HomeMy WebLinkAboutHydroReconReport_PedroFINAL
H YDROELECTRIC R ECONNAISSANCE S TUDY
K NUTSON C REEK D RAINAGE,
T OWN C REEK, AND D UMBBELL L AKE
P EDRO B AY, ALASKA
F INAL R EPORT
OCTOBER 2009
Prepared For
PEDRO BAY VILLAGE COUNCIL
P.O. BOX 47020
PEDRO BAY, ALASKA 99647
By
POLARCONSULT ALASKA, INC.
1503 WEST 33RD AVENUE, SUITE 310
ANCHORAGE, ALASKA 99503
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT I
EXECUTIVE SUMMARY
In 2008, the Pedro Bay Village Council (PBVC) retained Polarconsult Alaska, Inc., (Polarconsult)
to complete a reconnaissance study of hydropower resources for the village of Pedro Bay.
Polarconsult evaluated six hydropower resources in the immediate vicinity of Pedro Bay.
These resources are:
Ø Knutson Creek Main Stem
Ø Knutson Creek Tributary R1 (1st major tributary on right looking upstream)
Ø Knutson Creek Tributary L1 (1st major tributary on left looking upstream)
Ø Knutson Creek Tributary R2 (2nd major tributary on right looking upstream)
Ø Cottonwood Creek
Ø Dumbbell Lake / Russian Creek
Of these resources, projects on the main stem of Knutson Creek or any of the first three major
tributaries of Knutson Creek appear technically feasible. A project on the main stem of Knutson
Creek looks most favorable, and could supply 100% of the community's existing electrical
generation, displacing 21,400 gallons of diesel fuel annually. This project could also displace
24,400 gallons of fuel used for space and water heating purposes. Economic analysis of this
project indicates a probable installed cost of $2.2 to 2.5 million for a 125 to 200 kW installation.
The 125 and 200 kW projects have estimated benefit cost ratios (BCRs) of 1.3 and 1.7. These
BCRs assume 90% of excess energy from the projects can be used by the community.
Projects on any of the three Knutson Creek tributaries could meet most of the community's
electrical demand, supplemented by diesel generation during winter months.
A project on Cottonwood Creek is also technically feasible, however this resource is much
smaller than the others and would only displace about 5,000 gallons of diesel fuel annually.
A project is not recommended at Dumbbell Lake / Russian Creek due to the probable conflict
with anadromous fish habitat and high cost of the project.
A feasibility study of the resources in the Knutson Valley is recommended to determine which
of the several promising hydropower resources in this area presents the best value for the
community. Key issues the feasibility study would address include:
Ø Hydrology (both for power generation and design flood),
Ø Permitting issues, including the extent and significance of anadromous fish habitat in
the main stem of Knutson Creek,
Ø Topographic and geotechnical surveys,
Ø Project sizing and integration with the community's energy infrastructure to utilize all of
the available energy,
Ø Project financing, and
Ø Construction methods and costs.
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT II
TABLE OF CONTENTS
EXECUTIVE SUMMARY .........................................................................................................................................I
TABLE OF CONTENTS ..........................................................................................................................................II
ACRONYMS AND TERMINOLOGY ..................................................................................................................V
1.0 INTRODUCTION .......................................................................................................................................1
1.1 PROJECT AUTHORIZATION AND PURPOSE ................................................................................................1
1.2 COMMUNITY BACKGROUND......................................................................................................................1
1.3 PROPOSED ENERGY RESOURCES ................................................................................................................3
1.4 SUMMARY OF PREVIOUS STUDIES ..............................................................................................................3
2.0 EXISTING ENERGY SYSTEM .................................................................................................................4
2.1 COMMUNITY ENERGY PROFILE .................................................................................................................4
2.2 ELECTRIC UTILITY ORGANIZATION...........................................................................................................4
2.3 GENERATION SYSTEM ................................................................................................................................4
2.4 ELECTRICAL DISTRIBUTION SYSTEM ..........................................................................................................5
2.5 EXISTING AND PROJECTED FUTURE LOAD PROFILE ..................................................................................5
2.6 PLANNED UPGRADES.................................................................................................................................5
2.7 ENERGY MARKET .......................................................................................................................................5
3.0 PROPOSED ENERGY RESOURCES .......................................................................................................6
3.1 RESOURCE DESCRIPTIONS ..........................................................................................................................6
3.1.1 Knutson Creek – Main Stem .................................................................................................................6
3.1.2 Knutson Creek – Tributary R1 ..............................................................................................................8
3.1.3 Knutson Creek – Tributary L1 ..............................................................................................................8
3.1.4 Knutson Creek – Tributary R2 ..............................................................................................................9
3.1.5 Cottonwood Creek ..................................................................................................................................9
3.1.6 Dumbbell Lake / Russian Creek ...........................................................................................................10
3.2 HYDROLOGY ............................................................................................................................................10
3.3 GEOTECHNICAL / GEOMORPHOLOGICAL CONSIDERATIONS .................................................................14
3.4 PROJECT LANDS .......................................................................................................................................14
3.4.1 Knutson Valley Projects ......................................................................................................................14
3.4.2 Site Control Requirements...................................................................................................................15
4.0 PROPOSED PROJECT DESIGN ............................................................................................................16
4.1 ANALYSIS OF PROJECT ALTERNATIVES ...................................................................................................16
4.1.1 Hydropower Resources ........................................................................................................................16
4.1.2 Installed Capacity ................................................................................................................................17
4.2 RECOMMENDED PROJECT ........................................................................................................................18
4.3 ANNUAL ENERGY PRODUCTION .............................................................................................................18
4.4 CONCEPTUAL SYSTEM DESIGN ................................................................................................................19
4.4.1 Project Access ......................................................................................................................................19
4.4.2 Intake ...................................................................................................................................................19
4.4.3 Penstock ...............................................................................................................................................19
4.4.4 Powerhouse ..........................................................................................................................................20
4.4.5 Power Line ...........................................................................................................................................20
4.4.6 Controls ...............................................................................................................................................20
4.5 CONCEPTUAL INTEGRATION DESIGN......................................................................................................21
4.6 REMAINING TECHNICAL CONSIDERATIONS ...........................................................................................21
4.6.1 Hydrology ............................................................................................................................................21
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT III
4.6.2 Installed Capacity ................................................................................................................................22
4.6.3 Existing Electric System Constraints..................................................................................................22
4.6.4 Financing .............................................................................................................................................22
4.6.5 Geotechnical / Topographic Considerations.........................................................................................23
4.6.6 Permits.................................................................................................................................................23
4.6.7 Feasibility Study ..................................................................................................................................23
5.0 ECONOMIC ANALYSIS .........................................................................................................................24
5.1 ANNUAL PROJECT COSTS ........................................................................................................................25
5.1.1 Operation and Maintenance ................................................................................................................25
5.1.2 Repair and Replacement ......................................................................................................................25
5.1.3 Property ...............................................................................................................................................26
5.1.4 Taxes ....................................................................................................................................................26
5.1.5 Insurance .............................................................................................................................................26
5.1.6 Financing .............................................................................................................................................26
5.2 PROJECT REVENUES AND SAVINGS..........................................................................................................26
5.2.1 Direct Fuel Displacement ....................................................................................................................26
5.2.2 Excess Energy ......................................................................................................................................26
5.2.3 Environmental Attributes ...................................................................................................................27
5.2.4 Indirect and Non-Monetary Benefits...................................................................................................27
6.0 PERMITS ....................................................................................................................................................29
6.1 FEDERAL PERMITS ....................................................................................................................................29
6.1.1 FERC ...................................................................................................................................................29
6.1.2 U.S. Army Corps of Engineers Permits ..............................................................................................29
6.1.3 U.S. Environmental Protection Agency ..............................................................................................29
6.1.4 Federal Aviation Administration ........................................................................................................29
6.2 STATE OF ALASKA PERMITS .....................................................................................................................29
6.2.1 Department of Natural Resources Permits..........................................................................................29
6.2.2 Department of Fish and Game Permits ...............................................................................................30
6.2.3 Department of Transportation Permits ...............................................................................................30
6.2.4 Department of Environmental Conservation Permits.........................................................................30
6.3 LOCAL PERMITS .......................................................................................................................................30
7.0 ENVIRONMENTAL CONSIDERATIONS ..........................................................................................31
7.1 THREATENED AND ENDANGERED SPECIES .............................................................................................31
7.2 FISHERIES AND WILDLIFE ........................................................................................................................31
7.3 WATER AND AIR QUALITY ......................................................................................................................31
7.4 WETLAND AND PROTECTED AREAS ........................................................................................................31
7.5 ARCHAEOLOGICAL AND HISTORICAL RESOURCES .................................................................................31
7.6 LAND DEVELOPMENT CONSIDERATIONS................................................................................................31
7.7 TELECOMMUNICATIONS AND AVIATION ................................................................................................32
7.8 VISUAL AND AESTHETICS RESOURCES ....................................................................................................32
7.9 MITIGATION MEASURES ..........................................................................................................................32
8.0 FINDINGS AND RECOMMENDATIONS .........................................................................................33
8.1 FINDINGS..................................................................................................................................................33
8.2 DEVELOPMENT PLAN & SCHEDULE ........................................................................................................33
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT IV
LIST OF FIGURES
Figure 1-1: Project Overview and Location Map ..................................................................................2
Figure 3-1: Aerial View of Knutson Creek in Vicinity of Proposed Project Intake Site ..................6
Figure 3-2: Location of Hydropower Resources near Pedro Bay .......................................................7
Figure 3-3: Aerial View of Knutson Creek Tributary R1 in Vicinity of Proposed Project
Intake Site ...............................................................................................................................8
Figure 3-4: View of Knutson Creek ........................................................................................................8
Figure 3-5: Cottonwood Creek in the vicinity of the intake site looking upstream........................9
Figure 3-5: Drainage Basins Near Pedro Bay with USGS Discharge Gauges .................................11
Figure 3-6: Normalized Discharge from USGS-Gauged Basins Near Pedro Bay ..........................12
Figure 8-1: Project Development Schedule ..........................................................................................34
LIST OF TABLES
Table 1-1: Previously Identified Hydropower Resources Near Pedro Bay .......................................3
Table 2-2: Existing Utility Generation Equipment ...............................................................................5
Table 3-1: Summary of Hydropower Resources near Pedro Bay .......................................................6
Table 3-2: Hydrologic Information for Pedro Bay Hydropower Resources ...................................12
Table 3-3: Stream Discharge Data for Local Hydropower Resources .............................................13
Table 4-1: Technical Parameters of Potential Hydropower Developments near Pedro
Bay .........................................................................................................................................16
Table 4-2: Comparison of 125 kW and 200 kW Developments at Knutson Creek.........................18
Table 5-1: Summary of Economic Data for Recommended Hydroelectric Projects ......................24
Table 5-2: Estimated Electric Rates with Hydro Projects ..................................................................25
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT V
ACRONYMS AND TERMINOLOGY
ADCED Alaska Department of Community and Economic Development
ADEC Alaska Department of Environmental Conservation
ADFG Alaska Department of Fish and Game
ADNR Alaska Department of Natural Resources
AEA Alaska Energy Authority
AEA / REG Alaska Energy Authority Rural Energy Group
AEE Alaska Energy and Engineering, Inc.
cfs cubic feet per second
coanda effect The tendency of a fluid jet to stay attached to a smoothly convex solid
obstruction. A common example is the way a stream of water, as from a faucet,
will wrap around a cylindrical object held under the faucet (such as the barrel of
a drinking glass).
COE U.S. Army Corps of Engineers
CPCN Certificate of Public Convenience and Necessity
Environmental attributes
The term environmental attributes is used by the green power industry to
describe the desirable aspects of electricity that is generated by environmentally
benign and/or renewable sources. Environmental attributes are tracked,
marketed, bought and sold separately from the physical energy. Separating the
environmental attributes enables customers on a given utility system to elect to
buy sustainable or ‘green’ energy even if it is unavailable from their utility.
ft foot, feet
FY fiscal year
HDPE high-density polyethylene
in inch, inches
kV kilovolt, or 1,000 volts
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT VI
kVA kilovolt-amp
kW kilowatt, or 1,000 watts. One kW is the power consumed by ten 100-watt
incandescent light bulbs.
kWh kilowatt-hour. The quantity of energy equal to one kilowatt (kW) expended for
one hour.
LIDAR Light Detection and Ranging
LPSD Lake and Peninsula School District
mi mile, miles
MW megawatt, or 1,000 kilowatts
NEC National Electric Code
NESC National Electric Safety Code
PBC Pedro Bay Corporation, Inc.
PBEU Pedro Bay Electric Utility
PBVC Pedro Bay Village Council
PCA Polarconsult Alaska, Inc.
PCE Power Cost Equalization Program
Polarconsult Polarconsult Alaska, Inc.
Plant capacity factor
The plant capacity factor is the amount of energy a power plant is likely to
produce in a year divided by the amount of energy the plant would produce if it
operated at 100% capacity continuously. Capacity factor is expressed as a
percentage, and is usually less than 100% for renewable energy because the
resource (water, wind, sun, etc.) is not always available.
PLC programmable logic controller
RCA Regulatory Commission of Alaska
SDR strength-dimension ratio.
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT VII
USGS U.S. Geological Survey
V volt
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT 1
1.0 INTRODUCTION
1.1 PROJECT AUTHORIZATION AND PURPOSE
In December 2008, the Pedro Bay Village Council (PBVC) retained Polarconsult Alaska, Inc.
(PCA) to complete a reconnaissance study of hydropower resources that might provide
economical electricity for Pedro Bay. The purpose of this reconnaissance study is to identify
potential hydropower resources suitable for Pedro Bay and to conduct an initial review and
analysis of these resources to determine if more detailed study is warranted. The principal
objectives of the reconnaissance study are (1) an opinion of whether further study is warranted
and (2) specific recommendations for further study.
After completing review of existing materials and information pertinent to potential
hydropower resources near Pedro Bay, Polarconsult engineer Joel D. Groves, P.E., visited Pedro
Bay on July 20-24, 2009 to conduct reconnaissance-level field investigations of several local
hydropower resources. Reconnaissance investigations in Pedro Bay included gathering
information on the existing electrical system and load profile, visiting proposed hydro sites,
measuring stream flows, and collecting basic topographic data. This information is presented in
this report and is used to arrive at recommendations for further study.
This report summarizes the findings of Polarconsult's reconnaissance investigations and
Polarconsult’s recommendations for further project development. This report is the final
deliverable for the Reconnaissance Study.
1.2 COMMUNITY BACKGROUND
Pedro Bay, population 62, is an unincorporated community located at the east end of Iliamna
Lake in southwest Alaska. It is located at 598 47.23' North, 1548 6.37' West, which is about 175
miles southwest of Anchorage, 165 miles west of Dillingham, and 90 miles east of Homer.
Pedro Bay is located in a transitional climate zone characterized by both continental and
maritime climates. Normal summer temperatures range from the lower 40s to lower 60s,
normal winter temperatures range from around 6 to 308F. Average annual rainfall is 26 inches,
average annual snowfall is 64 inches.
The community is accessible by air via a state owned airstrip, and by water via Iliamna Lake.
Barge service is available from Naknek via the Kvichak River and Iliamna Lake. Goods can also
shipped to Iliamna Bay on lower Cook Inlet, and then portaged over the Pile Bay Road to Pile
Bay on Lake Iliamna, where they are then barged to Pedro Bay. Figure 1-1 indicates Pedro Bay's
location in Alaska and surroundings. 1
1 Compiled from ADCED Community Profile for Pedro Bay.
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT 3
Pedro Bay is located in the Lake & Peninsula School District (LPSD), and the local school
teaches 12 students in grades P through 12. The Village Council operates a Class III landfill,
29,500-gallon bulk fuel facility, and the local power plant and electric system.
1.3 PROPOSED ENERGY RESOURCES
Six hydropower resources in the immediate vicinity of Pedro Bay warranted reconnaissance-
level investigation for hydropower development. These resources are listed below, and
discussed in detail in Section 3:
Ø Knutson Creek
Ø Knutson Creek Tributary R1 (first major tributary on right looking upstream)
Ø Knutson Creek Tributary L1 (first major tributary on left looking upstream)
Ø Knutson Creek Tributary R2 (second major tributary on right looking upstream)
Ø Dumbbell Lake / Russian Creek
Ø Cottonwood Creek
1.4 SUMMARY OF PREVIOUS STUDIES
Hydropower resources in the vicinity of Pedro Bay were investigated as part of a regional
reconnaissance study completed for the U.S. Army Corps of Engineers (COE) in April 1981.
The COE considered 100-kW run -of-river hydroelectric projects on Knutson Creek and Canyon
Creek. Technical aspects of these projects are summarized in Table 1-1.
Table 1-1: Previously Identified Hydropower Resources Near Pedro Bay
Attribute Canyon Creek Knutson Creek
Basin Area 24.5 square miles 29.4 square miles
Estimated Average Flow 98 cfs 117.6 cfs
Plant Design Flow 30 cfs 30 cfs
Gross Head 50 feet 50 feet
Installed Capacity 100 kW 100 kW
Dan Height 20 feet 20 feet
Penstock Length 500 feet 700 feet
Penstock Diameter 30 inches 32 inches
Transmission Line Length 10 miles 3 miles
Installed Cost (1980 dollars) $4,772,000 $4,517,000
Cost-Benefit Ratio 0.30 0.31
Table condensed from Tables V-15 through V-17, Small Scale Hydropower Reconnaissance Study
Southwest Alaska, COE, 1981.
The COE found both of these projects to be uneconomical. The COE’s use of relatively large
dams for these micro-scale hydro developments likely contributed to this conclusion. In spite of
the COE’s findings, there are promising hydropower resources in the vicinity of Pedro Bay.
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT 4
2.0 EXISTING ENERGY SYSTEM
2.1 COMMUNITY ENERGY PROFILE
Pedro Bay's energy infrastructure underwent a significant upgrade in about 2004. At this time,
separate electrical generation and bulk fuel operations for the school and community were
consolidated, enabling lower operating costs, higher generation efficiency, and better utilization
of waste heat at the school. 2
Pedro Bay's peak annual combined gasoline and diesel usage was estimated in 2003 to be 64,500
gallons. This is the total fuel consumed by the community, and includes fuel for electrical
generation, heating, and transportation. Of this, the diesel power plant uses about 21,000
gallons annually. 2 Waste heat from the power plant is used to heat the school. This has been
estimated to save 11,000 gallons of heating fuel annually. 3
2.2 ELECTRIC UTILITY ORGANIZATION
Electrical service in Pedro Bay is provided by the Pedro Bay Village Council (PBVC). The PBVC
holds Certificate of Public Convenience and Necessity (CPCN) No. 662 authorizing it to operate
a public utility providing electrical service in and around Pedro Bay. The CPCN was issued by
the Regulatory Commission of Alaska (RCA) in 2002. The RCA has exempted PBVC from rate
regulation on a public interest basis as allowed by AS 42.05.711(d).
PBVC participates in the state of Alaska’s Power Cost Equalization (PCE) program, which
subsidizes electricity rates for residential and community facilities served by eligible Alaska
utilities.
2.3 GENERATION SYSTEM
PBVC's power plant is located at the school. The plant has three generators controlled by four
sections of switchgear. The switchgear is fully automatic with paralleling capability, and uses a
PLC to match the generator(s) to system load. The plant generates at 480V single phase. The
generation assets are generally in good condition - all major assets are less than ten years old.
A fourth generator is located immediately adjacent to the PBVC gensets, and is dedicated to
emergency power for the school. This generator feeds the school through a manual transfer
switch, and is not configured to power the community. Installed generation equipment in
Pedro Bay is listed in Table 2-2.
2 State of Alaska Power Cost Equalization Program Annual Report, Alaska Energy Authority, 2002 – 2008.
3 Concept Design Report and Construction Cost Estimate for Consolidation and Renovation of Fuel Storage and
Electrical Generation Facilities in the Community of Pedro Bay, Report for AEA/REG, Prepared by Alaska
Energy and Engineering, Inc. 2003.
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT 5
Table 2-2: Existing Utility Generation Equipment
No. Equipment Prime
Power (kW)
Commissioned
Date Use
1 John Deere #6059TFG01 Engine w/
Newage Generator 125 kW 2000 Utility
2 John Deere #4045T150 w/ Magnaplus Generator 60 kW 2001 Utility
3 John Deere #4045T150 w/ Magnaplus Generator 60 kW 2001 Utility
4 John Deere #4045T150 60 kW 2001 School Backup
2.4 ELECTRICAL DISTRIBUTION SYSTEM
The PBVC distribution system is a 7,200V single-phase buried cable system. 480 V at the power
plant is stepped up to 7,200V with a 100 kVA transformer.
2.5 EXISTING AND PROJECTED FUTURE LOAD PROFILE
Pedro Bay's population and economy have been relatively stable for many years. Future electric
loads are expected to be relatively flat. If the hydroelectric plant significantly reduces electricity
rates, the system load may increase as the community transitions from wood and fuel oil to
electricity for space and water heating.
2.6 PLANNED UPGRADES
The bulk fuel and electrical generation systems were recently upgraded. No upgrades to the
electric utility system are planned.
2.7 ENERGY MARKET
Energy from a local hydroelectric project would be fed into the Pedro Bay Electric Utility to
offset or replace diesel power generation. If a hydroelectric project generates energy in excess
of electrical demand, other energy utilization such as space heating or water heating to displace
fuel oil and/or wood burning is possible.
The current cost of electricity in Pedro Bay is $0.91 per kWh. It was raised from $0.60 per kWh
in late 2008 to reflect increases in the price of fuel. PCE subsidies reduce the cost of electricity
for residential accounts (up to 500 kWh monthly) to the range of $0.20 to 0.40 per kWh. The
subsidized rate varies depending on how much money the State of Alaska appropriates for the
PCE program.
Fuel is delivered to Pedro Bay by plane and by barge. In recent years PBVC has relied
increasingly on airborne fuel deliveries because the reliability and frequency of fuel barge
service has decreased. Fuel costs have increased from an average of $2.17 per gallon in 2002 –
2004 to an average of $4.17 per gallon in 2006 – 2008. The cost of fuel averaged $5.72 per gallon
in FY 2008.
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT 6
3.0 PROPOSED ENERGY RESOURCES
3.1 RESOURCE DESCRIPTIONS
There are six hydropower resources in the vicinity of Pedro Bay that were studied. Key
attributes for the six resources are summarized in Table 3-1. The locations of these projects are
indicated on Figure 3-2.
Table 3-1: Summary of Hydropower Resources near Pedro Bay
Parameter Knutson
Creek Main Knutson R1 Knutson L1 Knutson R2 Cottonwood
Creek
Dumbbell
Lake
Intake Elevation (ft) 400 500 750 800 320 250
Gross Head (ft) 200 350 500 350 215 190
Penstock Length (ft) 4,700’ 3,400’ 4,800’ 3,500’ 2,200’ 8,100’
Transmission Length (mi) 1.6 1.2 1.8 3.9 0.2 0.6
Note: All values are approximate and intended only for reconnaissance-level resource screening.
3.1.1 Knutson Creek – Main Stem
This project would be located on the main stem of Knutson Creek. The powerhouse would be
located about one mile upstream from the end of the runway, and the intake would be located
9/10ths of a mile farther upstream. The project would develop about 200 feet of head, and would
use about 14 cubic feet per second (cfs) of water for an installed capacity of about 125 kW, or 22
cfs for an installed capacity of 200 kW .
Available hydrology data indicates that Knutson Creek may be able to provide the full design
flow for a 125 kW project year-
round. Development of this
resource can meet 100% of the
community’s existing electricity
demand, and could also
provide a significant amount of
additional energy for space
heating, water heating, and
other productive uses. If the
community can absorb more
than 125 kW of output, a larger
project at this location may be
warranted. Project size is a key
issue for the feasibility study.
Figure 3-1: Aerial View of Knutson Creek in Vicinity of
Proposed Project Intake Site
Proposed Intake Site on
Knutson Creek Direction of Flow
To Pedro Bay
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT 8
Proposed Intake
Location Vicinity
Location of 7/22/09
Stream Flow
Measurement
3.1.2 Knutson Creek – Tributary R1
This project would be located on the first major tributary of Knutson Creek on the right side
looking upstream. It would have a gross head of about 350 feet and design flow of 6.6 cfs for an
output of 125 kW. Full output would be available for most of the summer months. Minimum
output during the winter months and summer-time dry spells in an average year would be
approximately 20 kW. During extreme dry spells, the project could be briefly shut down for
lack of water. With this
project, Pedro Bay could shut
down its diesel generators
much of the time, but they
would need to be operated in
parallel with the hydro for
most of the winter and during
dry periods of the summer.
This resource has the shortest
access and power line from
Pedro Bay, resulting in lower
capital costs than other options
in the Knutson Creek valley.
This project would generate
less energy than other projects,
so its potential value to the
community is somewhat less
than for other project options.
Figure 3-3: Aerial View of Knutson Creek Tributary R1 in
Vicinity of Proposed Project Intake Site
3.1.3 Knutson Creek – Tributary L1
This project would be located on the first major
tributary of Knutson Creek on the left looking
upstream. It would have a gross head of about
500 feet and a design flow of 4.7 cfs for an
installed capacity of 125 kW. Minimum power
generation during low flows is estimated to be
about 10 kW.
Figure 3-4: View of Knutson Creek
Tributary L1 From Pedro Bay Airport
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT 9
3.1.4 Knutson Creek – Tributary R2
This project would be very similar to development of Tributaries R1 or L1, only it is located
farther away from Pedro Bay and in more rugged terrain. Accordingly, expected development
costs for this project would be higher than for Tributary L1, and this project warrants
consideration only in the event that development of other options are determined to not be
feasible.
3.1.5 Cottonwood Creek
This project would be located on Cottonwood Creek, just behind Pedro Bay. The intake would
be located in a small canyon less than 1,000 feet from existing residential development in the Big
Hill subdivision, and the powerhouse would be located adjacent to an existing road. The
project would have gross head of about 215 feet and a design flow of about 3 cfs, for an output
of up to about 30 kW. During the winter months, the project may be shut down for lack of
water.
This project would be a good energy supply
for the community, however development of
larger projects in the Knutson Valley appears
favorable, and these projects would provide
significantly more energy for the community.
In the event that development of hydropower
resources in the Knutson Valley are not
feasible, development of Cottonwood Creek
should be further investigated.
Figure 3-5: Cottonwood Creek in the vicinity
of the intake site looking upstream.
Note exposed bedrock cliff at right. The creek is
incised in a canyon 30 to 50 feet deep in this vicinity.
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT 10
3.1.6 Dumbbell Lake / Russian Creek
This project would be located at or near the outlet of Dumbbell Lake into Russian Creek. It
would have a head of up to 190 feet and a flow of about 12 cfs for an installed capacity of 125
kW. Regulation of the lake could enable peak power generation at any time during the year.
This resource is not considered further in this study for the following reasons:
· The project would require a relatively long, large diameter penstock. This will make the
project more expensive compared to other projects.
· Russian Creek, Dumbbell Lake, and the lake’s feeder streams are designated by the
Alaska Department of Fish and Game (ADFG) as anadromous habitat for sockeye
salmon. 4 Reconciling the need to regulate the lake level for power generation with the
need to maintain fish passage and fish habitat makes this project problematic.
In the event that future study of more favorable hydropower resources identified in this study
determines that they are not feasible, this resource may warrant reconsideration.
3.2 HYDROLOGY
The hydrology of the identified hydropower resources needs to be measured or characterized in
order to calculate how much energy the resources can provide. It is also necessary to properly
design the hydroelectric development so it does not get damaged by floods. Also, hydrology
information is necessary to assess the effect hydropower development may have on the natural
environment.
The USGS maintains stream gauging stations on several streams in the Iliamna Lake region that
may have similar hydrology as the hydropower resources near Pedro Bay. Stream flow
measurements have also been collected at Knutson Creek and Russian Creek as part of
environmental studies conducted by Bristol Environmental Services (BES) for potential
transportation corridors to the proposed Pebble Mine. Polarconsult also collected stream flow
data during field reconnaissance in July 2009. This information can be used to develop initial
estimates of hydrology for the identified hydropower resources. Existing hydrologic
information is summarized in Table 3-2. The drainage basins associated with the gauge / intake
site locations listed in Table 3-2 are indicated in Figure 3-5. Normalized discharge (cfs per
square mile) for the four USGS-gauged basins are presented in Figure 3-6.
4 Atlas of Waters Important for the Spawning, Rearing or Migration of Anadromous Fishes, ADFG, 2009.
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT 12
Table 3-2: Hydrologic Information for Pedro Bay Hydropower Resources
Location USGS
Gauge ID
Basin
Size
(sq mi)
Site
Elevation
(ft)
Latitude
(NAD27)
Longitude
(NAD 27)
Begin
Date
End
Date
Number
of Daily
Records
Bear Creek 15300100 2.6 250 59849'28" 154852'56" 7/23/05 9/1/09 1 1,501
Roadhouse Creek 15300200 20.8 62 59845'26" 154850'49" 5/1/05 9/1/09 1 1,584
Upper Talarik
River 15300250 86.6 425 59847'12" 155815'11" 8/25/04 9/1/09 1 1,833
Iliamna River 15300300 128 80 59845'31" 153850'41" 5/24/96 9/1/09 1 4,848
Knutson Creek - 33.8 80 59848'15" 154808'26" 7/21/04 10/7/05 11 2
Knutson Creek
Intake - 27.6 400 59849'42" 154806'21" - - -
Knutson Creek
R1 Intake - 2.7 400 59848'44" 154806'28" 7/21/09 - 1 3
Knutson Creek
L1 Intake - 1.5 800 59849'45" 154807'35" - - -
Knutson Creek
R2 Intake - 3.7 1,000 59849'32" 154805'03" - - -
Cottonwood
Creek Intake - .065 400 59847'28" 154805'26" 7/20/09 7/22/09 2 3
Russian Creek /
Dumbbell Lake - 2.2 200 59846'31" 154802'37" 7/21/04 4/3/05 6 2
1. Sites are currently equipped by USGS with real-time gauges.
2. Instantaneous discharge measurements reported by BES. Measurement locations are assumed.
3. Instantaneous discharge measurements by Polarconsult.
Figure 3-6: Normalized Discharge from USGS-Gauged Basins Near Pedro Bay
0
1
2
3
4
5
6
7
8
9
10
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov DecNormalized Basin Discharge(cfs per square mile)Iliamna
Bear
Upper Talarik
Roadhouse
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT 13
The discharge measurements taken by BES at Knutson Creek are the best available discharge
data for Knutson Creek and its tributaries. Of the four USGS gauges near Pedro Bay, the
Iliamna River discharge dataset, which extends to the present day, is the best dataset to
compare to Knutson Creek. The Iliamna River dataset can be scaled to estimate discharge in
Knutson Creek and its tributaries. This allows prediction of the amount of power that can be
generated from these resources.
The 11 discharge measurements at Knutson Creek have a correlation coefficient of 0.877 with
the corresponding daily discharge data for Iliamna River. This is a very good correlation,
indicating that these two basins likely have very similar discharge patterns. This means that
Knutson Creek discharge can probably be predicted with high confidence using Iliamna River
data. Unfortunately, the confidence of these findings is limited because there are only 11 data
points. More discharge data or more detailed statistical analysis of existing data is needed to
increase the confidence in conclusions drawn from these data.
Polarconsult measured discharge in Cottonwood Creek and Knutson tributary R1 in July 2009.
These and other flow data are summarized in Table 3-3.
Table 3-3: Stream Discharge Data for Local Hydropower Resources
Resource Measurement
Date/Time
Measured
Flow (cfs)
Normalized Flow
(cfs per square
mile)
Concurrent Iliamna
River Normalized Flow
(cfs per square mile)
Knutson Creek 7/21/2004 128.6 4.5 7.8
Knutson Creek 8/18/2004 63.52 2.2 3.3
Knutson Creek 9/24/2004 69.67 2.4 3.0
Knutson Creek 10/16/2004 282.35 9.9 8.0
Knutson Creek 2/17/2005 27.34 1.0 1.3
Knutson Creek 4/3/2005 16.03 0.6 1.3
Knutson Creek 5/4/2005 247.67 8.7 8.6
Knutson Creek 6/14/2005 314.31 11.0 16.2
Knutson Creek 7/15/2005 167.31 5.9 9.1
Knutson Creek 8/9/2005 116.83 4.1 4.0
Knutson Creek 10/7/2005 167.53 5.9 4.1
Knutson Creek
Tributary R1 7/22/09 1:50 PM 43.5 19.8 46.6
Cottonwood Creek 7/20/09 4:35 PM 3.08 47.4 13.1
Cottonwood Creek 7/20/09 4:50 PM 3.09 47.4 13.1
Cottonwood Creek 7/22/09 4:45 PM 5.68 87.4 46.6
Russian Creek 7/21/2004 4.19 1.9 7.8
Russian Creek 8/19/2004 2.24 1.0 3.1
Russian Creek 9/24/2004 2.32 1.1 3.0
Russian Creek 10/15/2004 6.21 2.8 9.9
Russian Creek 2/16/2005 3.56 1.6 1.3
Russian Creek 4/3/2005 3.01 1.4 1.3
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT 14
3.3 GEOTECHNICAL / GEOMORPHOLOGICAL CONSIDERATIONS
The project areas are characterized by very thin organic soils over a mantle of granular deposits
of varying depths. Bedrock is exposed in the upper elevations and around most intake sites.
Based upon field observations, excavations and benching is possible on most moderate side
slopes using conventional methods. Blasting could be required in some areas if competent rock
is encountered. More specific geotechnical investigations are necessary as part of the feasibility
study for the project.
Field observations along Knutson Creek indicate it is an active stream with high flood flows and
high bed loads. Knutson Creek broke out of its current channel in the past decade or so,
causing damage to the airport and temporarily discharging into the wetland area located
between Pedro Bay and the airport. A dike was built to relocate the creek to its channel.
Observation of the terrain upstream from this dike suggests that the creek could again breach its
natural confines and head towards the airport in a future flood. Floods in this area could affect
project access, power line, and the powerhouse.
Upstream of this area, where the hydro project penstock and intake would be located, the creek
is confined to its channel by topography and bedrock. The intake structure would still need to
handle flood flows and debris.
Field observations along Knutson tributary R1 indicate it is also an active stream with high
flood flows and high bed loads. The creek is incised in a bedrock canyon up in the intake
vicinity, but on the lower slopes it is confined to an incised valley with a broad floor. Within
this valley, the creek appears to shift course about every decade, judging from the willow and
alder growth observed in old creek beds. The creek bed in this area consists of stones and
boulders from 6-inch to 3-foot in size and larger. Site topography allows the penstock to
rapidly depart this valley, so only the intake and upper several hundred feet of penstock would
need to consider flood and channel shifting hazards. The powerhouse site would need to
consider flood hazards associated with Knutson Creek.
Access to the Knutson Valley sites is good. There appears to be abundant granular materials for
trail construction, and very little exposed bedrock in the lower Knutson Valley. Some bedrock
will likely be encountered on the upper portion of penstock routes and at the intake sites for
any of the Knutson Valley projects.
3.4 PROJECT LANDS
3.4.1 Knutson Valley Projects
All three hydropower resources in the Knutson Valley are located on lands that have been
interim-conveyed from the Bureau of Land Management (BLM) to Pedro Bay Corporation
(PBC). The overland access and power transmission routes between Pedro Bay and these
resources have also been interim-conveyed to PBC. If a separate beach landing and materials
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT 15
haul route is desired from Knutson Bay directly up to these project locations, Access across USS
7333 or USS 4821 could be necessary. If the power line is extended from the airport
sectionalizing cabinet, it would need to cross the airport property en route to any of the
Knutson Valley power house sites.
3.4.2 Site Control Requirements
A hydroelectric project will require clear title to the lands it occupies. This includes the
intake/diversion structure footprint, penstock alignment, powerhouse and tailrace footprint,
transmission line alignment, and access trails or roads. Title to these lands can take a variety of
forms. Some typical methods are listed below:
Ø Easements. Some or all of the project lands can be secured by easement. Public or
private easements can be used in accordance with the preferences of the parties
involved.
Ø Leases. Some or all of the project lands can be secured by long-term leases. A lease term
of 50 years or with favorable renewal provisions is recommended due to the long
economic life of a hydroelectric development.
Ø Land transfer or purchase.
Title to different parts of the project may be secured by different means. One typical
arrangement is to purchase or lease the intake and powerhouse footprints and to secure
easements for penstock, access, and transmission corridors.
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT 16
4.0 PROPOSED PROJECT DESIGN
4.1 ANALYSIS OF PROJECT ALTERNATIVES
4.1.1 Hydropower Resources
Of the six hydropower resources identified in the vicinity of Pedro Bay, only the four resources
located in the Knutson Valley are considered. Cottonwood creek appears to be a viable
resource, but is very small – the Knutson Valley resources offer superior benefits to the village.
The Dumbbell Lake project would be expensive due to its long penstock, and would also likely
be difficult to permit due to the presence of salmon habitat in Russian Creek, Dumbbell Lake,
and the lake’s tributary streams. Technical parameters for proposed 125 kW projects at the four
Knutson Valley resources are summarized in Table 4-1.
Table 4-1: Technical Parameters of Potential Hydropower Developments near Pedro Bay
Parameter Knutson Creek
Main Knutson R1 Knutson L1 Knutson R2
Intake Elevation (ft) 400 500 750 800
Gross Head (ft) 200 350 500 350
Net Head (ft) 169 330 443 403
Penstock Length (ft)
and diameter (inches)
4,700’ of
20” pipe
3,400’ of
16” pipe
4,800’ of
14” pipe
3,500’ of
16” pipe
Design Flow (cfs) 14 6.6 4.7 6.5
Installed Capacity (kW) 125 kW 125 kW 125 kW 125 kW
Plant Capacity Factor 97.5% 72% 66% 79%
Minimum Average Annual
Output (kW) 100 kW 20 kW 10 kW 30 kW
Diesel Load Displaced (kWh)
Percent of Annual Diesel Load
278,000
100%
258,000
93%
245,000
88%
267,000
96%
Annual Excess Energy (kWh) 762,000 510,000 466,000 563,000
Transmission Length (mi) 1.6 1.2 1.8 3.9
Estimated Installed Cost 1 $2,200,000 $2,000,000 $2,300,000 $2,500,000
Estimated BCR with no revenue
from excess energy 1 0.9 0.9 0.8 0.8
Estimated BCR with revenue
from 90% of excess energy 1 1.3 1.0 0.8 1.0
Note 1: BCR means benefit-cost ratio. See section 5 for cost and financial estimates.
Knutson Creek has the best energy generation potential of these resources. This is because this
is the largest creek of the four, and so it has the highest plant capacity factor of the four projects.
Estimated installed costs and estimated benefit-cost ratios (BCRs) were calculated for the
projects. Assumptions used to create these estimates are discussed in section 5.0. Given the
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Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT 17
level of detail and limited information used to develop the cost estimates, the four projects have
fairly similar BCRs. Knutson Creek has the highest BCR, and Knutson tributary R1 is second
highest. Knutson tributaries L1 and R2 are lower, although closer review of these projects could
produce a BCR greater than one.
This findings are consistent with the following considerations:
1. Knutson Creek has the highest plant capacity factor. This means that all else held equal,
the plant produces more energy for the village than the other options.
2. Knutson R1 is closest to Pedro Bay and has the shortest penstock. This reduces the costs
of transmission lines and penstock for this project.
3. Knutson L1 and R2 are farthest from Pedro Bay. These projects incur higher costs for
access trails and power line extensions.
4. Knutson R2 has the largest basin of the three tributary resources, and also has the
highest plant capacity factor of the three. This helps to increases its BCR above that of
L1, but does not overcome the additional costs of access and transmission to be more
cost effective than R1.
4.1.2 Installed Capacity
Section 4.1.1 considers 125 kW projects. Because many of the costs of small hydro projects are
largely independent of their installed capacity, larger projects tend to be more cost effective if
the utility can sell all of the extra energy. In Pedro Bay, it is likely that space and water heating
applications, as well as a general increase in electricity usage, could absorb the extra energy
from a larger hydroelectric plant if the energy was affordably priced.
A 200 kW project was considered at Knutson Creek. The two different Knutson Creek projects
are compared in Table 4-2.
The estimated BCRs for both Knutson Creek projects assume that 316,000 kWh of excess energy
from the hydro projects is directed to the school to replace waste heat from the diesel power
plant at no cost to the school. 5 The agreement between the LPSD and PBVC regarding power
plant waste heat should be reviewed to determine how the loss of waste heat from the power
plant would be addressed.
5 316,000 kWh of energy is based on the cited savings of 11,000 gallons of avoided fuel achieved by the
waste heat system. This is converted to kWh using an assumed fuel heat content of 140,000 btu/gallon, oil
fired HVAC system efficiency of 70%, and electric HVAC system efficiency of 100%.
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT 18
Table 4-2: Comparison of 125 kW and 200 kW Developments at Knutson Creek
Parameter Knutson Creek Main
125 kW
Knutson Creek Main
200 kW
Intake Elevation (ft) 400 400
Gross Head (ft) 200 200
Net Head (ft) 169 171
Penstock Length (ft)
and diameter (inches)
4,700’ of
20” pipe
4,700’ of
24” pipe
Design Flow (cfs) 14 22
Installed Capacity (kW) 125 kW 200 kW
Plant Capacity Factor 97.5% 94%
Minimum Average Annual Output (kW) 100 kW 125 kW
Diesel Load Displaced (kWh)
Percent of annual Diesel Load
278,000
100%
278,000
100%
Annual Excess Energy (kWh) 762,000 1,390,000
Transmission Length (mi) 1.6 1.6
Estimated Installed Cost $2,200,000 $2,500,000
Estimated Benefit-Cost Ratio Range 1 0.9 – 1.3 0.8 – 1.7
Note 1: Range of BCRs is with and without revenues from sale of excess hydro energy.
4.2 RECOMMENDED PROJECT
A project on the main-stem of Knutson Creek is recommended. This project offers the most
cost-effective energy for the community, and would enable the community to turn off its diesel
generators for nearly all of the year. At 125 kW, the project offers a significant amount of excess
electrical energy for the community, although about half of this excess energy would be needed
to replace the diesel plant waste heat that is currently used to heat the school. A 200 kW project
on Knutson Creek would still meet all of the community’s existing electrical needs, heat the
school, and still provide a significant amount of excess energy for the village that could be used
for space heating and other applications.
A project on Knutson tributary R1 also has an estimated BCR greater than 1, and should be
considered in the event that the Knutson Creek project is not feasible. Projects on tributaries L1
and R2 would only warrant further study if Knutson Creek and R1 are not feasible.
4.3 ANNUAL ENERGY PRODUCTION
Pedro Bay’s annual electrical energy generation has varied from 203,000 to 293,000 kWh in
recent years. Average annual generation from 2005 to 2008 was about 278,000 kWh. Detailed
load data is not available, but review of daily plant logs indicate the annual system peak
demand is likely in the range of 60 to 70 kW.
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT 19
The utility uses an average of about 21,400 gallons of fuel annually for power generation. At the
2006 – 2008 average fuel cost of $4.20 per gallon, the utility's fuel expense is $88,800 annually.
4.4 CONCEPTUAL SYSTEM DESIGN
The main stem Knutson Creek project would include the following elements:
4.4.1 Project Access
An access trail would need to be built from the vicinity of the gravel pit and airport up Knutson
Valley to the powerhouse site and continuing up to the intake site. Conditions for trail or road
construction to the powerhouse site are favorable. Surficial soils are generally granular and can
be shaped into a road or trail with modest effort. The terrain is not steep or rugged. The trail
route may need to avoid some areas near Knutson Creek that are prone to flooding or washout.
Conditions for construction of the trail from the powerhouse to the intake also appear favorable,
although the trail may encounter some areas of shallow or exposed bedrock. The terrain in this
area is also steeper and more rugged. Conventional construction methods using earth-moving
equipment should be appropriate for trail construction.
4.4.2 Intake
The intake structures needs to capture all of low flows (14 to 30 cfs), and still function reliably
during the frequent periods of significantly higher flow (100s of cfs). It also needs to function
and survive flood events when Knutson Creek is moving 1,000s of cfs, boulders, trees, and other
debris.
This intake structure may be a low weir or sill built across Knutson Creek. Exposed bedrock is
present in the creek in the intake vicinity - construction would be simplified if a suitable area
with exposed bedrock can be used. The intake structure would direct low flows through an
intake grill where the water would be conveyed to a box on the edge of the creek where it
would be processed to remove sand and organic material (leaves, twigs, etc) that could clog the
turbine. This debris would be flushed back out to the creek.
Design of this intake structure will need to combine reliable function and robust construction
with affordability and constructability. Construction in the early spring may be necessary to
take advantage of pre-breakup low flows.
4.4.3 Penstock
The penstock is a large pipe that conveys clean water from the intake down to the powerhouse.
The penstock would be about 4,700 feet long and 20 or more inches in diameter, depending on
the installed project capacity. The pipe would likely be buried along the access trail between
the powerhouse and intake. The pipe could be installed on-grade in areas with shallow
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT 20
bedrock. Pipe material will depend on a number of factors, including geotechnical conditions,
construction methods, and cost. Common pipe materials would include high-density
polyethylene (HDPE), PVC, ductile iron, or steel.
4.4.4 Powerhouse
The powerhouse is a small building that houses the water turbine, electrical generator, electrical
switchgear, and control equipment. Other equipment for project maintenance can also be
located at the powerhouse. The powerhouse for this project would likely be a wood or metal
framed building. The size of the building would depend on the project capacity, but would be
about 20 feet by 20 feet.
The project would use a cross-flow turbine driving a 480V single phase synchronous generator
via a belt-drive speed increaser. Cross-flow turbines generally have a fairly flat efficiency curve
from 50 to 100% of rated output. Their efficiency drops steeply below 50%, and their minimum
output is about 25% of rated output. At Knutson Creek, there is likely adequate water even
during periods of low flow to keep a turbine running at around 50% of rated output.
The synchronous generator would enable the hydro to run independently of the diesel power
plant or in parallel with the diesel power plant. A transformer would be located at the power
house to step up voltage from 480 V to 7200 V for transmission to Pedro Bay.
4.4.5 Power Line
The power line would run from the hydro powerhouse back to the existing utility distribution
system. The closest electrical cabinet is at the airport apron on the south side of the runway,
about 8,400 feet from the powerhouse location.
Because Pedro Bay’s electrical system is 7.2 kV single phase, a single cable with neutral
conductor can be installed to the power house. This can be a single buried cable or two
overhead wires on poles. Site conditions appear conducive to either construction method.
Electricity would also be run from the powerhouse up to the intake site to power flush gates,
sensors and other apparatus to keep the intake operating. This would likely be a single 480 volt
circuit.
4.4.6 Controls
A communications cable would be run from the powerhouse to the intake. This control cable is
necessary to control the intake systems and also to control the hydro project in general. This
cable could also be used for communications and security purposes.
Another control cable would need to run between the hydro and diesel powerhouses to
coordinate operations. This cable may be able to utilize existing communications in the town,
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT 21
or a dedicated cable can be installed. If a dedicated cable is used, it would be approximately
16,000 feet long. A cable that patches into existing communications circuits would need to be
about 8,400 feet long.
4.5 CONCEPTUAL INTEGRATION DESIGN
The hydro project would be interconnected with the distribution system with a fused
disconnect switch. This would provide protection between the systems, and a means of
isolating the systems when necessary.
The diesel power plant switchgear/controls would be upgraded to function with the hydro
project. The controller would dispatch the hydro first, and then would automatically turn on
diesel generators when the system load was within a certain threshold of the hydro’s available
output.
With the recommended hydro project and existing system demand, the diesel generators would
run very infrequently – for a few days a year at most.
Pedro Bay could use excess energy from the hydro either on dedicated discretionary circuits or
for uncontrolled applications. Dedicated discretionary circuits would only allow energy usage
when it was available – during periods of low flow, these circuits would be disabled to avoid
having to turn on the diesel engines. These circuits would typically be for a few large loads,
such as heating for the school and community building.
Uncontrolled loads would come on at any time, and would tend to increase the system's peak
demand. If the increased peak demand is large enough, the diesel plant would be run more
often. The best approach for Pedro Bay is a matter of economics that would be addressed
during the feasibility or design phase of the project.
4.6 REMAINING TECHNICAL CONSIDERATIONS
4.6.1 Hydrology
Existing limited hydrology data indicates that the recommended hydro project(s) on Knutson
Creek and Knutson tributary R1 are favorable. For Knutson Creek, more data or more extensive
statistical analysis of existing data is needed to confirm these findings. For tributary R1, stream
gauging data is necessary.
If further analysis of existing data indicates that additional data is needed at Knutson Creek,
installing stream gauges in Knutson Creek and Knutson tributary R1 is recommended. The
critical season for gauging Knutson Creek is through the winter months to capture seasonal low
flows. Low flows during the summer months are relatively less important because they are
caused by dry spells, and tend to be of shorter duration.
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT 22
Depending on available gauging sites, it may be appropriate to remove the Knutson Creek
gauging hardware during the summer months to reduce the likelihood that the hardware is
damaged or destroyed by high flows.
Concurrent gauging of Knutson tributary R1 is recommended so that the development schedule
for hydropower is not unduly delayed in the event that a project on Knutson Creek is not
feasible. Because the design flow on R1 is a greater fraction of the average flow for this creek,
year-round gauging is recommended.
One of the first tasks in the feasibility phase of the project should be to evaluate existing data to
determine if additional gauging is warranted at Knutson Creek. If so, gauges should be
installed as soon as possible to start collecting hydrology data for these resources.
4.6.2 Installed Capacity
This reconnaissance study considered 125 kW and 200 kW projects at Knutson Creek.
Assuming that all of the excess energy is purchased and used by the community, the larger
project has a higher benefit-cost ratio. The feasibility study needs to determine the optimum
installed capacity for this resource and Pedro Bay. This decision will be influenced by:
Ø Community demand. A larger hydro project is justified only if the community can pay
for and use all or most of the energy the project produces.
Ø Resource availability. Knutson Creek has plenty of water to operate larger projects.
Ø Project cost. Many costs associated with a small hydro project are entirely or mostly
independent of installed capacity. Project capacity can therefore be increased with a
comparatively modest increase in construction or maintenance costs.
4.6.3 Existing Electric System Constraints
The capacity of the existing electric system should be assessed to verify that it is adequate to
receive all power from the hydroelectric project. This is more of an issue for larger projects.
Some distribution system upgrades may be necessary depending on the size of the existing
conductors and transformers in the existing system.
4.6.4 Financing
PBVC needs to consider how it would pay for a hydro project. The basic financing options are
grant financing, capital financing, debt financing, or a combination of these.
Ø There are a variety of federal and state grant programs that could provide complete or
partial funding for project construction. Grants generally will only pay for pre-
construction and construction expenses – they generally do not pay for post-
construction operating costs.
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT 23
Ø Capital financing would be possible if PBVC has the funds necessary to build the project
out-of-pocket. If PBVC did have construction funds, it would likely require a return on
its investment, which would affect the revenue structure and electric rates for the utility.
Ø Debt financing could be achieved through either private sector or public sector
financing. The project's capital cost is small for private bonding, although there are
some entities that handle micro bonds of this size. There are state or federal financing
programs such as the state's Power Project Fund that could be used for project financing.
Some of these programs offer below-market interest rates to help support the project.
There are also a variety of government loan guarantee programs that can help reduce
the interest rates for private-sector financing.
4.6.5 Geotechnical / Topographic Considerations
A topographic and geotechnical site survey is necessary to determine the hydraulic head on the
resource, specific intake location, penstock alignment, powerhouse site, and access route.
Topographic or geotechnical conditions at these sites may call for different design approaches
than outlined in this reconnaissance study.
4.6.6 Permits
ADFG should be consulted about the project to determine what will be required to obtain a fish
habitat permit for the project. ADFG’s permitting requirements may affect project feasibility.
There may be other unknown permitting issues, such as the presence of significant
archeological resources in the project footprint, that would affect project feasibility. Resource
agencies should be consulted in an effort to identify any such issues.
4.6.7 Feasibility Study
Once the additional data described above is collected, a more detailed study of project
feasibility is necessary. The feasibility study would focus on technical and economic issues to
confirm the project is feasible.
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT 24
5.0 ECONOMIC ANALYSIS
Table 5-1 summarizes economic data for the recommended hydro projects. More detailed data
and explanation is presented in the following sections.
Table 5-1: Summary of Economic Data for Recommended Hydroelectric Projects
Item Knutson Creek
(200 kW)
Knutson Creek
(125 kW)
Tributary R1
(125 kW)
Pre-Construction Activities (Feasibility, Design,
Permitting) $195,000 $195,000 $195,000
Direct Construction Cost $1,630,000 $1,450,000 $1,300,000
Project Administration / Management $68,000 $68,000 $64,000
Construction Engineering / Inspections /
Commissioning $68,000 $68,000 $64,000
Contingency $474,000 $362,000 $325,000
Financing $65,000 $57,000 $52,000
Project Installed Cost $2,500,000 $2,200,000 $2,000,000
Annual O, M, R & R Costs / Savings (50 years) $17,000 $17,000 $15,700
Annual Debt Service (30 years) $127,700 $109,800 $101,200
Salvage Value (at 50 years) $0 $0 $0
Present Value of Project Costs $2,940,000 $2,590,000 $2,388,000
Displaced Power Plant Energy (kWh / year) 278,000 278,000 258,500
Displaced Power Plant Fuel (gallons / year) 21,400 21,400 19,900
Annual Value of Displaced Fuel ($ / year) $89,800 $89,800 $83,500
Present Value of Project Benefits (50 years) $2,310,000 $2,310,000 $2,149,000
Benefit Cost Ratio (no excess energy benefit) 0.8 0.9 0.9
Gross Excess Hydro Energy (kWh / year) 1,310,000 762,000 488,000
Net Metered Excess Hydro Energy (kWh / yr) 1 701,400 276,000 85,400
Displaced Heating Fuel (gallons / year) 2 24,400 9,600 3,000
Annual Value of Displaced Heating Fuel ($ / yr) $102,600 $40,400 $12,500
Present Value of Project Benefits (50 years) $4,950,000 $3,349,000 $2,470,000
Benefit Cost Ratio
(with excess energy benefit) 1.7 1.3 1.0
Note 1: The analysis assumes 90% of excess energy generation is dispatched to community loads. Of
this, 13.7% is consumed by distribution system losses (based on past system performance from
PCE reports). Of the remaining excess energy, up to 315,000 kWh is subtracted for unbilled
energy used by the school to replace waste heat energy.
Note 2: The analysis assumes that heating oil displaced by hydro excess energy was consumed with a
community –wide average efficiency of 70%.
Table 5-2 presents estimated electricity rates for 100% debt-financed and 100% grant-financed
projects. Figures in Table 5-2 have not been adjusted to reflect PCE-subsidized electric rates.
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT 25
Table 5-2: Estimated Electric Rates with Hydro Projects
Item Knutson Creek
(200 kW)
Knutson Creek
(125 kW)
Tributary R1
(125 kW)
Estimated Electric Rate
100% Debt Financed Hydro 1
$0.40 to $0.46
per kWh
$0.50 to $0.79
per kWh
$0.63 to $0.77
per kWh
Estimated Electric Rate
100% Grant Financed Hydro 1
$0.27 to $0.29
per kWh
$0.28 to $0.32
per kWh
$0.30 to $0.32
per kWh
Note 1: Range of rates is with and without revenues from sale of excess hydro energy.
5.1 ANNUAL PROJECT COSTS
5.1.1 Operation and Maintenance
Total non-fuel O&M costs for PBEU have averaged about $42,000 annually over the past several
years.6 This annual expense includes activities such as meter reading, customer service,
managing customer accounts, etc. These costs will not change if the means of energy generation
changes from diesel to hydroelectric or a combination.
This annual expense also includes the costs of lube oils, filters, and other consumables for the
diesel generators, maintenance labor, and similar costs that are directly tied to the running time
of the diesel engines. Nearly all of these costs will be avoided with any of the recommended
hydroelectric projects.
Because the diesels would effectively become a back up power supply, they would be run much
less often with the hydroelectric project in service. They would therefore use fewer
consumables and would require less frequent overhauls. These values are assumed to be worth
15% of total annual non-fuel expenses, or $6,300 annually.
The hydroelectric project will have operation and maintenance costs. Based on experience with
similar projects, annual O&M costs are estimated to be $11,000 annually. This includes
additional labor costs for monitoring and maintaining the hydro as well as direct expenses for
parts and consumables.
5.1.2 Repair and Replacement
Most of the hydroelectric project systems and components have a very long useful life. The
intake, penstock, powerhouse, switchgear, turbine/generator, and power line all have useful
lives of at least 30 years. Some portions of the project will require periodic repair or
replacement. Some minor components, such as the hydraulic pumps, control sensors, and
similar devices, are assumed to have a useful life of five years. The water turbine would need
6 State of Alaska Power Cost Equalization Program Annual Report, Alaska Energy Authority, 2002 – 2008.
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT 26
an overhaul at about 15 to 25 years. The average annual expense for repair and replacement is
estimated at $7,800.
5.1.3 Property
The recommended hydroelectric project is located on village corporation land. The cost of
access to this property will depend on the agreement that is reached between PBEU and PBC.
For reconnaissance level financial analysis, the property cost is assumed to be $4,500 annually.
5.1.4 Taxes
No tax liability is considered.
5.1.5 Insurance
It is assumed that the PBEU’s existing insurance policies would be adequate for the
hydroelectric project. No annual cost is allocated for insurance.
5.1.6 Financing
The costs of financing will depend on the type of financing used for the project. Financing
options vary from government grants or loans to commercial financing options such as
bonding.
Commercial finance for the project is assumed to consist of a 30-year bond at a nominal interest
rate of 6%. Adjusted for inflation (assumed at 3% average over 30 years), this is a real interest
rate of approximately 3%. In addition, the cost of preparing and issuing the bond adds about
3% to the cost of the project (for items such as application fees, loan guarantee fees, origination
fees, etc).
5.2 PROJECT REVENUES AND SAVINGS
5.2.1 Direct Fuel Displacement
The hydro project will displace all or nearly all of the fuel currently consumed by the diesel
power plant. Fuel savings are based on the diesel plant’s existing generation efficiency of 13.0
kWh per gallon, and 2006 – 2008 average fuel price of $4.20 per gallon.
5.2.2 Excess Energy
In addition to the diesel electric generation that the hydro displaces, it also generates a
significant amount of excess energy that is available to the community. For economic analysis
purposes, 10% of this gross excess energy is assumed to be consumed by the hydro load
governor system, and 90% is assumed to be made available to system loads such as space
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT 27
heating and water heating uses. Of this 90%, 13.7% is assumed to be consumed by losses on
PBEU’s distribution system (based on existing system efficiency). The balance (77.7% of gross
excess energy generation) can be metered to PBEU’s accounts.
All of this excess energy is assumed to be directed to space and water heating applications,
displacing heating oil that is consumed with an average efficiency of 70%. Because the school
currently receives waste heat from the power plant, worth 11,000 gallons of heating oil
annually, an equivalent amount of excess hydro energy, 315,800 kWh, is allocated to the school
at no cost in all economic analyses. 7 How the school’s energy needs are met and the impact
that has on the hydro’s revenues will depend on the contractual relationship between PBEU and
LPSD.
5.2.3 Environmental Attributes
As a small, low-impact, run-of-river hydroelectric project, this hydro project would have the
ability to market its environmental attributes nation-wide. The market for environmental
attributes is still developing, and as a result is subject to considerable uncertainty. There is
federal and state legislation pending that could influence this market, transforming it from the
existing patchwork of state compliance markets and national and regional voluntary markets
into a more uniform and regulated national market. A reasonable range for the value of the
environmental attributes from this project is $0.005 to 0.020 per kWh on the voluntary market.
Pedro Bay has the potential to market its unique Alaska setting to command a premium for its
environmental attributes. For the economic analysis, no revenue from sale of environmental
attributes is assumed.
5.2.4 Indirect and Non-Monetary Benefits
The recommended hydroelectric project offers significant indirect and non-monetary benefits in
addition to direct economic benefits. These other benefits include:
Ø Reduced air pollution (NOx, SOx, particulates, and hydrocarbons) due to decreased
operation of the diesel power plant
Ø Reduced noise when the diesel plant is turned off.
Ø Reduced risk of oil spills due to decreased throughput and handling of fuel.
Ø More stable energy prices. With the hydro, PBEU’s electricity rates will be largely
insulated from increasingly volatile world oil prices.
Ø Secondary benefits arising from the availability of plentiful hydropower with a stable
price. This will increase the affordability of living and doing business in Pedro Bay and
7 AEE estimated that the waste heat system would displace up to 11,000 gallons of heating oil
annually. Pedro Bay Energy Upgrades Concept Design Report, AEE, 2003.
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT 28
will increase the long-term viability of the community. Secondary benefits could
include an increase in the population of school-age children, ensuring that school
enrollment exceeds district and state thresholds for state funding year-to-year.
Ø Economic multipliers due to the fact that a greater percentage of the utility's revenues
will be retained in the local community for labor instead of paying external entities such
as fuel suppliers.
Ø Local training and experience with small hydroelectric projects. To the extent that locals
choose to be involved in construction, maintenance, and operation of the hydro, they
will learn a unique set of skills. These skills will become increasingly useful as Alaska
continues to develop local hydropower resources.
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT 29
6.0 PERMITS
6.1 FEDERAL PERMITS
6.1.1 FERC
The Federal Energy Regulatory Commission has jurisdiction over hydropower projects that
meet certain criteria. The recommended project does not meet any of these criteria, so FERC
does not have jurisdiction. To formalize this finding, a Declaration of Intent would be filed with
FERC. FERC will review the Declaration of Intent and solicit public comments, and then issue a
ruling on the Declaration. It is probable that FERC would concur that the project is non-
jurisdictional.
6.1.2 U.S. Army Corps of Engineers Permits
The project intake and tailrace will be located within wetlands, therefore a wetlands permit
from the COE will be required. Other project features may also be located in wetlands. The
project is likely eligible for a Nationwide Permit #17 for small hydroelectric development.
6.1.3 U.S. Environmental Protection Agency
A stormwater pollution prevention plan (SWPPP) will be required for the project.
6.1.4 Federal Aviation Administration
The project is located within five miles of Pedro Bay’s airport, so consultation with FAA and/or
the Alaska Department of Transportation is needed. The project will not have any features
likely to present a hazard to aviation.
6.2 STATE OF ALASKA PERMITS
6.2.1 Department of Natural Resources Permits
6.2.1.1 Coastal Zone Consistency Review
The recommended project is located within the Lake and Peninsula Borough Coastal Zone. The
project will therefore have to be reviewed by ADNR’s Division of Coastal and Ocean
Management for consistency with the area’s coastal management plan.
6.2.1.2 Land Authorizations
The recommended project would not occupy state lands.
Pedro Bay Village Council
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OCTOBER 2009 – FINAL REPORT 30
6.2.1.3 Tidelands Permits
Not applicable.
6.2.1.4 Material Sale Agreement
Not applicable.
6.2.1.5 Water Use Permit / Water Rights
The project would need to obtain water rights from the ADNR.
6.2.2 Department of Fish and Game Permits
6.2.2.1 Fish Habitat Permit
The project would need to obtain a fish habitat permit or a finding that a permit is not required
from the ADFG.
6.2.3 Department of Transportation Permits
Not applicable.
6.2.4 Department of Environmental Conservation Permits
6.2.4.1 DEC Wastewater or Potable Water Permits
Not applicable.
6.2.4.2 Solid Waste Disposal Permit
It may be desirable to dispose of bulky inert construction wastes from the project in an on-site
monofill. This would require an ADEC monofill permit and approval of the land owner.
6.2.4.3 Air Quality Permit& Bulk Fuel Permit
Not applicable.
6.3 LOCAL PERMITS
The project is located within the Lake and Peninsula Borough, and will have to comply with the
Borough’s permitting processes.
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT 31
7.0 ENVIRONMENTAL CONSIDERATIONS
7.1 THREATENED AND ENDANGERED SPECIES
The U.S. Fish and Wildlife Service’s on-line consultation guide indicates that there are no
species listed as threatened or endangered within the vicinity of the project. 8
7.2 FISHERIES AND WILDLIFE
Development of the recommended project has the potential to affect fisheries and wildlife
resources. Significant effects to wildlife are considered very unlikely.
The ADFG's Atlas of Waters Important for the Spawning, Rearing or Migration of Anadromous
Fishes indicates that the lower reaches of Knutson Creek below the project are spawning habitat
for sockeye salmon and also habitat for arctic char. These habitat areas extend upstream
approximately to the proposed powerhouse location.
Because the recommended project is a run-of-river system, it does not change the flow below
the project. Because the project is located above fish habitat, it is considered unlikely to
adversely affect fish habitat.
It is recommended that ADFG be consulted regarding the project to determine what ADFG will
require to issue a fish habitat permit for the project.
7.3 WATER AND AIR QUALITY
The project would not significantly impact water or air quality.
7.4 WETLAND AND PROTECTED AREAS
The project will require filling wetlands areas, such as for portions of the diversion structure
located in the creek. Other wetlands areas may be affected by the project as well.
7.5 ARCHAEOLOGICAL AND HISTORICAL RESOURCES
None known. The state historical preservation office should be consulted to see if any historical
or cultural resources are present in the project area.
7.6 LAND DEVELOPMENT CONSIDERATIONS
None.
8 http://alaska.fws.gov/fisheries/endangered/pdf/consultation_guide/70_consult_guide_map_11x17.pdf
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT 32
7.7 TELECOMMUNICATIONS AND AVIATION
The project will not affect telecommunications. The project will not affect aviation.
7.8 VISUAL AND AESTHETICS RESOURCES
The project would primarily be visible from the air or alpine vantage points along Knutson
Valley. The project would not be significantly visible from land or from Iliamna Lake.
7.9 MITIGATION MEASURES
No impacts warranting mitigation are known at this time.
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT 33
8.0 FINDINGS AND RECOMMENDATIONS
8.1 FINDINGS
This reconnaissance study has identified hydropower resources on Knutson Creek and Knutson
tributary R1 near Pedro Bay that appear feasible. Development of either resource would supply
most of the village’s existing electrical demand and also provide significant additional energy.
Other hydropower resources near Pedro Bay also have promise, but are considered inferior to
projects on Knutson Creek and Knutson tributary R1, based on current information. In the
event neither of these projects is feasible, the other projects should be investigated.
Existing hydrology information should be analyzed to determine if additional hydrology data is
needed. If additional data is needed, stream gauges should be installed in Knutson Creek
and/or Knutson tributary R1 as soon as possible to begin collecting discharge data for these
resources. Collecting data in both resources would allow PBVC to avoid delaying hydro
development in the event that one of the resources is not feasible.
Obtaining permits for the recommended projects should be relatively straightforward. ADFG
should be consulted to discuss the salmon habitat in Knutson Creek and determine what
information they will require to issue a fish habitat permit for the project(s).
Additional field investigations are needed to review topography and geotechnical conditions
along the project corridors. The intake sites and upper penstock routes are of particular
importance.
Once additional information is collected, a feasibility study should be completed to confirm the
preliminary findings and recommendations made in this report.
8.2 DEVELOPMENT PLAN & SCHEDULE
The major steps to advance the recommended hydro projects are:
1. Determine if additional stream gauging is necessary.
2. Conduct additional field investigations for both resources.
3. Consult with resource agencies on key permits required for the projects.
4. Complete a feasibility study of the projects – identify the preferred project.
5. Apply for permits required for the preferred project.
6. Complete engineering designs.
7. Secure construction funding.
8. Construction.
Based on current information, either of the projects can be ready for construction in 2012. A
project schedule is presented in Figure 8-1.
Pedro Bay Village Council
Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
OCTOBER 2009 – FINAL REPORT 34
Figure 8-1: Project Development Schedule
2009 2010 2011 2012
ACTIVITY Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
Feasibility Study Activities
Hydrology
Add'l Field Investigations
Agency Consultations
Feasibility Study and Report
Prepare and File Permit Applications
FERC DOI
COE Wetlands Permit
ADNR Coastal Zone Consistency Review
PBC Property Agreement
ADNR Water Rights
ADFG Fish Habitat Permit
Process / Recieve Permit Authorizations
FERC DOI
COE Wetlands Permit
ADNR Coastal Zone Consistency Review
PBC Property Agreement
ADNR Water Rights
ADFG Fish Habitat Permit
Project Design
Conceptual Design
100% Design
Construction Plan
Arrange Financing
Construction
Post Construction Activities
As-Built Survey
Finalize Property Documents