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L ETTER R EPORT
140120-ELFINHYDROCONCEPTUALDESIGNREPORT.DOC
DATE: January 20, 2014
TO: Jane Button, ECUC Project Manager
FROM: Joel Groves, PE Polarconsult Manager
SUBJECT: Elfin Cove Hydroelectric Project Conceptual Design and Development Plan
ATTACHMENTS: Interim Hydrology Report, Polarconsult, December 20, 2013
1. INTRODUCTION AND SUMMARY OF FINDINGS
As a precursor to commencing design and permitting of the Crooked Creek and Jim’s Lake
Hydroelectric Project, the Alaska Energy Authority (AEA) has requested that the Elfin Cove
Utility Commission (ECUC) complete an updated sizing analysis to determine the size and final
configuration of the proposed project. The AEA specifically requested that the sizing analysis
consider recommendations of previous completed engineering reports and current hydrology
information. In addition to these reference materials, Polarconsult has also analyzed current
utility load data for this analysis. AEA also requested preliminary cost estimates, economic
analysis, conceptual design, and development plan for the recommended project configuration.
This letter report presents the updated sizing analysis, conceptual design narrative, cost
estimate, economic analysis, and development plan for ECUC and AEA’s review. Applicable
supporting information and documentation is included with or attached to this report.
Conceptual design drawings for the recommended project will be provided to ECUC separately.
Based on the analysis summarized in this letter report, the recommended project configuration
is very similar to previously proposed configurations. The recommended installed capacity is
140 kW, consisting of a 35 kW run‐of‐river upper system between Crooked Creek and Jim’s
Lake, and a 105 kW storage lower system between Jim’s Lake and tidewater at Little Sandy
Beach. Current utility load and hydrology data both support a smaller project capacity than
recommended by the 2011 Feasibility Study. The recommended project configuration is
estimated to displace 89% of the diesel fuel consumed by the electric utility annually.
A siphon intake at Jim’s Lake will allow the lower system to regulate flows from Jim’s Lake,
drawing the lake down a maximum of eight feet below its natural level. No dam at the lake
outlet is proposed. This project configuration is understood to be eligible for an exemption
from FERC licensing requirements.1
2. BACKGROUND
Polarconsult completed reconnaissance and feasibility studies for the hydro project in June
2010 and June 2011, respectively. Mead & Hunt completed an independent engineer’s
evaluation of the project configuration recommended in the 2011 feasibility study in October
2012.2 The general project configurations are summarized in Table 1.
1 See FERC DI 11‐11‐000, Issued July 11, 2011.
2 Hydroelectric Reconnaissance Study Final Report; Elfin Cove, Alaska. Polarconsult Alaska, Inc. June 2010.
Crooked Creek and Jim’s Lake Hydroelectric Feasibility Study Final Report. Polarconsult Alaska, Inc. June 2011.
Elfin Cove Hydroelectric Project Conceptual Design and Development Plan
Letter Report Polarconsult Alaska, Inc.
January 20, 2014 Page 2 of 11
Table 1: Previously and Currently Proposed Hydro Project Configurations
Source Installed
Capacity
Total Annual
Hydro Generation
Estimated
Installed Cost
Percent of ECUC
Load Met by Hydro
2010 Recon. Study 200 kW 716,000 kWh $2.5 – 3.6M 97%
2011 Feas. Study 160 kW 672,700 kWh $1.85M 99%
2012 Independent
Evaluation 125‐150 kW ‐ ‐ ‐
2014 Recommended
Configuration 140 kW 613,800 kWh $3.38M 89%
3. METHODOLOGY
Determining the ‘optimal’ installed capacity is one of the most subjective and challenging
engineering tasks associated with developing a hydroelectric project for a micro‐grid such as
ECUC. The hydro project will be a 50+ year asset. Undersizing the project sacrifices an
opportunity to support future growth of the community at very modest incremental capital
expense. Likewise, oversizing the project results in unnecessary capital expense with no benefit
to the community, and can also burden the community with increased operation and
maintenance (O&M) expenses over the life of the project.
For this updated analysis, Polarconsult analyzed several project alternatives using similar
methodology to that used for the 2011 Feasibility Study. Updated utility load data and
hydrology information, described in this letter report and attachments, was used for the
current analysis.
4. UPDATED PROJECT DATA
4.1 Hydrology
Stream gauging stations are maintained at the Crooked Creek diversion site and Jim’s Lake
outlet. These gauging stations are described in Appendix C of the 2011 Feasibility Study.
Polarconsult has reviewed additional hydrology data collected since 2011.3 Analysis of all
available hydrology data indicate flows in Crooked Creek and Jim’s Lake are approximately 80%
of the flows that were estimated in 2011. The analysis presented in this memo is based on
current hydrology data.
4.2 ECUC System Electric Load
The 2011 Feasibility Study was based on annual utility load of 359,000 kWh.4 Subsequent utility
load has trended lower. Utility load was approximately 8% lower (~330,000 kWh) in 2009 and
2010, and approximately 16% lower (~300,000 kWh) in 2011 and 2012. 2013 load is estimated
to be approximately 25% lower, at 275,000 kWh. Table 2 and Figure 1 summarize recent
information for the electric utility.
Independent Engineer’s Evaluation Final Report. Hydropower Feasibility Development for the Community of Elfin
Cove, Alaska. Mead & Hunt. October 2012.
3 Interim Hydrology Report, Polarconsult Alaska, Inc., December 20, 2013 (attached).
4 Feasibility Study Final Report, Table 4‐1.
Elfin Cove Hydroelectric Project Conceptual Design and Development Plan
Letter Report Polarconsult Alaska, Inc.
January 20, 2014 Page 3 of 11
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Jan‐03 Jan‐04 Jan‐05 Jan‐06 Jan‐07 Jan‐08 Jan‐09 Jan‐10 Jan‐11 Jan‐12 Jan‐13Average kWAverage Monthly Power Generation
ECUC load varies seasonally, with low demand in the winter months (October to April) and high
demand in the summer months (May to September). Both winter and summer loads have
decreased since the 2011 study. Average winter load was 20 – 30 kW from 2005 through 2009,
but decreased to 15 – 20 kW from 2010 to 2012. Average summer load has seen a similar
decrease, from 70 – 90 kW from 2005 through 2009, 70 – 80 kW from 2010 to 2012, and 60 –
70 kW in 2013.
These decreasing load trends are attributed to the increasing cost of electricity in Elfin Cove and
resulting ratepayer efforts to increase efficiency and control their utility expenses. Electricity
rates over this same time period have nearly doubled from $0.42 per kWh in 2005 to $0.80 per
kWh in 2012. Even though utility load and fuel use have decreased over time, total fuel costs
have remained constant at approximately $120,000 per year since 2008.
This analysis uses an annual utility load of 300,000 kWh, with 110,000 occurring during the
winter season (September 15 through May 15), and 190,000 kWh during the summer season
(May 15 through September 15).
Figure 1: Average Monthly ECUC System Load 5
5 2003 to 2011 data are from 2011 Feasibility Study. 2011 to 2013 data are provided by ECUC.
Elfin Cove Hydroelectric Project Conceptual Design and Development Plan Letter Report Polarconsult Alaska, Inc. January 20, 2014 Page 4 of 11 Table 2: Recent ECUC Electric Utility Data Data from 2003 to 2010 is compiled from monthly Power Cost Equalization (PCE) program records provided by the AEA. Data from 2011 to 2013 are provided by ECUC. (1) Data for 2003 include July through December. (2) Records from 2007 are incomplete due to power plant replacement project. (3) No station service data are available for March 2006 and April 2007 through November 2008. (4) Records from February 2011 to October 2013 only include total kWh generated, total kWh sales, total fuel consumption, and fuel price. (5) Data for 2013 include January through October. (6) Rates are for “average residential rate for 500 kWh/month consumption”, compiled from annual Statistical Report of the PCE Program, published by the AEA. Each report covers the state fiscal year (July 1 of the preceding year to June 30 of the calendar year). All other data in this table is based on calendar years. ‘–’ denotes data that are not available or not meaningful due to incomplete records. NA Not available. Parameter 2003 (1) 2004 2005 2006 2007 (2) 2008 2009 2010 2011(4) 2012(4) 2013 (4,5) kWh Generated 215,404 387,727 344,557 342,883 235,574 (2) 377,150 339,609 325,810 297,578 301,721 251,134 kWh for Station Service (% of total generation) 12,809 (5.9%) 24,785 (6.4%) 28,421 (8.2%) 24,147 (3) (7.0%) 1,734 (2,3) (‐‐%) 1,544 (3) (‐‐%) 25,045 (7.4%) 32,615 (10.0%) NA NA NA kWh Sold 200,865 318,937 301,614 302,051 295,567 334,177 291,866 259,139 240,990 245,865 206,675 Fuel Price (annual average) $1.84 $2.21 $2.94 $3.64 $3.56 $5.14 $4.62 $3.98 $4.78 $5.02 $5.12 Fuel Used (gallons) 17,583 32,938 31,778 31,161 31,727 30,678 26,413 26,539 25,096 24,685 20,927 Total Fuel Expense $32,380 $72,831 $93,414 $113,477 $112,806 $157,599 $122,068 $105,662 $120,043 $123,990 $107,244 Total Non‐Fuel Expense $24,796 $58,949 $55,867 $28,702 $41,078 $35,406 $32,739 $43,80 NA NA NA Total Utility Expense $57,177 $131,780 $149,281 $142,178 $153,884 $193,005 $154,807 $149,471 NA NA NA Power Cost per kWh $0.28 $0.41 $0.49 $0.47 $0.52 $0.58 $0.53 $0.58 NA NA NA Unsubsidized Electric Rate per kWh (6) $0.25 $0.25 $0.42 $0.51 $0.427 $0.56 $0.523 $0.523 $0.694 $0.80 NA Generation Efficiency (kWh/gal) 12.3 11.8 10.8 11.0 7.4 (2) 12.3 12.9 12.3 11.9 12.2 12.0
Elfin Cove Hydroelectric Project Conceptual Design and Development Plan
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January 20, 2014 Page 5 of 11
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9/15/089/15/099/15/109/15/119/15/129/15/13Daily Utility Demand and Supply (kW)Excess Hydro Available (kW)
Demand Supplied from Diesel (kW)
Demand Supplied from Hydro (kW)
Total System Demand (kW)
Energy Supplied by Hydro
Energy Supplied by Diesels
Current Utility Demand
Excess Energy available from Hydro
Energy Supplied by Diesels
5.0 RECOMMENDED PROJECT CONFIGURATION AND ALTERNATES CONSIDERED
Conceptual design drawings for the recommended project will be provided to ECUC separately.
These conceptual design drawings are based on LiDAR of the project site, field reconnaissance
completed in July 2013, and the conceptual project configuration described in this section.
5.1 Recommended Project Configuration
The recommended hydro project configuration has an upper system between Crooked Creek
and Jim’s Lake with a 5 cfs design flow and estimated 35 kW generating capacity, and a lower
system between Jim’s Lake and tidewater with a 6.5 cfs design flow and estimated 105 kW
generating capacity. The total capacity of this configuration is 140 kW.
ECUC demand and supply with the recommended project, based on 300,000 kWh annual utility
demand and site hydrology data collected from 2008 throgh 2013, is presented in Figure 2.
Generally, the diesel plant operates during longer dry spells in the summer months, when there
is insufficient flow in Crooked Creek to meet utility demand and Jim’s Lake is drawn down. In
years with prolonged snow melt or wetter summers (2010, 2012) the hydro is able to supply
over 98% of annual demand. In drier years, (2009, 2011, 2013) the hydro is able to supply 77 to
82% of annual demand.
Figure 2: ECUC Demand and Supply with Recommended Hydro Project
Elfin Cove Hydroelectric Project Conceptual Design and Development Plan
Letter Report Polarconsult Alaska, Inc.
January 20, 2014 Page 6 of 11
The final installed capacity, which will depend on the water‐to‐wire efficiency of the turbines
and generators that are used, is expected to be in the range of 130 to 150 kW. Technical
aspects of the recommended project are summarized in Table 3, and a more detailed
description of the recommended project configuration follows.
Table 3: Technical Summary of Recommended Project
COMMON PROJECT FEATURES VALUE
Access Trails 12,200 feet
Power Lines 11,500 feet
Communications Lines 14,000 feet
INDIVIDUAL HYDRO SYSTEM FEATURES VALUES
Individual System Parameters Upper System Lower System Total
Basin Area (square miles) 0.56 sq.mi. 0.10 sq.mi. 0.66 sq.mi.
Median Flow (cfs) 2.5 cfs 0.4 NA
Minimum Flow (cfs) 0.2 cfs ~0.04 NA
Plant Design Flow (cfs) 5.0 cfs 6.5 cfs NA
Intake Elevation (ft, MSL) 479 ft 329 ‐ 337 ft NA
Powerhouse Elevation (ft, MSL) 342 ft 24 ft NA
Gross Head (ft) 137 ft 305 ‐ 313 ft NA
Pipeline Length (ft) / Diameter (in) 1,250’ of 12” pipe 2,030’ of 14” pipe NA
Net Head (ft) 124 ft 286 ft NA
Minimum Power Generation (kW) 7 kW 11 kW 7 kW
Installed Capacity (kW) 35 kW 105 kW 140 kW
Dam/Diversion Height (ft) none none NA
Available Storage Volume (ac‐ft) none 32 ac‐ft 32 ac‐ft
Estimated Annual Energy Generation
Total Annual Hydro Energy Generation (kWh) 153,400 460,400 613,800
Gross Excess Energy Available from Hydro (kWh) 347,500
Hydro Output used to Supply ECUC Load (kWh)
(percent of total ECUC load supplied by hydro)
266,300
(89%)
ECUC Load Met by Diesel Powerplant (kWh) 33,700
Total ECUC Load (kWh) 300,000
MSL: Mean sea level NA: Not Applicable.
Access Trails
With the exception of state land within the Elfin Cove town site, all of the project land is within
inventoried roadless areas of the Tongass National Forest. Accordingly, project access will
utilize trails rather than roads, with trail widths minimized to the extent practical.
Primary access for construction and heavy maintenance will be from Small Sandy Beach. A
permanent access trail will be built from the beach up to Jim’s Lake, continuing up to the
Crooked Creek intake site. A short spur trail will lead to the upper powerhouse site on the
shore of Jim’s Lake. This trail network will total approximately 4,200 linear feet. The initial
climb up from the beach will be a bench blasted in rock to an elevation of approximately 100
feet. The remainder of these trails will be at grades of up to 20%, either sidehilling through
mixed forest or traversing peat meadows. Some additional blasting may be required for these
trails depending on depth to rock along the trail route.
Elfin Cove Hydroelectric Project Conceptual Design and Development Plan
Letter Report Polarconsult Alaska, Inc.
January 20, 2014 Page 7 of 11
Routine access for O&M will utilize an ATV trail from Elfin Cove. This trail will start at tidewater
on the west side of the cove and continue approximately 8,100 linear feet to intersect with the
project trail system. Approximately 1,000 linear feet of this trail is on state‐owned land within
the Elfin Cove town site, and the balance crosses National Forest land. There is no developed
trail system at the starting point for this access trail in Elfin Cove. Because Elfin Cove’s existing
trails are not suitable for ATV traffic, it is recommended that an ATV shed be installed above
tidewater at this trail head. Utility personnel would walk or skiff to the trail head, and then
take an ATV to the project site to perform O&M duties.
Based on review of site topography, alternate trail alignments near Elfin Cove that cross private
lands may be less costly to build than the proposed route. These land owners will be consulted
during the permitting process to see if they are amenable to granting easements for an access
trail.
Power, Communications, and Controls
Power generated at the two hydro powerhouses will be stepped up to 7.2 / 14.4 kV and
transmitted to Elfin Cove via a buried armored cable. The cable will be installed along the
access trail route. The power cable will connect to the existing utility distribution system near
the start of the access trail in Elfin Cove.
A dedicated communications cable will also be buried in the access trail to connect the two
hydro powerhouses to the diesel powerhouse. The final communications connection within
Elfin Cove can be made by either leasing capacity on the local communication network (if
available) or installing a submarine cable under the Cove from the trailhead to the diesel
powerhouse.
Controls for the coordination of the two hydro powerhouses and the diesel powerhouse will be
located in the diesel powerhouse. These controls will support interrogation of the two hydro
powerhouses from the diesel powerhouse to facilitate operations.
Upper System
The upper system intake will consist of an inclined plate screen located at a natural cascade on
Crooked Creek at an elevation of 479 feet. Water will flow over the screen, with up to five cfs
flowing through the screen and into a collection gallery. Water will flow from the gallery into
the penstock.
The penstock will be a 12‐inch diameter SDR 26 HDPE pipe approximately 1,250 feet long. The
pipe will be buried in the access trail from the intake to the powerhouse. Control wiring will be
buried parallel to the penstock to a head level probe at the intake.
The upper powerhouse will be an approximately 12 foot by 12 foot building located on the
shore of Jim’s Lake. It will house the crossflow turbine, generator, controls, and switchgear for
the upper system. After passing through the turbine, water will be discharged via an enclosed
Elfin Cove Hydroelectric Project Conceptual Design and Development Plan
Letter Report Polarconsult Alaska, Inc.
January 20, 2014 Page 8 of 11
pipe into Jim’s Lake. The pipe tailrace will extend below the minimum drawdown elevation of
the lake (330 feet) to reduce erosion of the lakebed.
Lower System
The lower system intake will consist of a screened siphon intake positioned at approximately
322‐foot elevation in Jim’s Lake. At the proposed intake site, this will provide approximately 8
feet of cover at maximum lake drawdown and 5 feet of vertical separation to the lake bed to
minimize uptake of bottom sediments. The intake screen will be fitted with an anchor and float
assembly to facilitate manual hoisting to the surface for cleaning or maintenance when
necessary. The intake will be designed to minimize the need for manual cleaning.
The maximum suction head on the intake will be approximately 13 feet. During normal
operation, the intake will function as a passive siphon. At system startup, the penstock will
need to be primed to start the siphon. A small building (approximately eight foot by 10 foot)
located near the lake outlet and high point of the penstock will house a vacuum pump system
that will prime the penstock when needed. This vacuum system will pull air out of the
penstock, drawing water up from the lake and into the penstock until the penstock is filled.
The intake / penstock will be a 14‐inch diameter pipe approximately 2,030 feet long. Pipe
pressure ratings will vary from SDR 26 to SDR 15.5, depending on vacuum and pressure loadings
on the pipe.
Approximately 1,050 feet of the lower penstock will be buried under the access trail.
Approximately 550 feet of the lower penstock will be installed overland, either above grade or
shallow burial, in between trail switchbacks. The remaining approximately 430 feet of the
penstock is located in Jim’s Lake.
The lower powerhouse will be located at the head of Little Sandy Beach with a finished floor
elevation of 24 feet. It will house the turbine (Pelton or Turgo), generator, switchgear, and
controls for the lower system. After passing through the turbine, water will exit the
powerhouse via a concrete tailrace, transitioning to a cobble tailrace. Water will flow down the
cobble beach through the intertidal zone and into Port Althorp.
Elfin Cove Hydroelectric Project Conceptual Design and Development Plan
Letter Report Polarconsult Alaska, Inc.
January 20, 2014 Page 9 of 11
5.2 Alternate Project Configurations Considered
Several alternatives to the recommended project configuration were analyzed to determine the
optimal project configuration given existing hydrology and utility load information. These
alternatives are described below.
Alternate 1: No Power Recovery Turbine on Upper System.6
This alternative is the same as the base configuration only without the power recovery turbine
on the upper system between Crooked Creek and Jim’s Lake. This results in the following major
changes from the base configuration:
● Eliminate control wire up to Crooked Creek diversion site.
● Replace upper powerhouse with a simple energy dissipation structure at the pipe outlet.
● Eliminate approximately 350’ of communications and power to the upper powerhouse
site on the shore of Jim’s Lake.
The upper system power recovery turbine provides approximately 20% of the total project
output. Without this power recovery turbine, the volume of electric utility diesel fuel displaced
by the project is reduced approximately 10% to 79% total. In all scenarios analyzed, the power
recovery turbine on the upper system is cost effective.
Alternate 2: Alter Upper System Design Flow (3.25 to 6.5 cfs considered)
Several alternate upper system design flows were analyzed to determine the optimal design
flow of the project. Design flows corresponding to pipe diameters of 10” (3.25 cfs), 12” (5 cfs),
and 14” (6.5 cfs) were analyzed. A project using 12” pipe and 5 cfs design flow was found to
have the highest benefit‐cost ratio, although the difference across the range of pipes and flows
analyzed was very small. The incremental cost of the pipe is essentially the same as the
incremental value of the additional energy generated by the project over the range of piping
considered.
Alternate 3: Alter Lower System Design Flow (3.25 to 6.5 cfs considered)
Several alternate lower system configurations were analyzed to determine the optimal design
flow of the project. Design flows corresponding to pipe diameters of 10” (3.25 cfs), 12” (5 cfs),
and 14” (6.5 cfs) were analyzed. A project using 14” pipe and 6.5 cfs design flow was found to
have the highest benefit‐cost ratio, although the difference across the range of pipes and flows
analyzed was very small. The incremental cost of the pipe is essentially the same as the
incremental value of the additional energy generated by the project over the range of piping
considered.
6 Polarconsult also analyzed a ‘non‐upgradeable’ version of this alternative, with a smaller and shorter pipeline
that would not be suitable for future installation of a power recovery turbine. Both of these alternate
configurations offer significantly reduced energy output and significantly lower benefit cost ratio compared to
the recommended project configuration.
Elfin Cove Hydroelectric Project Conceptual Design and Development Plan
Letter Report Polarconsult Alaska, Inc.
January 20, 2014 Page 10 of 11
6.0 COST ESTIMATE AND PROJECT ECONOMIC EVALUATION
The estimated cost for the recommended project configuration is presented in Table 4. Project
economics are summarized in Table 5.
Table 4: Project Cost Estimate
Cost Item Cost Estimate
PRE‐CONSTRUCTION COSTS (DESIGN & PERMITTING) $380,000
DIRECT CONSTRUCTION COSTS
Access Trails $680,000
Transmission Line $340,000
Upper System
Diversion Structure $74,000
Penstock $55,000
Powerhouse $203,000
Upper System Subtotal $332,000
Lower System
Diversion Structure $65,000
Penstock $145,000
Powerhouse $413,000
Lower System Subtotal $623,000
Shipping $93,000
Equipment / Mobilization $252,000
TOTAL DIRECT CONSTRUCTION COSTS $2,320,000
Construction Management / Administration $120,000
Construction Inspection / Engineering $120,000
Construction Contingency (15%) $440,000
ESTIMATED TOTAL INSTALLED COSTS $3,380,000
Project economics are evaluated using AEA’s renewable energy project economic model
developed by ISER.7 Two economic scenarios are considered: (1), that excess energy generated
by the hydro project is not used, aside from heating the community building and shop to
replace waste heat from the diesel power plant, and (2) that excess energy generated by the
hydro project is used via a dispatchable energy system to heat other buildings in the
community when this energy is available. A dispatchable energy system associated with this
project would produce significant value because the utility load is relatively low during the
winter heating season, so a significant fraction of the hydro project’s output would be available
during the winter months to displace heating fuel.
7 Renewable Energy Project Economic Model, Developed for Alaska Energy Authority by UAA Institute for Social
and Economic Research (ISER). Renewable Energy Grant Program Round 7 Version, Published July 2013.
Elfin Cove Hydroelectric Project Conceptual Design and Development Plan
Letter Report Polarconsult Alaska, Inc.
January 20, 2014 Page 11 of 11
Table 5: Project Economic Summary
1. present value calculated using a 50‐year life and 3% discount rate.
2. Calculated as the sum of nominal annual fuel expenses over 50 years as projected by ISER divided by 50.
3. Assumes 75,000 kWh are dispatched to the community building and shop to replace heat from the diesel
power plant. No benefit is calculated from this energy. 75% of the remaining net excess energy is assumed to
be dispatched to other interruptible loads in the community to displace the indicated quantity of heating oil.
7.0 DEVELOPMENT PLAN
Once the project configuration described in this letter report has been approved by ECUC and
AEA, Polarconsult can proceed with project permitting under the following schedule.
February – May 2014: Agency consultations, permit applications, finalize study plans
June – September 2014: Conduct field studies, agency site visit and public meetings
August – December 2014: Prepare Draft FERC License Exemption Application (DLEA)
January 2015: Circulate DLEA for Agency and FERC Review and Comment
April 2015: Receive comments on DLEA
April – May 2015: Finalize FERC License Exemption Application, file with FERC
June – November 2015: FERC processes application
December 2015: FERC issue License Exemption
Because the permitting process is agency driven, the milestone dates should be viewed as
targets rather than firm deadlines – significant additional information requests, or protracted
negotiations over permit terms can slow down progress. Conversely, close coordination with
and consensus between agencies and the applicant can result in faster progress than outlined
in the attached schedule.
Parameter Value
HYDRO PROJECT COSTS
Project Installed Cost $3.38M
Average Annual Hydro Operations, Maintenance, Repair & Replacement Costs (50 years) $21,000
Salvage Value (at year 50) $0
PRESENT VALUE OF PROJECT COSTS (1) $3.03M
HYDRO PROJECT BENEFITS (UTILITY FUEL SAVINGS ONLY)
Displacement of Energy Generated by Diesel Power Plant (kWh) 266,300
Displaced Diesel Fuel for Power plant (gallons) 21,300
Average Annual Value of Displaced Fuel (50 years) (2) $190,800
PRESENT VALUE OF PROJECT BENEFITS (UTILITY FUEL SAVINGS ONLY) (1) $3.67M
BENEFIT‐COST RATIO (UTILITY FUEL SAVINGS ONLY) 1.21
HYDRO PROJECT BENEFITS (UTILITY FUEL SAVINGS + EXCESS ENERGY USAGE)
Net Excess Hydro Energy Dispatched to Interruptible Loads (kWh per yr) (3) 180,000
Displaced Heating Fuel (gallons per year) (3) 5,300
Average Annual Value of Displaced Heating Fuel (50 years) (2) $52,950
PRESENT VALUE OF PROJECT BENEFITS (INCLUDING EXCESS ENERGY) $4.79M
BENEFIT‐COST RATIO (COUNTING EXCESS ENERGY BENEFIT) 1.58