Site Plan: W-1
Penstock – Plan & Profile: W-2
Penstock – Plan & Profile: W-3
Penstock – Plan & Profile: W-4
Tailrace – Plan & Profile: W-5
Intake/Diversion Structure – Plan: W-6
Intake/Diversion Structure – Sections: W-7
Powerhouse General Arrangement – Plan: W-8
Powerhouse General Arrangement – Section: W-9
1 2
A
B
23'-0"23'-2"1'-0"1'-0"1'-5"1'-5"10'-0" INSULATED
ROLL UP OH DOOR
WITH EXT INSULATION
SWITCHGEAR
GENERATOR
TURBINE
SMOOTH LINED
HDPE 36" CULVERT
AIR RELEASE VENT
INSULATION
CONCRETE
PIPELINE
THRUST BLOCK
24" BFV
W-9
A
W-9
A
PLAN
SCALE: 3/16" = 1'-0"
TRANSFORMER
300 West 31st AvenueAnchorage, AK 99503907-339-6500 Fax 907-339-5327www.whpacific.comFIGURE NO.:
CHECKED BY:
DRAWN BY:
JOB NO.:
DATE:Cosmos Hills Hydro Feasibility (AEA Grant No. 2195413)Alaska Village Electric Cooperative5558
Aug. 2013
FR
DH
W - 8WESLEY CREEK - CONCEPTUAL DESIGNPOWERHOUSE GENERAL ARRANGEMENT - PLANPARKING AND BUILDING PAD AREA
(30' OUTSIDE BUILDING LIMITS)
29'-0"1'-0"1'-0"8'-0"11'-0"1'-0"5'-6"
12'-3"
1'-6"
2'-6"1'-1112"8"6"EXISTING
GROUND
PREFABRICATED,
THERMALLY ISOLATED
BUILDING STRUCTURE
& EXTERIOR INSULATION
6" RIGID
INSULATION
3/16" = 1'-0"
SECTION
W-8
A
24" HDPE
PIPELINE
AIR RELEASE VENT
CHECK
VALVE
SCREEN
8'-0"
4" XPS RIGID
FOAM INSULATION
TAILRACE
2" PIPELINE
DRAIN
2" BALL
VALVE
CULVERT, ENCASE
BEVELED OUTLET
IN CONCRETE
CONCRETE OUTLET
SUPPORT F.G.
VARYING
WATER LEVELS
CREEK BED/BANK
WESLEY CREEK
TAILRACE OUTLET 300 West 31st AvenueAnchorage, AK 99503907-339-6500 Fax 907-339-5327www.whpacific.comFIGURE NO.:
CHECKED BY:
DRAWN BY:
JOB NO.:
DATE:Cosmos Hills Hydro Feasibility (AEA Grant No. 2195413)Alaska Village Electric Cooperative5558
Aug. 2013
FR
DH
W - 9WESLEY CREEK - CONCEPTUAL DESIGNPOWERHOUSE GENERAL ARRANGEMENT - SECTIONSMOOTH LINED
HDPE 36" CULVERT
Appendix B
Dahl Creek Conceptual Design
Overall Site Plan: D-1
Penstock – Plan & Profile: D-2
Penstock – Plan & Profile: D-3
Penstock – Plan & Profile: D-4
Penstock – Plan & Profile: D-5
Access Road: D-6
Intake/Diversion Area Plan: D-7
Intake/Diversion Structure - Plan: D-8
Intake/Diversion Structure – Sections: D-9
Powerhouse General Arrangement – Plan: D-10
Powerhouse General Arrangement – Section: D-11
1 2
A
B
23'-0"23'-2"1'-0"1'-0"1'-5"1'-5"10'-0" INSULATED
ROLL UP OH DOOR
WITH EXT INSULATION
SWITCHGEAR
GENERATOR
TURBINE
SMOOTH LINED
HDPE 36" CULVERT
AIR RELEASE VENT
INSULATION
CONCRETE
PIPELINE
THRUST BLOCK
24" BFV
D - 9
A
D - 9
A
PLAN
SCALE: 3/16" = 1'-0"
TRANSFORMER
300 West 31st AvenueAnchorage, AK 99503907-339-6500 Fax 907-339-5327www.whpacific.comFIGURE NO.:
CHECKED BY:
DRAWN BY:
JOB NO.:
DATE:Cosmos Hills Hydro Feasibility (AEA Grant No. 2195413)Alaska Village Electric Cooperative5558
Aug. 2013
FR
DH
D - 8DAHL CREEK - CONCEPTUAL DESIGNPOWERHOUSE GENERAL ARRANGEMENT - PLANPARKING AND BUILDING PAD AREA
(30' OUTSIDE BUILDING LIMITS)
29'-0"1'-0"1'-0"8'-0"11'-0"1'-0"5'-6"
12'-3"
1'-6"
2'-6"1'-1112"8"6"EXISTING
GROUND
PREFABRICATED,
THERMALLY ISOLATED
BUILDING STRUCTURE
& EXTERIOR INSULATION
6" RIGID
INSULATION
3/16" = 1'-0"
SECTION
D - 8
A
24" HDPE
PIPELINE
AIR RELEASE VENT
CHECK
VALVE
SCREEN
8'-0"
4" XPS RIGID
FOAM INSULATION
TAILRACE
2" PIPELINE
DRAIN
2" BALL
VALVE
CULVERT, ENCASE
BEVELED OUTLET
IN CONCRETE
CONCRETE OUTLET
SUPPORT F.G.
VARYING
WATER LEVELS
CREEK BED/BANK
DAHL CREEK
TAILRACE OUTLET
SMOOTH LINED
HDPE 36" CULVERT 300 West 31st AvenueAnchorage, AK 99503907-339-6500 Fax 907-339-5327www.whpacific.comFIGURE NO.:
CHECKED BY:
DRAWN BY:
JOB NO.:
DATE:Cosmos Hills Hydro Feasibility (AEA Grant No. 2195413)Alaska Village Electric Cooperative5558
Aug. 2013
FR
DH
D - 9DAHL CREEK - CONCEPTUAL DESIGNPOWERHOUSE GENERAL ARRANGEMENT - SECTION
Appendix C
Kogoluktuk River Concept Design
Overall Site Plan: K-1
Penstock – Plan & Profile: K-2
Penstock – Plan & Profile: K-3
Access Road: K-4
Access Road: K-5
Intake/Diversion Area Plan: K-6
Intake/Diversion Structure - Plan: K-7
Intake/Diversion Structure – Sections: K-8
Intake/Diversion Structure – Sections: K-9
Powerhouse General Arrangement – Plan: K-10
Powerhouse General Arrangement – Section: K-11
13'-7"13'-7"
PLAN
SCALE: 1/8" = 1'-0"24'-0"ACCESS HATCH &
LADDER
10'-0" INSULATED
ROLL UP OH DOOR
5' WIDE, 4" INSULATED
WALL PANEL & HINGED WITH
LATCH COVERING OH DOOR
MAN DOOR
4'Ø PIPE
4' BFV
GENERATOR
12" CONC.
WALL BELOW
CRANE RAIL
CRANE RAIL
CRANE BEAM
F L O W
3
K-11
A
K-11
A
21
A
B
SWITCHGEAR
TURBINE
LIFT HATCH
6" EXT SIDING &
INSULATED WALL PANEL
8" METAL BLDG
FRAMING
TURBINE BLOCK
DUAL 6'Ø CULVERT
ACCESS HATCHES
CONCRETE
THRUST BLOCK
INSULATION
STOPLOG WALL 300 West 31st AvenueAnchorage, AK 99503907-339-6500 Fax 907-339-5327www.whpacific.comFIGURE NO.:
CHECKED BY:
DRAWN BY:
JOB NO.:
DATE:Cosmos Hills Hydro Feasibility (AEA Grant No. 2195413)Alaska Village Electric Cooperative5558
Aug. 2013
FR
DH
K - 10KOGOLUKTUK RIVER - CONCEPTUAL DESIGNPOWERHOUSE GENERAL ARRANGEMENT - PLAN
5'-0"15'-7"9'-2"15'-0"14'-6"10'-7"8'-512"15'-7"30'-0"
ORIGINAL
GROUND SURFACE
CANYON KAPLAN
TURBINE
SYNCHRONOUS
GENERATOR
3/480/60
TURBINE INLET
TAILRACE
DISCHARGE
F L O W
TWL EL.170'
EL. 180'
6"Ø HDPE PIPE
WITH INSULATION
INSULATION
6"x 4"
REDUCER
1/8" = 1'-0"
SECTION
K-10
A
BUILDING FRAME/
CRANE STRUCTURE
BUILDING EXTERIOR
FRAMING
6" INSULATED
WALL PANEL
4" INSULATION
CONCRETE THRUST
BLOCK AND FOUNDATION
4"Ø TURBINE
INLET VALVE
(BUTTERFLY)
EL. 160'DUAL 6'Ø CULVERT
4" BV AND
DRAIN PIPE
EL. 205'
STOPLOG WALL 300 West 31st AvenueAnchorage, AK 99503907-339-6500 Fax 907-339-5327www.whpacific.comFIGURE NO.:
CHECKED BY:
DRAWN BY:
JOB NO.:
DATE:Cosmos Hills Hydro Feasibility (AEA Grant No. 2195413)Alaska Village Electric Cooperative5558
Aug. 2013
FR
DH
K - 11KOGOLUKTUK RIVER - CONCEPTUAL DESIGNPOWERHOUSE GENERAL ARRANGEMENT - SECTION
Appendix D
Conceptual-Level Construction
Cost Estimates
WESLEY CREEK
ENGINEER'S CONCEPTUAL-LEVEL CONSTRUCTION COST ESTIMATE
ITEM DESCRIPTION UNIT
ESTIMATED
QUANTITY
UNIT
PRICE AMOUNT
MOBILIZATION $1,900,000.00
MOBILIZATION / DEMOBILIZATION LUMP SUM ALL REQUIRED $1,250,000 $1,250,000
WORKER MEALS AND LODGING (REMOTE CAMP)MAN-DAY 1,300 $500 $650,000
DIVERSION / INTAKE STRUCTURES $1,230,000.00
DEWATERING AND RIVER CONTROL LUMP SUM ALL REQUIRED $250,000 $250,000
ROCK ANCHORS LUMP SUM ALL REQUIRED $75,000 $75,000
CONCRETE STRUCTURES CUBIC YARD 250 $3,000 $750,000
SCREENS LUMP SUM ALL REQUIRED $50,000 $50,000
STOP LOGS LUMP SUM ALL REQUIRED $75,000 $75,000
GATE VALVES EACH 2 $15,000 $30,000
PENSTOCK $2,298,600.00
24" HDPE SDR 11 PIPE LINEAR FOOT 7,800 $235 $1,833,000
TRENCH INSULATION (4" BOARDSTOCK)SQUARE FOOT 62,400 $6.50 $405,600
GATE VALVES EACH 4 $15,000 $60,000
TAILRACE $331,500.00
36" HDPE SDR 11 PIPE LINEAR FOOT 750 $390 $292,500
TRENCH INSULATION (4" BOARDSTOCK)SQUARE FOOT 6,000 $6.50 $39,000
POWER HOUSE $1,575,000.00
FOUNDATION CUBIC YARD 200 $3,000 $600,000
BUILDING LUMP SUM ALL REQUIRED $250,000 $250,000
EQUIPMENT LUMP SUM ALL REQUIRED $725,000 $725,000
ACCESS ROAD $329,600.00
CLEARING AND GRUBBING ACRE 4.9 $20,000 $98,000
EXCAVATION CUBIC YARD 1,500 $15 $22,500
GEOTEXTILE (SEPARATION)SQUARE YARD 8,700 $3 $26,100
BORROW CUBIC YARD 3,800 $35 $133,000
24-INCH CULVERT LINEAR FOOT 200 $250 $50,000
ELECTRICAL TRANSMISSION $926,000.00
TRANSMISSION LINE LINEAR FOOT 10,600 $85 $901,000
TRANSFORMER EACH 1 $25,000 $25,000
MISCELLANEOUS $225,000.00
EROSION AND SEDIMENT CONTROL LUMP SUM ALL REQUIRED $100,000 $100,000
CONSTRUCTION SURVEYING LUMP SUM ALL REQUIRED $125,000 $125,000
$0
CONSTRUCTION SUBTOTAL: (SUM OF ABOVE) $8,815,700.00
BONDING AND INSURANCE: (5% OF CONSTRUCTION SUBTOTAL)5% $440,785
CONSTRUCTION ENGINEERING AND ADMINISTRATION: (10% OF ABOVE TWO ITEMS) 10% $925,649
CONTINGENCY: (25% OF ABOVE THREE ITEMS) 25% $2,545,533
TOTAL CONSTRUCTION PROJECT COSTS:$12,727,700.00
PRECONSTRUCTION COSTS: 7% of Total Construction Costs 7.0%$890,939
(SURVEY, GEOTECHNICAL, ENVIRONMENTAL, DESIGN, PERMITTING)
TOTAL PROJECT DEVELOPMENT COSTS:$13,618,639
DAHL CREEK
ENGINEER'S CONCEPTUAL-LEVEL CONSTRUCTION COST ESTIMATE
ITEM DESCRIPTION UNIT
ESTIMATED
QUANTITY
UNIT
PRICE AMOUNT
MOBILIZATION $1,960,000.00
MOBILIZATION / DEMOBILIZATION LUMP SUM ALL REQUIRED $1,250,000 $1,250,000
WORKER MEALS AND LODGING (REMOTE CAMP)MAN-DAY 1,420 $500 $710,000
DIVERSION / INTAKE STRUCTURES $1,480,000.00
DEWATERING AND RIVER CONTROL LUMP SUM ALL REQUIRED $250,000 $250,000
ROCK ANCHORS LUMP SUM ALL REQUIRED $100,000 $100,000
CONCRETE STRUCTURES CUBIC YARD 325 $3,000 $975,000
SCREENS LUMP SUM ALL REQUIRED $50,000 $50,000
STOP LOGS LUMP SUM ALL REQUIRED $75,000 $75,000
GATE VALVES EACH 2 $15,000 $30,000
PENSTOCK $2,658,000.00
24" HDPE SDR 11 PIPE LINEAR FOOT 9,000 $235 $2,115,000
TRENCH INSULATION (4" BOARDSTOCK)SQUARE FOOT 72,000 $6.50 $468,000
GATE VALVES EACH 5 $15,000 $75,000
TAILRACE $44,200.00
36" HDPE SDR 11 PIPE LINEAR FOOT 100 $390 $39,000
TRENCH INSULATION (4" BOARDSTOCK)SQUARE FOOT 800 $6.50 $5,200
POWER HOUSE $1,675,000.00
FOUNDATION CUBIC YARD 200 $3,000 $600,000
BUILDING LUMP SUM ALL REQUIRED $250,000 $250,000
EQUIPMENT LUMP SUM ALL REQUIRED $825,000 $825,000
ACCESS ROAD $901,600.00
CLEARING AND GRUBBING ACRE 8.0 $20,000 $160,000
EXCAVATION CUBIC YARD 7,400 $15 $111,000
GEOTEXTILE (SEPARATION)SQUARE YARD 29,200 $3 $87,600
BORROW CUBIC YARD 13,400 $35 $469,000
12-INCH CULVERT LINEAR FOOT 360 $150 $54,000
24-INCH CULVERT LINEAR FOOT 80 $250 $20,000
ELECTRICAL TRANSMISSION $926,000.00
TRANSMISSION LINE LINEAR FOOT 10,600 $85 $901,000
TRANSFORMER EACH 1 $25,000 $25,000
MISCELLANEOUS $225,000.00
EROSION AND SEDIMENT CONTROL LUMP SUM ALL REQUIRED $100,000 $100,000
CONSTRUCTION SURVEYING LUMP SUM ALL REQUIRED $125,000 $125,000
$0
CONSTRUCTION SUBTOTAL: (SUM OF ABOVE) $9,869,800.00
BONDING AND INSURANCE: (5% OF CONSTRUCTION SUBTOTAL)5% $493,490
CONSTRUCTION ENGINEERING AND ADMINISTRATION: (10% OF ABOVE TWO ITEMS) 10% $1,036,329
CONTINGENCY: (25% OF ABOVE THREE ITEMS) 25% $2,849,905
TOTAL CONSTRUCTION PROJECT COSTS:$14,249,500.00
PRECONSTRUCTION COSTS: 7% of Total Construction Costs 7.0%$997,465
(SURVEY, GEOTECHNICAL, ENVIRONMENTAL, DESIGN, PERMITTING)
TOTAL PROJECT DEVELOPMENT COSTS:$15,246,965
WESLEY CREEK AND DAHL CREEK COMBINED
ENGINEER'S CONCEPTUAL-LEVEL CONSTRUCTION COST ESTIMATE
ITEM DESCRIPTION UNIT
ESTIMATED
QUANTITY
UNIT
PRICE AMOUNT
MOBILIZATION $2,685,000.00
MOBILIZATION / DEMOBILIZATION LUMP SUM ALL REQUIRED $1,600,000 $1,600,000
WORKER MEALS AND LODGING (REMOTE CAMP)MAN-DAY 2,170 $500 $1,085,000
DIVERSION / INTAKE STRUCTURES $2,710,000.00
DEWATERING AND RIVER CONTROL LUMP SUM ALL REQUIRED $500,000 $500,000
ROCK ANCHORS LUMP SUM ALL REQUIRED $175,000 $175,000
CONCRETE STRUCTURES CUBIC YARD 575 $3,000 $1,725,000
SCREENS LUMP SUM ALL REQUIRED $100,000 $100,000
STOP LOGS LUMP SUM ALL REQUIRED $150,000 $150,000
GATE VALVES EACH 4 $15,000 $60,000
PENSTOCK $4,956,600.00
24" HDPE SDR 11 PIPE LINEAR FOOT 16,800 $235 $3,948,000
TRENCH INSULATION (4" BOARDSTOCK)SQUARE FOOT 134,400 $6.50 $873,600
GATE VALVES EACH 9 $15,000 $135,000
TAILRACE $375,700.00
36" HDPE SDR 11 PIPE LINEAR FOOT 850 $390 $331,500
TRENCH INSULATION (4" BOARDSTOCK)SQUARE FOOT 6,800 $6.50 $44,200
POWER HOUSE $3,250,000.00
FOUNDATION CUBIC YARD 400 $3,000 $1,200,000
BUILDING LUMP SUM ALL REQUIRED $500,000 $500,000
EQUIPMENT LUMP SUM ALL REQUIRED $1,550,000 $1,550,000
ACCESS ROAD $1,231,200.00
CLEARING AND GRUBBING ACRE 12.9 $20,000 $258,000
EXCAVATION CUBIC YARD 8,900 $15 $133,500
GEOTEXTILE (SEPARATION)SQUARE YARD 37,900 $3 $113,700
BORROW CUBIC YARD 17,200 $35 $602,000
12-INCH CULVERT LINEAR FOOT 360 $150 $54,000
24-INCH CULVERT LINEAR FOOT 280 $250 $70,000
ELECTRICAL TRANSMISSION $1,852,000.00
TRANSMISSION LINE LINEAR FOOT 21,200 $85 $1,802,000
TRANSFORMER EACH 2 $25,000 $50,000
MISCELLANEOUS $425,000.00
EROSION AND SEDIMENT CONTROL LUMP SUM ALL REQUIRED $200,000 $200,000
CONSTRUCTION SURVEYING LUMP SUM ALL REQUIRED $225,000 $225,000
$0
CONSTRUCTION SUBTOTAL: (SUM OF ABOVE) $17,485,500.00
BONDING AND INSURANCE: (5% OF CONSTRUCTION SUBTOTAL)5% $874,275
CONSTRUCTION ENGINEERING AND ADMINISTRATION: (6% OF ABOVE TWO ITEMS) 6% $1,101,587
CONTINGENCY: (25% OF ABOVE THREE ITEMS) 25% $4,865,340
TOTAL CONSTRUCTION PROJECT COSTS:$24,326,700.00
KOGOLUKTUK RIVER
ENGINEER'S CONCEPTUAL-LEVEL CONSTRUCTION COST ESTIMATE
ITEM DESCRIPTION UNIT
ESTIMATED
QUANTITY
UNIT
PRICE AMOUNT
MOBILIZATION $2,340,000.00
MOBILIZATION / DEMOBILIZATION LUMP SUM ALL REQUIRED $1,500,000 $1,500,000
WORKER MEALS AND LODGING (REMOTE CAMP)MAN-DAY 1,680 $500 $840,000
DIVERSION / INTAKE STRUCTURES $3,200,000.00
DEWATERING AND RIVER CONTROL LUMP SUM ALL REQUIRED $1,500,000 $1,500,000
ROCK ANCHORS LUMP SUM ALL REQUIRED $100,000 $100,000
CONCRETE STRUCTURES CUBIC YARD 450 $3,000 $1,350,000
SCREENS LUMP SUM ALL REQUIRED $50,000 $50,000
STOP LOGS LUMP SUM ALL REQUIRED $100,000 $100,000
GATE VALVES EACH 2 $50,000 $100,000
PENSTOCK $9,859,500.00
CLEARING (STEEP SLOPES)ACRE 8.9 $40,000 $356,000
BENCH EXCAVATION CUBIC YARD 68,700 $55 $3,778,500
72" HDPE WEHOLITE PIPE LINEAR FOOT 4,300 $1,300 $5,590,000
GATE VALVES EACH 3 $45,000 $135,000
TAILRACE $140,500.00
72" HDPE WEHOLITE PIPE LINEAR FOOT 100 $1,300 $130,000
TRENCH EXCAVATION & BACKFILL CUBIC YARD 700 $15 $10,500
POWER HOUSE $3,300,000.00
FOUNDATION CUBIC YARD 400 $3,000 $1,200,000
BUILDING LUMP SUM ALL REQUIRED $300,000 $300,000
EQUIPMENT LUMP SUM ALL REQUIRED $1,800,000 $1,800,000
ACCESS ROAD $4,037,500.00
CLEARING AND GRUBBING ACRE 27.2 $20,000 $544,000
EXCAVATION CUBIC YARD 33,200 $15 $498,000
GEOTEXTILE (SEPARATION)SQUARE YARD 104,000 $3 $312,000
BORROW CUBIC YARD 51,300 $45 $2,308,500
24-INCH CULVERT LINEAR FOOT 1,500 $250 $375,000
ELECTRICAL TRANSMISSION $2,974,000.00
TRANSMISSION LINE LINEAR FOOT 34,400 $85 $2,924,000
TRANSFORMER EACH 1 $50,000 $50,000
MISCELLANEOUS $275,000.00
EROSION AND SEDIMENT CONTROL LUMP SUM ALL REQUIRED $100,000 $100,000
CONSTRUCTION SURVEYING LUMP SUM ALL REQUIRED $175,000 $175,000
$0
CONSTRUCTION SUBTOTAL: (SUM OF ABOVE) $26,126,500.00
BONDING AND INSURANCE: (5% OF CONSTRUCTION SUBTOTAL)5% $1,306,325
CONSTRUCTION ENGINEERING AND ADMINISTRATION: (4% OF ABOVE TWO ITEMS) 4% $1,097,313
CONTINGENCY: (25% OF ABOVE THREE ITEMS) 25% $7,132,535
TOTAL CONSTRUCTION PROJECT COSTS:$35,662,700.00
PRECONSTRUCTION COSTS: Approx. 8.4% of Total Construction Costs 8.403%$2,996,797
(SURVEY, GEOTECHNICAL, ENVIRONMENTAL, DESIGN, PERMITTING)
TOTAL PROJECT DEVELOPMENT COSTS:$38,659,497
ITEM DESCRIPTION UNIT
UNIT
PRICE Source Notes
MOBILIZATION
MOBILIZATION / DEMOBILIZATION LUMP SUM Varies 5 (No. Herc Trips x $37,000/Trip) + ($300,000 to $400,000)
WORKER MEALS AND LODGING (REMOTE CAMP)MAN-DAY $500 5 Based on Man-Hour Estimates
DIVERSION / INTAKE STRUCTURES
DEWATERING AND RIVER CONTROL LUMP SUM $300,000 4 $50,000 at Kogoluktuk
ROCK ANCHORS LUMP SUM $75,000 4 Varies
CONCRETE STRUCTURES CUBIC YARD $3,000 1, 4, 5 See Calculations
SCREENS LUMP SUM $50,000 4 3 Times material quotes from vendors, Varies
STOP LOGS LUMP SUM $75,000 4 3 Times material quotes from vendors, Varies
GATE VALVES (24-INCH)EACH $15,000 4
GATE VALVES (72-INCH)EACH $45,000 4
PENSTOCK
CLEARING (STEEP SLOPES AT KOGOLUKTUK)ACRE $40,000 1, 5 See Calculations
BENCH EXCAVATION (BLASTING AT KOGOLUKTUK) CUBIC YARD $55 3, 5 See Calculations
24-INCH HDPE SDR 11 PIPE LINEAR FOOT $235 1, 4, 5, 6 See Calculations
72-INCH WEHOLITE PIPE LINEAR FOOT $1,300 1, 4, 5, 7 See Calculations
TRENCH INSULATION (4" BOARDSTOCK)SQUARE FOOT $6.50 2, 5 See Calculations
GATE VALVES EACH $12,000 4
TAILRACE
36" HDPE SDR 11 PIPE LINEAR FOOT $390 1, 4, 5, 6 See Calculations
TRENCH INSULATION (4" BOARDSTOCK)SQUARE FOOT $6.50 2, 5 See Calculations
POWER HOUSE
FOUNDATION CUBIC YARD $3,000 1, 4, 5 See Calculations
BUILDING LUMP SUM $300,000 9
EQUIPMENT LUMP SUM Varies 9
ACCESS ROAD
CLEARING AND GRUBBING ACRE $20,000 1, 5 See Calculations
EXCAVATION CUBIC YARD $15 1, 5 See Calculations
GEOTEXTILE (SEPARATION)SQUARE YARD $3 2
BORROW CUBIC YARD $35 1 See Calculations
24-INCH CULVERT LINEAR FOOT $250 2
ELECTRICAL TRANSMISSION
TRANSMISSION LINE LINEAR FOOT $85 8 Approx. $450,000/Mile
TRANSFORMER EACH $25,000 1
MISCELLANEOUS
EROSION AND SEDIMENT CONTROL LUMP SUM $100,000 5
CONSTRUCTION SURVEYING LUMP SUM $125,000 5
1 2006 RSMeans "Heavy Construction Cost Data 4 Ceila's Estimates
2 KIC Subdivision - Kaktovik (2012 Construction)5 Steve's Calculations
3 Shotgun Cove Road - Whittier (2011 Concstruction)6 Arctic Insulation Quote
Unit Cost Calculations
Concrete Volume:Excavation:
Assume Mix Volume Ratio of 1 : 2.5 : 2.5 : 0.5 (Cement : Sand : Aggregate : Water) Per 1 (02300-432-3220), Excavation w/ Dozer is $4.16/CY
Assume Concrete Volume = 2/3 of Individual Material Volumes Adjustment to RSMeans
1 CY Cement yields (0.67) x (1 + 2.5 + 2.5 + 0.5) = 4.33 CY Concrete Work in Anchorage = 133.7%
2.5 CY Aggregate yields (0.67) x (1 + 2.5 + 2.5 + 0.5) = 4.33 CY Concrete Work in Kobuk = 1.5 x Anchorage Costs
1 CY Concrete requires 0.23 CY Cement (1 CY Cement / 4.33 CY Concrete) Overtime Factor = 126.2%
1 CY Concrete requires 0.58 CY Sand or Aggregate (2.5 CY Aggr. / 4.33 CY Conc.) Inflation = 123%
1 CY Concrete requires 1.16 CY Sand and Aggregate (0.58 CY Sand + 0.58 CY Aggr.) Adjusted Installation Cost = $12.95/CY ($4.16 x 1.337 x 1.5 x 1.262 x 1.23); Use $15/CY
Concrete Unit Cost:Borrow:
Assume Sand and Gravel is obtained by screening on-site (@ $150/CY) Assume Dozer opens pit and stockpiles material
Assume 1 CF of Cement = 94 pounds; 1 CY Cement = 2,538 pounds Assume 2 Loads per hour
Assume Herc load of 44,000 pounds costs $37,000; 1 pound costs $0.84 Assume $3/CY royalty cost
Shipping Costs:Open Pit and Stockpile
1 CY Cement costs $2,132 (2,538 lbs x $0.84/lb) to ship Per 1 (02315-432-4000), Excavation w/ Dozer is $1.16/CY
1 CY Cement yields 4.33 CY Concrete Load Material
1 CY Concrete materials (cement) costs $492 ($2,132 / 4.33) to ship Per 1 (02315-210-5070), Loading w/ 3 CY Loader is $1.35/CY (Labor + Equip)
Material Costs:Haul Material
1 CY Concrete requires .23 CY Cement + 1.16 CY Aggregate Per 1 (02315-490-0400), Hauling w/ 12 CY Truck is $4.83/CY
1 CY Cement material costs $380 Spread Material
1 CY Aggregate material costs $150 Per 1 (02315-120-3000), Spreading Material w/ Dozer is $0.83/CY
1 CY Concrete materials costs $261 (.23 CY x $380 + 1.16 x $150) Compact Material
Installation Costs:Per 1 (02315-310-5000), Compacting Material is $0.35/CY
Per 1 (3310-240-4260), Concrete In-Place is $195/CY (Labor + Equipment) Unadjusted Borrow Costs are $8.52/LF ($1.16 + $1.35 + $4.83 + $0.83 + $0.35)
Adjustment to RSMeans Adjustment to RSMeans
Installation of Concrete in Anchorage = 115.2%Work in Anchorage = 133.7%
Installation in Kobuk = 6 x Anchorage Costs Installation in Kobuk = 1.5 x Anchorage Costs
Overtime Factor = 126.2%Overtime Factor = 126.2%
Inflation = 123%Inflation = 123%
Adjusted Installation Cost = $2,092 ($195 x 1.152 x 6 x 1.262 x 1.23) Royalty = Add $3/CY
Total Costs:Adjusted Cost = $29.52 [($8.52 x 1.337 x 1.5 x 1.262 x 1.23) + $3]; Use $35/CY
Total Concrete Cost = $2,845/CY ($492 + $261 + $2,092); Use $3,000/CY
Clearing (at Steep Slopes at Kogoluktuk):
Bench Excavation at Kogoluktuk:Assume 2x Regular Clearing Costs
Per 3, Drilling and Blasting Ecavation was $25/CY (in Whittier)Steep Clearing Costs are $40,000/Acre (2 x $20,000)
Assume 3% Inflation
Adjustments
Inflation Factor = 106.1%
Work occuring in Kobuk = 2 x Anchorage Costs
Adjusted Cost = $53.05/CY ($25/CY x 1.061 x 2); Use $55/CY
7 KWH Pipe Quote
8 AVEC
9 Dan's Estimates
24-Inch HDPE Cost:36-Inch HDPE Cost:
Assume Herc load of costs $37,000 Assume Herc load of costs $37,000
Assume Trench Volume is 1.85 CY/LF Assume Trench Volume is 2.57 CY/LF
Shipping Costs:Shipping Costs:
Herc can carry 1,350 LF of 24-Inch Pipe Herc can carry 450 LF of 36-Inch Pipe
1 LF of 24-Inch Pipe costs $27.41 ($37,000 / 1,350 LF) to ship; Use $28/LF 1 LF of 24-Inch Pipe costs $82.22 ($37,000 / 450 LF) to ship; Use $85/LF
Material Costs:Material Costs:
Pipe cost $80/LF (per 6)24-Inch HDPE Pipe cost $80/LF (per 6)
Installation Costs:Assume 36-Inch Pipe cost is 2x 24-Inch Pipe cost
Per 1 (02510-760-0900), 24-Inch HDPE is $29/LF (Labor + Equipment)36-Inch HDPE Pipe cost $120/LF
Per 1 (2315-610-0510), Trenching w/ 1 CY bucket is $3.54/CY Installation Costs:
Trenching is $6.55/LF ($3.54 x 1.85 CY/LF)Assume Installation cost 1.5x 24-Inch Pipe = 1.5 x $29/LF = $43.50/LF
Per 1 (2315-610-3080), Backfilling is $1.58/CY Per 1 (2315-610-0510), Trenching w/ 1 CY bucket is $3.54/CY
Backfilling is $2.92/LF ($1.58/CY x 1.85 CY/LF)Trenching is $9.10/LF ($3.54 x 2.57 CY/LF)
Per 1 (2315-310-7600), Compaction is $0.89/CY Per 1 (2315-610-3080), Backfilling is $1.58/CY
Compaction is $1.65/LF ($0.89/CY x 1.85 CY/LF)Backfilling is $4.06/LF ($1.58/CY x 2.57 CY/LF)
Unadjusted Installation Costs are $40.12/LF ($29 + $6.55 + $2.92 + $1.65)Per 1 (2315-310-7600), Compaction is $0.89/CY
Adjustment to RSMeans Compaction is $2.29/LF ($0.89/CY x 2.57 CY/LF)
Installation in Anchorage = 133.7%Unadjusted Installation Costs are $58.95/LF ($43.50 + $9.10 + $4.06 + $2.29)
Installation in Kobuk = 1.5 x Anchorage Costs Adjustment to RSMeans
Overtime Factor = 126.2%Installation in Anchorage = 133.7%
Inflation = 123%Installation in Kobuk = 1.5 x Anchorage Costs
Adjusted Installation Cost = $125 ($40.12 x 1.337 x 1.5 x 1.262 x 1.23)Overtime Factor = 126.2%
Total Costs:Inflation = 123%
Total 24-Inch Pipe Cost = $233/LF ($28 + $80 + $125); Use $235/LF Adjusted Installation Cost = $183.51 ($58.95 x 1.337 x 1.5 x 1.262 x 1.23); Use $185/LF
Total Costs:
Boardstock Insulation Cost:Total 36-Inch Pipe Cost = $390/LF ($85 + $120 + $185)
Assume Herc load of costs $37,000
Assume 4-Inch thick Insulation Clearing and Grubbing:
Shipping Costs:Per 1 (02230-100-0200), Cutting Medium Trees is $4,725/Ac
Herc can carry 5,540 CF of Boardstock Insulation Per 1 (02230-100-0250), Grubbing Medium Trees is $2,975/Ac
Insulation Units are SF of 4-Inch thickness Per 1 (02230-100-0400), If Burning is Allowed reduce by 40%
Herc can carry 16,620 SF of Board Insulation Cut, Grub, and Burn is $4,620 ($4,725/Ac + $2,975/Ac) x 0.6
1 SF of 4-Inch thick Insulation costs $2.23 ($37,000 / 16,620 SF) to ship Adjustment to RSMeans
Material Costs:Work in Anchorage = 133.7%
Insulation costs $4/SF (per 2)Work in Kobuk = 2 x Anchorage Costs
Installation Costs:Overtime Factor = 126.2%
Negligible Inflation = 123%
Total Costs:Adjusted Installation Cost = $19,176/Acre ($4,620 x 1.337 x 2 x 1.262 x 1.23); Use $20,000/Acre
Total Insulation Cost = $6.23/SF ($2.33 + $4 + $0); Use $6.50/SF
72-Inch HDPE Cost:
Assume Herc load of costs $37,000
Shipping Costs:
Herc can carry 150 LF of 72-Inch Pipe
1 LF of 74-Inch Pipe costs $247 ($37,000 / 150 LF) to ship; Use $250/LF
Material Costs:
Bare Pipe cost $350/LF (per 7)
Assume Insulation costs 2.5X Bare Pipe
Insulated Pipe Costs = $875/LF ($350 x 2.5)
Installation Costs:
Assume 100 LF/Day = 8.33 LF/Hr
Per 1 (02510-760), HDPE w/ Fused Joints use Crew B-22A
Crew B-22A is $2,516.20 per 8-hr day = $314.53/Hr
Unadjusted Installation Costs are $37.72/LF ($314.20/Hr / 8.33 LF/Hr)
Adjustment to RSMeans
Installation in Anchorage = 133.7%
Installation in Kobuk = 2 x Anchorage Costs
Overtime Factor = 126.2%
Inflation = 123%
Adjusted Installation Cost = $156.57/LF ($37.72 x 1.337 x 2 x 1.262 x 1.23); Use $160/LF
Total Costs:
Total 24-Inch Pipe Cost = $1,285/LF ($250 + $875 + $160); Use $1,300/LF