HomeMy WebLinkAboutMarshall Wind Project Concept Design Report - Oct 2013 - REF Grant 7040021MARSHALL WIND PROJECT
CONCEPT DESIGN REPORT
Prepared By:
Mark Swenson, PE
3335 Arctic Blvd., Ste. 100
Anchorage, AK 99503
Phone: 907.564.2120
Fax: 907.564.2122
October 7, 2013
Prepared For:
Alaska Village Electric Cooperative
4831 Eagle Street
Anchorage, Alaska 99503
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1.0 EXECUTIVE SUMMARY
This report has been prepared for the Alaska Village Electric Cooperative (AVEC) to provide
conceptual design and cost analysis for development of wind power generation in the
community of Marshall, Alaska. Marshall is a rural community of approximately 407 year
round residents located on the north bank of Polte Slough, north of Arbor Island, on the east
bank of the Yukon River in the Yukon Kuskokwim Delta. Integration of wind generated power
into the existing electrical power generation system will offset diesel consumption costs and
provide a renewable energy resource for this rural community.
On December 18, 2008, a meteorological (met) tower was installed along the airport access
road approximately 0.8 miles from Marshall. The met tower collapsed on October 12, 2009 due
to an anchor failure during a strong wind event. The met tower was reinstalled at the same
location during September 2012 to obtain additional wind data. The met tower is equipped
with instrumentation and data loggers to evaluate and record the wind resource. The wind
data collected during the met tower operation suggests that the existing wind regime is suitable
for wind power generation. The results of the data acquisition and analysis of the wind
resource are included in the Marshall Wind Diesel Feasibility Studydated October, 2013
(Appendix A).
On August 7, 2012 AVEC, Hattenburg Dilley & Linnell (HDL), and V3 Energy performed a site visit
to Marshall to investigate three separate locations near the community, where computer
modeling identified good wind resource potential. During the site visit it was confirmed that the
site where the met tower was installed is the most suitable location for installing wind
turbines.
For this report, AVEC selected three wind turbine configurations for evaluation.
The first configuration includes (3) Northern Power 100 Arctic turbines (NP100), formerly
known as the Northwind 100. The Northern Power 100 Arctic turbines installed in Marshall
will include 37 meter (121 foot) monopole towers and 21 meter blades. The NP100s are
permanent magnet, direct drive wind power generator that AVEC previously installed in 10
other villages in rural Alaska. The (3) Northern Power 100 Arctic tower array has a
maximum power generation output of 300 kW.
The second turbine configuration consists of (3) Vestas V20 turbines. The Vestas V20
turbine 120 kW, induction generator, installed on a 32 meter (105 foot) tower. This
configuration has a maximum power generation output of 360 kW and requires a cold
weather kit modification for use in Marshall. The generators will be controlled using a
simple inverter with soft start and soft breaking capabilities or a more complex variable
speed drive (VSD) inverter at each turbine. The turbine blades are fixed pitch.
The third turbine configuration consists of (1) Aeronautica AW33 225 turbine. The AW33
225 turbine is a 225 kW, induction generator, installed on a 40 meter (131 foot) tower. This
configuration has a maximum power generation output of 225 kW. The generator will be
controlled using a simple inverter with soft start and soft breaking capabilities or a more
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complex variable speed drive (VSD) inverter at each turbine. The turbine blades are stall
regulated to limit rotation speed and torque in extreme wind events.
It is anticipated that the Northern Power 100 turbines and the AW33 225 turbines would be
installed on monopole towers and the V20 turbines would be installed on lattice towers.
Foundations will likely include precast concrete gravity mats with rock anchors, if additional
resistance is required to counteract the overturning moment of the turbines. A comparison of
the three turbine configurations installed at preferred location in Marshall is presented in
Tables EX 1 and EX 2 below.
Table EX 1: Turbine Alternative Comparison Summary
Alt Turbine Selection Site Generation
Capacity (kW)
Estimated
Capital Cost
Estimated
Capital Cost
per Installed
kW
Estimated
Annual Energy
Production
@ 100 %
Availability
1 (3) NP 100s Met Tower 300 $ 3.2 M $10,580 779,125 kWh
2 (3) V20s Met Tower 360 $ 2.9 M $8,029 718,989 kWh
3 (1) AW33 225 Met Tower 225 $ 2.7 M $11,824 653,658 kWh
Source: Annual Energy Production data taken from V3 Energys October 2013 Marshall Wind Diesel Feasibility
Analysis
Table EX 2: Economic Analysis Summary
Alt
Annual Wind
Generation @
80% Availability
(kWh)
Wind Energy For
Power (kWh/yr)
Wind
Energy For
Heat
(kWh/yr)
Wind as %
Total Power
Production (%)
Power
Generation:
Fuel Displaced
by Wind
Energy (gal/yr)
Heating Fuel
Displaced By
Wind Energy
(gal/yr)
1 623,300 523,707 99,593 37.4 48,893 2,546
2 575,191 471,521 103,670 34.6 38,977 2,650
3 522,926 467,889 55,037 31.4 37,454 1,407
Source: Annual Energy Production data taken from V3 Energys October 2013 Marshall Wind Diesel Feasibility
Analysis
We recommend AVEC proceed with design and permitting for installation of Alternative 1
(three Northern Power 100 Arctic turbines) in Marshall. This alternative is recommended
because it maximizes the power output for Marshalls wind regime. Also, as described in detail
in the report, the NP100 option matches the majority of the wind turbine fleet that AVEC has
installed in other villages throughout Alaska. AVECs Operations staff is familiar with this
turbine and maintenance and replacement parts are already in stock or readily available.
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Table of Contents
1.0 EXECUTIVE SUMMARY...........................................................................................................i
1.0 INTRODUCTION.................................................................................................................... 1
1.1 BACKGROUND....................................................................................................................... 1
1.2 LOCATION.............................................................................................................................. 2
1.3 CLIMATE................................................................................................................................ 2
1.4 ELECTRICAL DEMAND ........................................................................................................... 2
1.5 EXISTING ELECTRICAL POWER SYSTEMS............................................................................... 3
1.6 MARSHALL RECOVERED HEAT POTENTIAL ........................................................................... 3
1.7 TRANSMISSION LINE EXTENSIONS........................................................................................ 4
1.8 REQUIRED POWER PLANT IMPROVEMENTS......................................................................... 4
1.9 GEOTECHNICAL INFORMATION............................................................................................ 4
1.10 LIMITATIONS....................................................................................................................... 5
2.0 MARSHALL WIND SITE ANALYSIS......................................................................................... 5
2.1 WIND TURBINE SITE INVESTIGATION ................................................................................... 5
2.1.1 METEOROLIGICAL (MET) TOWER SITE...................................................................... 6
2.1.2 ALTERNATIVE SITE 1.................................................................................................. 7
2.1.3 ALTERNATIVE SITE 2.................................................................................................. 7
2.1.4 ALTERNATIVE SITE 3.................................................................................................. 8
3.0 WIND DATA ACQUISITION AND MODELING........................................................................ 9
3.1 MARSHALL WIND RESOURCE................................................................................................ 9
4.0 WIND TURBINE SYSTEM ALTERNATIVES............................................................................ 10
4.1 MARSHALL WIND TURBINE ANALYSIS ................................................................................ 10
4.1.1 NORTHERN POWER 100 ARCTIC............................................................................. 10
4.1.2 Vestas V20............................................................................................................... 11
4.1.3 Aeronautica AW33 225........................................................................................... 11
4.2 ALTERNATIVE 1 (3) NP100 TURBINES ............................................................................ 12
4.3 ALTERNATIVE 2 (3) V20 TURBINES.................................................................................. 12
4.4 ALTERNATIVE 3 (1) AW33 225 TURBINES....................................................................... 12
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4.5 ALTERNATIVE COMPARISON SUMMARY............................................................................ 13
5.0 ECONOMIC EVALUATION................................................................................................... 13
5.1 METHODOLOGY AND APPROACH....................................................................................... 13
5.2 ECONOMIC EVALUATION RESULTS..................................................................................... 14
6.0 PREFERRED ALTERNATIVE.................................................................................................. 14
7.0 PERMITTING, ENVIRONMENTAL, AND LAND OWNERSHIP ............................................... 15
7.1 FEDERAL AVIATION ADMINISTRATION (FAA)..................................................................... 15
7.2 US FISH AND WILDLIFE SERVICE (USFWS) .......................................................................... 15
7.3 STATE HISTORIC PRESERVATION OFFICE (SHPO)................................................................ 16
7.4 DEPARTMENT OF THE ARMY (DA)...................................................................................... 17
7.5 CONTAMINATED SITES, SPILLS, AND UNDERGROUND TANKS........................................... 17
7.6 AIR QUALITY........................................................................................................................ 17
7.7 NATIONAL ENVIRONMENTAL POLICY ACT REVIEW (NEPA)................................................ 17
7.8 LAND OWNERSHIP.............................................................................................................. 18
8.0 CONCLUSIONS AND RECOMMENDATIONS........................................................................ 18
9.0 REFERENCES....................................................................................................................... 19
FIGURES
Figure 1: AEA Wind Resource Map................................................................................................. 1
Figure 2: Wind Tower Site Alternatives.......................................................................................... 6
Figure 3: Airport Access Road Adjacent to Met Tower Site and Alternative Site 1....................... 7
Figure 4: Alternative Site 2............................................................................................................. 8
Figure 5: UUI Access Road and Utility Poles on Approach to Alternative Site 3............................ 9
Figure 6: NP100 Turbine Installed in Emmonak .......................................................................... 11
TABLES
Table 1: Energy Consumption Data ............................................................................................... 3
Table 2: Alternative Comparison Summary.................................................................................. 13
Table 3: Economic Evaluation Summary....................................................................................... 14
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APPENDICIES
Appendix A: V3 Energys October 2013 Marshall Wind Diesel Feasibility
Appendix B: ANTHC Marshall Alaska Heat Recovery Study
Appendix C: August 3, 2012 Marshall Wind Site Investigation Report
Appendix D: Marshall Wind Project Feasibility Design Drawings
Appendix E: Concept Level Capital Cost Estimate
Appendix F: FAA Permitting
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ABBREVIATIONS
AAC Alaska Administrative Code
ADEC Alaska Department of Environmental Conservation
ADF&G Alaska Department of Fish and Game
ADNR Alaska Department of Natural Resources
AEA Alaska Energy Authority
AHRS Alaska Heritage Resource Survey
AVEC Alaska Village Electric Cooperative
B/C Benefit to Cost Ratio
CRC Cultural Resource Consultants, LLC
DA Department of Army
EA Environmental Assessment
ER Environmental Review
FAA Federal Aviation Administration
FY Fiscal Year
FONSI Finding of No Significant Impact
°F Degrees Fahrenheit
HDL Hattenburg Dilley & Linnell
ISER Institute for Social and Economic Research
kW Kilowatt
kWh Kilowatt Hour
M Million
MBTA Migratory Bird Treaty Act
Met Meteorological
Mph Miles per hour
MWh Megawatt hour
NLUR Northern Land Use Research
NP100 Northern Power 100 Arctic
NWI National Wetlands Inventory
NWP Nationwide Permit
OEAAA Obstruction Evaluation/Airport Airspace Analysis
PCE Power Cost Equalization
PCN Pre Construction Notification
SCADA Supervisory Control and Data Acquisition
Sec Section
USFWS United States Fish & Wildlife Services
USGS United States Geological Services
WAsP Wind Atlas and Application Program
Yr Year
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1.0 INTRODUCTION
1.1 BACKGROUND
This report has been prepared for the Alaska Village Electric Cooperative (AVEC). The purpose
of this report is to provide AVEC with conceptual design and cost information for the feasibility
of developing the wind energy resource in Marshall. Analysis in this report includes an
assessment of the wind resource, investigation and selection of wind turbine installation
locations, evaluation of permitting required for site development, preliminary wind turbine
generator comparison, and economic analysis of selected turbine alternatives.
The wind turbines are necessary to reduce AVECs dependence on diesel fuel and provide a
source of renewable energy. Preliminary findings included in the Alaska Energy Authority (AEA)
Alaska high resolution wind resource map indicate that the Marshall region has a Class 4 wind
regime suitable for wind power development.
Figure 1: AEA Wind Resource Map
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1.2 LOCATION
The proposed wind turbine project is located near the village of Marshall. Marshall is a rural
community located on the north bank of Polte Slough, north of Arbor Island, on the east bank
of the Yukon River in the Yukon Kuskokwim Delta. It lies approximately 75 air miles northeast
of Bethel at approximately 61.878° North Latitude and 162.081° West Longitude (Sec. 27,
T021N, R070W, Seward Meridian). Marshall is located in the Bethel Recording District. No
roads connect Marshall to the rest of the state, so access is primarily by air or water. Marshall
has a state owned gravel airstrip providing year round access on a 3,200long and 100wide
runway. Barge service is available seasonally from approximately mid June through October.
Marshall has a population of 407 year round residents (2010 U.S. Census Population), with
94.7% being Alaska Native or American Indian. The local residents depend heavily on the
subsistence harvest of fish, moose, bear, and waterfowl. The economy is based on a mix of
commercial fisheries and public sector jobs.
1.3 CLIMATE
Marshall has a maritime climate with extreme temperatures ranging from 54°F to 86°F.
Average annual precipitation measures 16 inches. Average summer temperatures range from
40 to 60°F. Winters are typically cold and dry with average winter temperatures ranging from 5
to 15°F.
1.4 ELECTRICAL DEMAND
Historical AVEC and AEA Power Cost Equalization Program (PCE) report data was analyzed to
determine trends in Marshalls energy consumption. The Alaska PCE program is a reliable
source of historic power, fuel consumption, and energy cost information for rural communities
throughout the state. The PCE program provides funding subsidies to electric utilities in rural
Alaskan communities for the purpose of lowering energy costs to customers. This program pays
for a portion of kilowatt hours sold by the participating utility. The exact amount paid varies per
location, and is determined by the amount of energy generated and sold, the amount of fuel
used to generate electricity, and fuel costs.
Each year, AEA publishes PCE program information including fuel consumption, power
generation and sales, and electricity rates for eligible communities. During the fiscal year 2012
(July 1, 2011 to June 30 2012), 126 residential and community facilities in Marshall were eligible
to receive PCE assistance. Marshall customers received funding for 42.3% of kilowatt hours
sold and had electricity rates reduced from an average of 58 cents per kilowatt hour to 22 cents
per kilowatt hour. Table 1 provides FY 2012 PCE and AVEC generated diesel and electricity
statistics for Marshall.
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Table 1: Energy Consumption Data
Community Gross
KWhs
Generated
Diesel Fuel Used
Average
kWh Load
Peak kWh
Load
Customers
(Residential
and
Community
Facilities)
Gallons Cost ($)Average
Fuel Price
($/gallon)
Diesel
Efficiency
(kWh/gallon)
Marshall 1,643,535 126,625 408,268
3.22 12.97 190 339 150
*Source: 2012 AVEC Annual Generation Report, AVEC Operations Personnel, and Annual PCE Report FY 2012
AVEC recorded data from December 2011 to December 2012 shows Marshalls average load
was 190 kW with a peak load at 339 kW. Winter electrical demands increase approximately
50% compared to summer demand, with data showing the average load in June and July was
approximately 150 kW compared to approximately 220 kW in January and February.
1.5 EXISTING ELECTRICAL POWER SYSTEMS
Existing Marshall Power Plant:
AVECs power plant is located within the community of Marshall. The plant was first energized
in 1971 and consists of a Butler Building,wood dock, control module, storage van, crew
module, and pad mounted transformers. The building and modules are constructed on a
mixture of elevated timber post, grade beam and crib foundations. The Butler Building
contains the following generator sets:
(1) Cat 3456 with Cat LC6 Generator, rated at 500KW
(1) Detroit Series 60 DDEC4 with Kato 6P4 1450, rated at 363KW
(1) Detroit Series 60 DDEC4 with Kato 6P4 1450, rated at 236KW
1,099 kW Total Generation Capacity
The power plant also includes generator appurtenances, day tank, miscellaneous tools and
equipment, transfer pump, starting batteries, and station service equipment. The building
contains a combined cooling system for all three generators with two remote radiators. Power
is generated at 277/480V three phase and there are five fused distribution switches that
distribute power to the village, one switch is a low voltage feed to the water plant, one is a
single phase switch feeding the west part of town and the other three are A, B, and C
switches feeding the east part of town, the school, and airport. Distribution voltage is 7200V.
According to historic AVEC records, the power plant generated a total of 1,644,176 kWh and
sold a total of 1,594,247 kWh in 2012 with an average of 12.98 kWh per gallon of diesel
consumed.
1.6 MARSHALL RECOVERED HEAT POTENTIAL
The Alaska Native Tribal Health Consortium (ANTHC) Division of Environmental Health and
Engineering prepared a Heat Recovery Study dated July 16, 2012. The report provides the
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findings for utilizing recovered heat from the existing power plant to heat the existing
community store and water treatment building. According to the report, a heat recovery
system was installed in 2007 in the existing power plant but it did not work as designed.
Funding to repair the existing recovered heat system was awarded to the City in Round 6 of the
AEA Renewable Energy Grant Fund and system repairs a currently being designed. The ANTHC
report shows thermal load demand on the existing recovered heat system in Marshall is far less
than available heat from the existing generators and the all heat demand will be met by the
generators when the existing recovered heat system is operational. See Appendix B for the
ANTHC heat recovery study.
Since the current loads on the recovered heat system will be met by the waste heat from the
generators, a better option to use excess wind energy from wind turbines is to install an electric
boiler secondary load controllers remotely in the school boiler room and teacher housing
complex. The school is not currently connected to the recovered heat loop. Therefore, excess
wind power could by pass the existing recovered heat system and be used to offset
approximately 2,546 gallons of fuel oil currently used to heat the school facilities.
1.7 TRANSMISSION LINE EXTENSIONS
Currently three phase transmission lines are installed from the AVEC power plant to the existing
school which is approximately 0.6 miles from the Met Tower Site. Utility poles with
communication wires are already in place along the airport access road, which extends beyond
the Met Tower Site to the United Utilities Inc. (UUI) communication tower. These existing
utility poles will likely accommodate the future wind power transmission lines.
1.8 REQUIRED POWER PLANT IMPROVEMENTS
Upgrades to the existing power plant switch gear and control panels are anticipated in order to
accommodate wind turbine energy. AVEC is currently evaluating the power plant and will
provide recommendations for necessary upgrades in the early stages of the design phase. The
preliminary cost estimate included in this report considers the costs for replacement of the
existing switch gear and upgrades to the control panels.
1.9 GEOTECHNICAL INFORMATION
The Alaska Department of Transportation performed a geotechnical investigation in 1997 along
the alignment of what is now the existing airport access road. The results of their findings are
published in the July 1998 Geotechnical Report for Marshall Airport Runway Relocation.Two of
the boreholes from that investigation were advanced on August 28, 1997 within approximately
400 feet of the met tower installation location. These boreholes indicate ice rich fine grained
soils to a depth of 9and 11.5below ground surface. The drill encountered refusal in both
boreholes, interpreted as bedrock.
From the above referenced report, bedrock in the Marshall area is known to consist of both
Permio Triassic metavolcanic and metasedimentary rocks, and Cretaceous igneous rocks. The
metamorphic rocks have been recrystallized locally to hornfels by contact metamorphism
where they are near igneous intrusive rocks. The metamorphic rocks are mostly gray and green,
fine to medium grained, and massive to schistose. The Cretaceous igneous rocks are medium
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grained, light gray to greenish gray and weakly foliated. Small bodies of intrusive granitic rock
have been mapped on the surrounding mountains, and a small light green gray granodiorite is
exposed in the material site near the abandoned former runway at Marshall.
Due to the presence of different rock types and variable degrees of hornfelsing around the
intrusive rocks, the metavolcanic and metasedimentary rocks probably exhibit variable degrees
of competence in the project area. A site specific geotechnical investigation is needed to
support the selection of a wind turbine foundation type and to formulate a detailed foundation
design. Based on existing information a mass gravity foundation with rock anchors will likely be
utilized.
1.10 LIMITATIONS
This report, titled Marshall Wind Project Concept Design Report,was prepared in support
of a grant funding request for design and permitting a wind tower project in Marshall,
Alaska. Design information contained herein is conceptual for planning and budgetary cost
estimation purposes only.
2.0 MARSHALL WIND SITE ANALYSIS
2.1 WIND TURBINE SITE INVESTIGATION
On August 3, 2012, Brent Petrie (AVEC), Matt Metcalf (AVEC), Doug Vaught (V3 Energy), and
Ryan Norkoli (HDL) traveled to Marshall. The purpose of the site visit was to investigate the
Met Tower Site (described below) and three additional potential wind sites that had been
identified through WAsP wind modeling software as possible alternatives to the Met Tower
Site, see Figure 1 for locations of the Met Tower Site and three alternative sites. A memo
summarizing preliminary office research and the trip report for the site investigation is included
in Appendix C. Upon completion of the site investigation, the existing Met Tower Site was
determined to be the most cost effective location for installing wind turbines near Marshall.
Below is a summary of each potential wind turbine site.
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Figure 2: Wind Tower Site Alternatives
2.1.1 METEOROLIGICAL (MET) TOWER SITE
The met tower site is located at 61û5233.3North Latitude, 162û0355.98West Longitude. At
this location a met tower was installed to record data starting on December 18, 2008 and
collapsed October 12, 2009 due to an anchor failure. Low lying tundra vegetation covers the
area and the topography is generally flat. The site is adjacent to the existing airport access road
and communication wires are strung across utility poles adjacent to the airport access road.
These existing poles would likely accommodate transmission lines to route power to the plant.
A 1998 geotechnical report developed by the Alaska Department of Transportation (ADOT)
provides borehole information within 400 feet of this location. Upon review of other available
sites, the met tower site was the preferred site for wind tower development.
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Figure 3: Airport Access Road Adjacent to Met Tower Site and Alternative Site 1
2.1.2 ALTERNATIVE SITE 1
Alternative Site 1 is located at 61û5222.78North Latitude, 162û0407.79West Longitude. This
location was identified though wind modeling to have 7% greater annual energy production
(AEP) than the Met Tower Site. Although the site development costs would be comparable to
the Met Tower Site, Alternative Site 1 is located within an existing Native Allotment (NA) and
due to property ownership limitations, the location was eliminated from further consideration.
2.1.3 ALTERNATIVE SITE 2
Alternative Site 2 is located at 61û5309.58North Latitude, 162û0259.58West Longitude.
Alternative Site 2 wind modeling indicates 3% less AEP compared to the Met Tower Site. The
site is located approximately 1 mile further from the AVEC power plant than the Met Tower
Site. Alternative 2 site development would result in additional transmission line costs and site
development costs for a lower quality wind source compared to the Met Tower Site.
Alternative Site 2 was eliminated from consideration.
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Figure 4: Alternative Site 2
2.1.4 ALTERNATIVE SITE 3
Alternative Site 3 is located at 61û5343.99North Latitude, 162û0308.6West Longitude.
Alternative Site 3 was identified through wind modeling to have 14% greater AEP than the Met
Tower Site. The site is located approximately 1.5 miles from the existing maintained road
system. The area is accessed via a rough single lane gravel trail which follows the existing
United Utilities Inc. (UUI) communication lines alignment to a communication tower on a
nearby mountain top. The existing utility poles that route communication lines back to
Marshall would likely be able to accommodate power transmission lines. However, some of the
existing utility poles are leaning over due to inadequate foundation soil support. The utility
poles were installed within the last 5 years and considering the amount of movement that has
already taken place, maintenance costs and useful life are significant concerns with this site.
Due to the following considerations, Alternative Site 3 was not selected for further evaluation:
higher initial construction costs, increased maintenance concerns for transmission lines, line
losses due to additional transmission length, and lack of year round overland access to the site.
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Figure 5: UUI Access Road and Utility Poles on Approach to Alternative Site 3
3.0 WIND DATA ACQUISITION AND MODELING
3.1 MARSHALL WIND RESOURCE
On December 18, 2008, a meteorological (met) tower was installed along the airport access
road approximately 0.8 miles from Marshall. The met tower collapsed on October 12, 2009 due
to an anchor failure during a strong wind event. The met tower was reinstalled at the same
location in September 2012 to obtain additional wind data and fill in data gaps for the portion
of the year that no site specific data exists. It should be noted that the met tower failed in 2009
during a strong wind event and the months which no data exists for are likely conducive to
power generation. The met tower is equipped with instrumentation and data loggers to
evaluate and record the wind resource. The wind data collected during met tower operation
suggests that the existing wind regime in this location is suitable for wind power generation.
The results of the data acquisition and analysis of the wind resource are included in Marshall
Wind Diesel Feasibility Studydated October, 2013 (Appendix A).
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4.0 WIND TURBINE SYSTEM ALTERNATIVES
4.1 MARSHALL WIND TURBINE ANALYSIS
Three types of wind turbines were selected by AVEC for preliminary cost analysis to assess cost
feasibility: Northern Power Systems Arctic (NP100) turbines; Vestas V20 turbines; and the
Aeronautica AW22 225. These turbines were selected because they can be installed in
configurations that provide 225 kW to 360 kW to the existing power generation system and
have fixed pitch blades. These configurations are classified as medium wind diesel penetration
systems having a goal to offset 20% to 50% of the communitys energy demand with wind
power. A medium penetration system provides a balance between the amount of energy
provided and the complexity of the wind generation and integration systems.
4.1.1 NORTHERN POWER 100 ARCTIC
The analyzed turbine configuration consists of (3) NP100 turbines on 37 meter monpole towers.
The NP100s are manufactured by Northern Power Systems in Barre, Vermont. The NP100
turbine is normally rated at 100 kW. The NP 100s are permanent magnet, synchronous, direct
drive wind power generators. AVEC has previously installed similar turbines with hub heights
ranging 30 to 37 meters, in the following rural Alaska villages:
Chevak 400 kW
Emmonak 400 kW
Gambell 300 kW
Hooper Bay 300 kW
Kasigluk 300 kW
Mekoryuk 200 kW
Quinhagak 300 kW
Savoonga 200 kW
Shaktoolik 200 kW
Toksook Bay 400 kW
3,000 kW AVECs Existing Total NP100 Power Generation Capacity
Each turbine is equipped with active yaw control, but does not have blade pitch control
capability.
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Figure 6: NP100 Turbine Installed in Emmonak
4.1.2 Vestas V20
The second option is installing (3) remanufacturer Vestas Wind Systems A/S V20 turbines. The
V20 is a 120 kW rated, fixed pitch turbine with active yaw and a high speed rotor with three
blades. Vestas is an international turbine manufacturer based in the Denmark, with their
American operations based in Portland, Oregon. The V20s were commonly used as small scale
industrial wind turbines in the 1980s and 1990s. More recently, these turbines have been
replaced in wind farms with new large scale turbines with 1 megawatt capacity or greater. The
decommissioned V20s were sold to independent contractors, such as Halus Power Systems in
San Leandro, CA, for refurbishment and resale. The V20 is a 32 meter (85 foot) high, 120 kW,
induction generator. The turbines are equipped with a 20 meter diameter rotor. Installing
three V20s in Marshall would produce a maximum output of 360 kW at a wind speed of 15
mph. The generator power output can be controlled using a simple inverter and soft breaking
or a variable speed drive (VSD) complex inverter. V20 turbines are the same wind turbines as
the Vestas V17 (except that the blades are 20 meters long instead of 17 meters long). V17
turbines have been previously installed in Alaska at Kokhanok.
4.1.3 Aeronautica AW33 225
The third turbine option is installing one Aeronautica AW33 225 turbine. Aeronautica
Windpower Inc. started in 2008 as a turbine refurbishment company. In 2010 they purchased
the rights to manufacture and sell the Norwin 225 and Norwin 750 turbines under their name.
The AW33 225 turbine is a 40 meter (131 foot) high, 225 kW, induction generator. The
turbines are equipped with a 33 meter diameter rotor. This configuration has a maximum
power generation output of 225 kW. The blades are fixed pitch and stall regulated at high wind
speeds. The blades are aerodynamically designed to stall during extreme wind events in order
to maintaining a safe operating speed. This method of control eliminates the mechanical and
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electric blade control systems involved with pitch controlled turbines. There are no
Aeronautica turbines installed in Alaska at this time.
4.2 ALTERNATIVE 1 (3) NP100 TURBINES
This alternative proposes installation of (3) NP100 turbines at met tower for a total cumulative
generation capacity of 300 kW. The project includes construction of 900 feet of 16 foot wide
gravel access trail and (3) 2,600 square foot gravel pads at the wind tower locations. The
proposed trail and wind tower pads are anticipated to be 4 feet thick and consist of locally
available sands and gravels compacted to 90% maximum density. The turbines are installed on
a 37 meter high, lattice tower. The tower foundation is anticipated to include precast concrete
gravity above shallow volcanic bedrock. Power is delivered from the wind turbines to the
Marshall power plant by a 0.8 mile long transmission line. Reference Sheet C1.02, Appendix D
for a site plan of Alternative 1.
The wind farm modeling included V3 Energys October, 2013 Marshall Wind Diesel Feasibility
Analysis (Appendix A) predicts that this alternative will add 623 MWh/year of annual energy
production to the Marshall power generation system at 80% turbine availability. The
construction cost for this alternative is estimated to be $10,580 per installed kW assuming the
new power plant is complete and operational. See Capital Cost Estimate included in Appendix E.
4.3 ALTERNATIVE 2 (3) V20 TURBINES
This alternative proposes installation of (3) V20 turbines at the met tower site for total
cumulative generation capacity of 360 kW. The project includes construction of 900 feet of 16
foot wide gravel access trail and (3) 2,600 square foot gravel pads at the wind tower locations.
The proposed trail and wind tower pads are anticipated to be 4 feet thick and consist of locally
available sands and gravels compacted to 90% maximum density. The turbines are installed on
a 32 meter high lattice tower. The tower foundation is anticipated to include precast concrete
gravity above shallow volcanic bedrock. Power is delivered from the wind turbines to the
Marshall power plant by a 0.8 mile long transmission line. Reference Sheet C1.03, Appendix D
for a site plan of Alternative 2.
The wind farm modeling included V3 Energys October, 2013 Marshall Wind Diesel Feasibility
Analysis (Appendix A) and predicts that this alternative will add 575 MWh/year of annual
energy production to the Marshall power generation system at 80% turbine availability . The
construction cost for this alternative is estimated to be $8,029 per installed KW assuming the
new power plant is complete and operational. See Capital Cost Estimate included in Appendix E.
4.4 ALTERNATIVE 3 (1) AW33 225 TURBINES
This alternative proposes installation of (1) AW33 225 turbines at met for a potential
generation capacity of 225 kW. The project includes construction of a 300 foot gravel access
trail and (1) 2,600 square foot wind tower pads. The proposed trail and wind tower pads are
anticipated to be 4 feet thick and consist of locally available sands and gravels compacted to
90% maximum density. The turbine is installed on a 40 meter high, conical, monopole tower.
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The tower foundation is anticipated to include precast concrete gravity mats with rock anchors
to resist the increased overturning moment. The AW33 225 towers are anticipated to require
larger foundations than the NP100 turbines due to larger reaction forces from the increased
tower weight, longer blade diameters, and increased swept area. Power is delivered from the
wind turbines to the Marshall power plant by a 0.75 mile long transmission line. Reference
Sheet C1.04, Appendix D, for a site plan of Alternative 3.
The wind farm modeling included V3 Energys October 2013 Marshall Wind Diesel Feasibility
Analysis (Appendix B) and predicts that this alternative will add 522 MWh/year of annual
energy production to Marshall power generation system at 80% turbine availability . The
construction cost for this alternative is estimated to be $11,824 per installed KW assuming the
new power plant is complete and operational and 225 kW of power is delivered from the new
turbine. See Capital Cost Estimate included in Appendix E.
4.5 ALTERNATIVE COMPARISON SUMMARY
Table 2 below summarizes the capital costs and estimated annual energy production for each
turbine alternative.
Table 2: Alternative Comparison Summary
Alt Turbine Selection Site
Generation
Capacity (kW)
Estimated
Capital Cost
Estimated Capital
Cost per Installed
kW
Estimated Annual
Energy Production
@ 80 %
Availability
1 (3) NP 100s Met Tower 300 $ 3.2 M $10,580 721,365 kWh
2 (3) V20s Met Tower 360 $ 2.9 M $8,029 579,681 kWh
3 (1) AW33 225 Met Tower 225 $ 2.7 M $11,824 520,962 kWh
*Source:Annual Energy Production data taken from V3 Energys October 2013 Marshall Wind Diesel Feasibility Analysis
5.0 ECONOMIC EVALUATION
5.1 METHODOLOGY AND APPROACH
The Marshall Wind Diesel Feasibility Analysis prepared by V3 Energy (Appendix A) includes a
wind power analysis of the Marshall power generation system using HOMER energy modeling
software with the previously described wind turbine alternatives. The software was configured
for a medium, with the first priority to meet the communitys electrical demands and the
second priority to serve the recovered heat system through a secondary load controller (electric
boiler). The analysis considered an average diesel fuel price of $4.99 per gallon for the
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projected 20 year project life. The modeling assumptions and results of V3s analysis are
presented in Appendix A.
V3 inserted the power generation and fuel consumption results from the HOMER modeling into
the economic modeling program developed by the Institute for Social and Economic Research
(ISER). AEAs uses the ISER economic model as the standard approach for scoring wind project
design and construction grant applications. The ISER model considers the capital cost of
construction and annual cost of operating and maintaining the wind turbines and weighs them
against the benefit cost savings realized from the volume of displaced diesel fuel required for
power generation and heating public facilities. The analysis develops a benefit/cost ratio that
can be used to compare wind turbine alternatives. See V3s economic analysis results in
Appendix A.
5.2 ECONOMIC EVALUATION RESULTS
Table 3 below summarizes the findings of the V3s economic evaluation for each turbine
alternative.
Table 3: Economic Evaluation Summary
Alt
Annual
Wind
Generation
@ 80%
Availability
(kWh)
Wind
Energy
For Power
(kWh/yr)
Wind
Energy
For Heat
(kWh/yr)
Wind as %
Total
Power
Production
(%)
Power
Generation:
Fuel
Displaced by
Wind Energy
(gal/yr)
Thermal
Generation:
Heating Fuel
Displaced by
Wind Energy
(gal/yr)
Benefit/ Cost
Ratio
1 623,300 523,707 99,593 37.4 42,893 2,546 0.95
2 575,191 471,521 103,670 34.6 38,977 2,650 0.95
3 522,926 467,889 55,037 31.4 37,454 1,407 0.99
*Source:Annual Energy Production data taken from V3 Energys October 2013 Marshall Wind Diesel Feasibility Analysis
6.0 PREFERRED ALTERNATIVE
Based on the findings of the site analysis, wind modeling, and economic evaluation, Alternative
1 is the preferred alternative for Marshall wind turbine development. This alternative consists
of construction of (3) NP100 turbines at the Met Tower Site. Each turbine has the potential to
generate 100 kW, for an aggregate total power generation of 300 kW. The NP100 turbine is the
preferred alternative because it maximizes power production and matches AVECs existing
turbine fleet so that maintenance and operational procedures are consistent among AVEC
turbine installations. The three turbine installation would allow for redundancy in the system
and the ability to perform turbine maintenance without eliminating wind power from the
system. The economic evaluation above assumes that the turbine array operates at the 300 kW
energy output level. However, for better system performance, the turbine should be modulated
by occasionally shutting down turbines to consistently provide medium penetration to the
Marshall grid and adequate excess energy to meet recovered heat demands.
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7.0 PERMITTING, ENVIRONMENTAL, AND LAND OWNERSHIP
7.1 FEDERAL AVIATION ADMINISTRATION (FAA)
The FAA requires an Obstruction Evaluation/Airport Airspace Analysis (OE/AAA) and submittal
of a Notice of Proposed Construction or Alteration (45 days prior to construction) for projects
proposing construction or alteration of any of the following:
1. A structure that exceeds 200 feet above ground level
2. A structure located in proximity to an airport and will not exceed the slope ratio
3. A structure involving construction of a traverse way
4. A structure emitting frequencies, and does not meet the conditions of the FAA Co
location Policy
5. A structure located in an instrument approach area that might exceed part 77 Subpart C
6. A structure located on an airport or heliport
On November 13, 2012, a Determination of No Hazard to Air Navigation from the FAA was
issued for two Northern Power 100 wind turbines (Reference No. 2012 WTW 7872 OE and
2012 WTW 7873 OE) at the met tower site. See Appendix F for FAA determinations. This
determination will have to be modified based on the final tower configuration determined
during design.
7.2 US FISH AND WILDLIFE SERVICE (USFWS)
Marshall is located within the Yukon Kuskokwim Delta Ecoregion and lies on the northeastern
boundary of the Yukon Delta National Wildlife Refuge. According to Alaskas 32 Ecoregions:
The area is characterized by lakes, streams, tidal flats, wet tundra, and sedge flats that support
an abundant population of waterfowl and shorebirds; providing breeding grounds for more
than 20 species of waterfowl and 10 species of shorebirds. The Yukon Kuskokwim Delta
supports 50% of the worlds black brant, the majority of the worlds emperor geese, all of North
Americas nesting cackling Canada geese, and the highest density of nesting tundra swans. The
long tailed duck, scaup, common eider, spectacled eider, northern pintail, green winged teal,
and northern shoveler can also be found here.
The USFWS lists the spectacled eider as threatened. Spectacled eiders typically nest on coastal
tundra near shallow ponds or lakes, usually within 10 feet of the water. The current range map
does not depict spectacled eider use of the area. Consultation with USFWS in September 2013
revealed that Marshall is outside the vicinity of expected spectacled eider habitat.
USFWS recommends avoiding vegetation clearing for regions throughout the state of Alaska.
For the Yukon Kuskokwim Delta region the following avoidance periods apply:
1. Shrub and Open Habitat May 5th through July 25th (except in habitat that supports
Canada geese, swan, and black scoter)
2. Canada geese and swan habitat April 20th through July 25th
3. Black scoter habitat May 5th through August 10th
Under the Migratory Bird Treaty Act (MBTA):
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It is illegal for anyone to takemigratory birds, their eggs, feathers or nests.Takeincludes
by any means or in any manner, any attempt at hunting, pursuing, wounding, killing, possessing
or transporting any migratory bird, nest, egg, or part thereof. Take and possession under MBTA
can be authorized through regulations, such as hunting regulations, or permits (e.g., salvage,
research, depredation, or falconry). The MTBA does not distinguish between intentional and
unintentional take. In Alaska, all native birds except grouse and ptarmigan (protected by the
State of Alaska) are protected under the MBTA.
The Yukon Delta National Wildlife Refuge also supports spawning and rearing habitat for 44
species of fish including all five North American Pacific Salmon. A review of ADF&Gs
Anadromous Waters Catalog lists Poltes Slough (AWC Code: 334 20 11000 2375) as the closest
fish bearing stream to the project area. The Slough supports the presence of chum, coho, and
king salmon and connects to the main stem of the Yukon River (AWC Code: 334 20 11000). The
project is located far enough from the Slough that secondary indirect impacts from construction
related activities are unlikely to impact water quality.
Informal Section 7 consultation with USFWS is recommended once the project progresses past
the preliminary site evaluation stage, per USFWS's Land Based wind Energy Guidelines, to
identify potential impacts to general avian species and determine whether measures to avoid
and minimize effects are necessary.
7.3 STATE HISTORIC PRESERVATION OFFICE (SHPO)
Preliminary research by Cultural Resource Consultants, LLC was performed on the Met Tower
Site. According to the Alaska Heritage Resource Survey (AHRS) files there are no known historic
or archaeological sites within the proposed project area. In addition, the project area is located
outside of an area defined as highest potential for cultural resourceswhich extends two to
three blocks from the river and includes a cemetery and two other areas of reported graves.
This high potential area does not include the proposed wind tower locations. An historic and
archaeological survey was conducted along the roadway from the town site of Marshall to the
airstrip. Results of the survey suggested that, although the airport access road had been
constructed prior to the survey, it appeared to have no impact on historic or prehistoric sites.
Preliminary research results did reveal one known historic resource within the proposed project
area, the Paimute Marshall Trail (RST 168). The Paimute Marshall Trail is an historic trail used
as a connecting route from the Yukon River at Paimute through Russian Mission to Marshall.
The trail is shown in the 1973 Department of Transportation and Public Facilities trails
inventory, on Maps 73 and 74 (Russian Mission Quadrangle), as Trail #18. The trail does not
have an AHRS number, but since it is listed as a qualified RS2477 right of way. The Alaska State
Historic Preservation Office indicated that a cultural resources survey would be necessary to
collect information on the Paimute Marshall Trail to evaluate it and determine whether or not
it is eligible for listing on the National Register of Historic Places.
Based on existing AHRS information and the findings of previous investigations, there is a
relatively low probability of undiscovered archaeological and historic sites within area proposed
for development. In accordance with the National Historic Preservation Act, the undertaking
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will need to be reviewed by the SHPO. During formal Section 106 consultation the SHPO will
determine whether additional surveys and mitigation will be required.
7.4 DEPARTMENT OF THE ARMY (DA)
Section 404 of the Clean Water Act requires a permit for placement of fill in wetlands and
waters of the United States. The National Wetlands Inventory (NWI) database does not have
data for the Marshall area. However, current wetland mapping in adjacent areas with similar
habitat and landform features indicates the area contains wetlands under DA jurisdiction.
A new Nationwide Permit (NWP) issued in 2012 for Land Based Renewable Energy General
Facilities (NWP 51) authorizes discharge of fill for wind tower construction if loss of wetlands
does not exceed 1/2 acre. This permit also covers other associated work, including utility lines,
parking lots, and roads inside of the wind generation facility. Access roads and transmission
lines used to connect the facility to existing infrastructure require separate permitting (NWP 12
or 14). Submittal requirements for NWP 51 include Pre Construction Notification (PCN) and
PCN requires a wetlands delineation documenting project impacts.
Completion of wetlands delineation for the area proposed for development is recommended.
The DA recommends that wetlands delineation is completed within the designated growing
season for specific regions. Marshall is located within Alaskas Interior Forested Lowlands and
Uplands Ecoregion, which has a growing season that begins on May 3
rd and ends on October
3rd.
7.5 CONTAMINATED SITES, SPILLS, AND UNDERGROUND TANKS
A search of the Alaska Department of Environmental Conservations (ADEC) contaminated sites
database revealed three active contaminated sites within the Village of Marshall. No known
contaminated sites are located within the area proposed for development.
7.6 AIR QUALITY
According to Alaska Administrative Code (AAC) 18 AAC 50, the community of Marshall is
considered a Class II area. As such, there are designated maximum allowable increases for
particulate matter 10 (PM 10) micrometers or less in size, nitrogen dioxide, and sulfur dioxide.
Activities in these areas must operate in such a way that they do not exceed listed air quality
controls for these compounds. The nature and extent of the proposed project is not likely to
increase emissions or contribute to a violation of an ambient air quality standard or cause a
maximum allowable increase for a Class II area.
7.7 NATIONAL ENVIRONMENTAL POLICY ACT REVIEW (NEPA)
The federal governments role in regulating wind power development is limited to projects
occurring on federal lands or projects that have some form of federal involvement. The federal
nexus for the proposed wind tower site in Marshall is likely with the DA for placement of fill in
wetlands. Construction of the wind towers at the proposed development site would require
preparation of an Environmental Review (ER) document. Similar to an Environmental
Assessment (EA), an ER will provide an assessment of potential environmental impacts and
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Electric Cooperative Concept Design Report
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identify avoidance, minimization, and mitigation measures. A Finding of No Significant Impact
(FONSI) determination by the funding agency will be needed.
Results from a preliminary environmental review are summarized below:
1. In accordance with the National Historic Preservation Act, Section 106 consultation will
be required for the project.
2. A wetlands delineation of the proposed site is necessary to obtain a preliminary
jurisdictional determination and Section 404/10 DA Permit.
3. Informal consultation with the USFWS is recommended to identify potential effects to
threatened or endangered species and possible avoidance and minimization measures.
4. Vegetation clearing shall be scheduled to take place outside appropriate recommended
time periods of avoidance, per the USFWSs recommendations.
5. File FAA form 7460 1 at least 45 days prior to construction. This has been filed for
NP100 turbines.
7.8 LAND OWNERSHIP
The Alaska Department of Natural Resources (ADNR) Special Management Lands Division
indicates the proposed tower site is located within the designated city boundary of Marshall.
The Alaska Division of Community and Regional Affairs (DCRA) Area Use Map for Marshall
indicates the proposed tower site is located on land owned by Maserculiq, Inc. AVEC and
Maserculiq, Inc. have an existing lease agreement in place June 1, 2012 through July 31, 2013
for the installation of the meteorological tower.
8.0 CONCLUSIONS AND RECOMMENDATIONS
The high cost of diesel fuel and available wind resource near Marshall makes wind power an
attractive component to the electrical power generation system. A wind site investigation and
subsequent wind modeling analysis determined that Marshall has a Class 4 wind resource and is
suited for wind site development. Economic analysis of the turbine alternatives presented in
this report included a configuration of three NP100 turbines installed at the Met Tower Site.
The economic analysis projected that three NP100 turbines could offset approximately 42,893
gallons of diesel fuel per year while generating 623,300 kWh/yr.
The following actions are recommended to continue the progress of wind turbine development
in Marshall:
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Recommendations
1. Enter into negotiations with Maserculiq, Inc. for site control and access for a
geotechnical investigation and wind project development at the Met Tower Site.
2. Consult with Marshall community leaders to understand and minimize the impacts to
subsistence activities from wind project development at the Met Tower Site.
3. Perform wetland delineation at the Met Tower Site and proceed with permitting per the
recommendations included in Section 7 of this report.
4. Perform a geotechnical investigation at the Met Tower Site to develop wind tower
foundation design.
5. Perform additional investigation and design of improvements to incorporate wind
power into the existing power plant at Marshall.
6. Continue discussion with Northern Power to determine the NP 100 turbines could be
installed in Marshall with 24 meter blades on 48 meter lattice towers. This
configuration is not currently recommended by Northern Power, but would increase
energy production and better fit Marshalls wind regime.
7. Perform detailed design of a selected alternative, and apply for construction grant
funds.
9.0 REFERENCES
Alaska Community Database, Community Information Summaries (CIS)
http://www.commerce.state.ak.us/dca/commdb/CF_CIS.html, accessed on 9/12/2012
Alaska Energy Authority (AEA).2012. Statistical Report of the Power Cost Equalization Program,
Fiscal Year 2011. Twenty Third Edition. April 2012.
Alaska Department of Environmental Conservation (ADEC).18 AAC 50 Air Quality Control: As
Amended through August 1, 2012.
ADEC. Division of Spill Prevention and Response.Last accessed on September 6, 2012.
http://dec.alaska.gov/applications/spar/CSPSearch/results.asp.
State of Alaska Department of Transportation (ADOT) Northern Region Technical Services
Geology.Geotechnical Report, Marshall Airport Runway Relocation.July 1998.
Alaska Native Tribal Health Consortium (ANTHC) Division of Environmental Health and
Engineering.Marshall, Alaska Heat Recovery Study. July 16, 2012.
Alaska Department of Fish & Game (ADF&G). Wildlife Action Plan Section IIIB: Alaskas 32
Ecoregions
http://www.adfg.alaska.gov/static/species/wildlife_action_plan/section3b.pdf. Last
accessed on September 6, 2012.
ADF&G. Anadromous Waters Catalog.http://www.adfg.alaska.gov/sf/SARR/AWC/. Last
accessed on September 6, 2012.
Alaska Village Marshall Wind Project
Electric Cooperative Concept Design Report
20
ADF&G. 2012c. Refuges, Sanctuaries, Critical Habitat Areas and Wildlife Refuges.
http://www.adfg.alaska.gov/index.cfm?adfg=protectedareas.locator. Last accessed on
September 7, 2012.
ADNR. 2012. Division of Special Management Lands.
http://www.navmaps.alaska.gov/specialmanagementlands/. Last accessed on
September 7, 2012.
Alaska Department of Commerce, Community, and Economic Development; Division of
Community and Regional Affairs.Marshall Area Use Map. 2006.
FAA. Obstruction Evaluation/Airport Airspace Analysis (OE/AAA).
https://oeaaa.faa.gov/oeaaa/external/portal.jsp012. Last accessed on August 26, 2012.
USACE.Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Alaska
Region (Version 2.0).
http://www.usace.army.mil/Portals/2/docs/civilworks/regulatory/reg_supp/erdc el_tr
07 24.pdf. Last accessed on September 6, 2012.
USFWS.United States Fish and Wildlife Service Endangered Species: Listed and Candidate
Species in Alaska, Spectacled Eider (Somateria fischeri).
http://alaska.fws.gov/fisheries/endangered/species/spectacled_eider.htm. Last
accessed on September 6, 2012.
USFWS. Yukon Delta National Wildlife Refuge.
http://www.fws.gov/refuges/profiles/index.cfm?id=74540. Last accessed on September
6, 2012.
USFWS.U.S. Fish and Wildlife Service Land Clearing Guidance for Alaska: Recommended Time
Periods to Avoid Vegetation Clearing.
http://alaska.fws.gov/fisheries/fieldoffice/anchorage/pdf/vegetation_clearing.pdf. Last
accessed on September 7, 2012.
USFWS.U.S. Fish and Wildlife Service National Wetlands Inventory.
http://107.20.228.18/Wetlands/WetlandsMapper.html#. Last accessed on September 6,
2012.
V3 Energy.Marshall Wind Diesel Feasibility Study.September 14, 2012.
Northern Economics.Proposed Wind Project in Marshall: Economic Evaluation Report.
September 17, 2012.
Appendix A
V3 Energys October 2013 Marshall Wind Diesel
Feasibility
Marshall Wind-Diesel Feasibility Analysis
October 7, 2013
Douglas Vaught, P.E.
dvaught@v3energy.com
V3 Energy, LLC
Eagle River, Alaska
Marshall Wind-Diesel Feasibility Analysis P a g e | i
This report was prepared by V3 Energy, LLC under contract to Alaska Village Electric Cooperative to
assess the technical and economic feasibility of installing wind turbines in Marshall. This analysis is part
of a conceptual design project funded in Round IV of the Renewable Energy Fund administered by the
Alaska Energy Authority.
Contents
Introduction..................................................................................................................................................1
Village of Marshall ....................................................................................................................................1
Wind Resource..............................................................................................................................................2
Measured Wind Speeds............................................................................................................................4
Wind Roses................................................................................................................................................4
Wind Frequency Rose...........................................................................................................................5
Total Value (power density) Rose.........................................................................................................5
Wind-Diesel Hybrid System Overview ..........................................................................................................5
Low Penetration Configuration.................................................................................................................6
Medium Penetration Configuration..........................................................................................................6
High Penetration Configuration................................................................................................................7
Wind-Diesel System Components.............................................................................................................8
Wind Turbine(s) ....................................................................................................................................8
Supervisory Control System..................................................................................................................8
Synchronous Condenser .......................................................................................................................8
Secondary Load.....................................................................................................................................9
Deferrable Load ....................................................................................................................................9
Interruptible Load...............................................................................................................................10
Storage Options ..................................................................................................................................10
Wind Turbine Options.................................................................................................................................11
Northern Power Systems NPS100-21 ARCTIC.........................................................................................11
Vestas V20...............................................................................................................................................12
Aeronautica AW33-225...........................................................................................................................12
Homer Software Wind-Diesel Model..............................................................................................................13
Diesel Power Plant..................................................................................................................................13
Wind Turbines.........................................................................................................................................13
Marshall Wind-Diesel Feasibility Analysis P a g e | ii
Electric Load............................................................................................................................................14
Thermal Load ..........................................................................................................................................15
Diesel Generators ...................................................................................................................................15
Economic Analysis.......................................................................................................................................16
Wind Turbine Costs.................................................................................................................................16
Fuel Cost..................................................................................................................................................17
Modeling Assumptions ...........................................................................................................................17
Conclusion and Recommendations ............................................................................................................20
Marshall Wind-Diesel Feasibility Analysis P a g e | 1
Introduction
Alaska Village Electric Cooperative (AVEC) is the electric utility for the City of Marshall. AVEC was
awarded a grant from the Alaska Energy Authority (AEA) to complete feasibility work for installation of
wind turbines, with planned construction in 2015.
Village of Marshall
Marshall is located on the north bank of Polte Slough, north of Arbor Island, on the east bank of the
Yukon River in the Yukon-Kuskokwim Delta. It lies on the northeastern boundary of the Yukon Delta
National Wildlife Refuge. The climate of Marshall is maritime with temperatures ranging between -54
and 86 °F. Average annual rainfall measures 16 inches. Heavy winds in the fall and winter often limit air
accessibility. The Lower Yukon is ice-free from
mid-June through October.
An expedition came upon an Eskimo village called
"Uglovaia" at this site in 1880. Gold was
discovered on nearby Wilson Creek in 1913.
"Fortuna Ledge" became a placer mining camp,
named after the first child born at the camp,
Fortuna Hunter. Its location on a channel of the
Yukon River was convenient for riverboat
landings. A post office was established in 1915,
and the population grew to over 1,000. Later, the
village was named for Thomas Riley Marshall,
Vice President of the United States under Woodrow Wilson from 1913-21. The community became
known as "Marshall's Landing." When the village incorporated as a second-class city in 1970, it was
named Fortuna Ledge but was commonly referred to as Marshall. The name was officially changed to
Marshall in 1984.
A federally-recognized tribe is located in the community -- the Native Village of Marshall. Marshall is a
traditional Yup'ik Eskimo village. Subsistence and fishing-related activities support most residents.
Members of the Village of Ohogamiut also live in Marshall. The sale, importation, and possession of
alcohol are banned in the village.
According to Census 2010, there were 108 housing units in the community and 100 were occupied. Its
population was 94.7 percent American Indian or Alaska Native; 2.7 percent white; 0.2 percent Asian; 2.4
percent of the local residents had multi-racial backgrounds. Additionally, 0.2 percent of the population
was of Hispanic descent.
Water is derived from five wells. Approximately 70% of the city (60 homes) is served by a piped
circulating water and sewer system and has full plumbing. The remainder of the city must haul water
and use honey buckets. An unpermitted landfill is available, and the city has a refuse collection service.
Electricity is provided by Alaska Village Electric Cooperative. There is one school located in the
Marshall Wind-Diesel Feasibility Analysis P a g e | 2
community, attended by 133 students. Local hospitals or health clinics include Agnes Boliver Health
Clinic (Marshall). Emergency Services have river and air access. Emergency service is provided by a
health aide.
Marshall has a seasonal economy with most activity during the summer. Fishing, fish processing, and
BLM firefighting positions are available seasonally. In 2010, 39 residents held commercial fishing
permits. Subsistence activities supplement income. Salmon, moose, bear, and waterfowl are harvested.
Trapping provides some income.
No roads connect Marshall to other communities, so access to Marshall is primarily by air or water. The
city has a State-owned 3,201' long by 100' wide gravel airstrip. The community is also serviced by barge.
Many residents have boats and in winter they rely on snow machines and dog teams for travel.
Wind Resource
A met tower was installed at the proposed wind turbine site in Marshall on December 18, 2008 and was
in continuous operation until October 10, 2009 when an anchor failed during a wind storm and the
tower collapsed. The met tower was replaced in September 2012 and is presently operational. With the
data through September 2013, a mean annual wind speed of 6.27 m/s was measured, with a mean
annual wind power density of 396 W/m
2. This indicates a Class 4 (good) wind resource.
Other aspects of the wind resource also are promising for wind power development. By IEC 61400-1,
3rd edition classification, Marshall is category II to III-C, indicating low turbulence (mean TI at 15 m/s =
0.090) and a moderate probability of extreme wind events. The latter measure is somewhat difficult to
quantify with only 24 months of data, but the site clearly is not energetic enough to be IEC Class I. All
three wind turbines profiled in this report are certified for IEC Class II conditions.
Marshall met tower data synopsis
Data start date December 18, 2008
Data end date Operational (data gap from Oct. 2009 to Sept. 2012);
data thru September 26, 2013 for analysis
Wind power class (by WPD) Class 4 (good)
Wind speed average (30 meters) 6.27 m/s measured
IEC 61400-1 3rd ed. extreme winds Class II/III (note: 23 months data)
Wind power density (30 meters) 396 W/m
2
Weibull distribution parameters k = 1.60, c = 6.8 m/s
Roughness Class 0.77 (rough pasture)
Power law exponent 0.133 (low wind shear)
Frequency of calms (4.0 m/s threshold) 34%
Mean Turbulence Intensity 0.090 (IEC 61400-1 3
rd ed. turbulence category C)
Marshall Wind-Diesel Feasibility Analysis P a g e | 3
Topographic map
Google Earth image
Marshall Wind-Diesel Feasibility Analysis P a g e | 4
Measured Wind Speeds
Measured wind speeds in Marshall are excellent for an inland site and very promising for wind power
development.
Wind Speed Sensor Summary
Variable
Speed 30 m
A
Speed 30 m
B
Speed 22
m
Measurement height (m) 30 30 22
Mean wind speed (m/s) 6.11 6.15 5.90
MoMM wind speed (m/s) 6.23 6.27 6.01
Max 10-min wind speed (m/s) 26.7 30.8 26.6
Weibull k 1.61 1.57 1.57
Weibull c (m/s) 6.81 6.82 6.55
Mean power density (W/m²) 359 378 331
MoMM power density (W/m²) 376 396 345
Mean energy content (kWh/m²/yr) 3,146 3,311 2,896
MoMM energy content (kWh/m²/yr) 3,296 3,471 3,025
Energy pattern factor 2.41 2.51 2.47
Frequency of calms (%) 35.1 35.9 37.3
Marshall Wind speed graph
Wind Roses
Winds at the Marshall met tower test site are primarily east-northeast, north-northwest with occasional
winds from south-southeast (wind frequency rose), with the strongest winds east-northeast (mean value
rose). The power density rose indicates that the power producing winds at the site are predominately
east-northeast. Multiple wind turbines should oriented an axis north-northeast to south-southwest to
provide good exposure to ENE and SSE winds and avoid tower shadowing.
Marshall Wind-Diesel Feasibility Analysis P a g e | 5
Note that a wind threshold of 4.0 m/s was selected for the definition of calm winds. With this threshold,
the Marshall met tower site experienced 34 percent calm conditions during the test period.
Wind Frequency Rose Total Value (power density) Rose
Wind-Diesel Hybrid System Overview
Wind-diesel power systems are categorized based on their average penetration levels, or the overall
proportion of wind-generated electricity compared to the total amount of electrical energy generated.
Commonly used categories of wind-diesel penetration levels are low penetration, medium penetration,
and high penetration. The wind penetration level is roughly equivalent to the amount of diesel fuel
displaced by wind power. Note however that the higher the level of wind penetration, the more
complex and expensive a control system and demand-management strategy is required.
Categories of wind-diesel penetrationlevels
Penetration
Category
Wind Penetration Level
Operating Characteristics and System Requirements
Instantaneous Average
Very Low <60% <8%Diesel generator(s) runs full time
Wind power reduces net load on diesel
All wind energy serves primary load
No supervisory control system
Low 60 to 120% 8 to 20%Diesel generator(s) runs full time
At high wind power levels, secondary loads are
dispatched to insure sufficient diesel loading, or wind
generation is curtailed
Relatively simple control system
Medium 120 to 300% 20 to 50%Diesel generator(s) runs full time
At medium to high wind power levels, secondary
loads are dispatched to insure sufficient diesel
loading
At high wind power levels, complex secondary load
Marshall Wind-Diesel Feasibility Analysis P a g e | 6
Penetration
Category
Wind Penetration Level
Operating Characteristics and System Requirements
Instantaneous Average
control system is needed to ensure heat loads do not
become saturated
Sophisticated control system
High
(Diesels-off
Capable)
300+% 50 to 150%At high wind power levels, diesel generator(s) may be
shut down for diesels-off capability
Auxiliary components required to regulate voltage
and frequency
Sophisticated control system
Low Penetration Configuration
Low-penetration wind-diesel systems require the fewest modifications to a new or existing power
system in that maximum wind penetration is never sufficient to present potential electrical stability
problems. But, low penetration wind systems tend to be less economical than higher penetration
systems due to the limited annual fuel savings compared to a relatively high total wind system
installation costs. This latter point is because all of the fixed costs of a wind power project – equipment
mobilization and demobilization, distribution connection, new road access, permitting, land acquisition,
etc. – are spread across fewer turbines, resulting in relatively high per kW installed costs.
Medium Penetration Configuration
Medium penetration mode is very similar to high penetration mode except that no electrical storage is
employed in the system and wind capacity is designed for a moderate and usable amount of excess wind
energy that must be diverted to thermal loads. All of AVEC’s modern wind power systems are designed
as medium penetration systems.
Marshall Wind-Diesel Feasibility Analysis P a g e | 7
High Penetration Configuration
Other communities, such as Kokhanok, are more aggressively seeking to offset diesel used for thermal
and electrical energy. They are using configurations which will allow for the generator sets to be turned
off and use a significant portion of the wind energy for various heating loads. The potential benefit of
these systems is the highest, however currently the commissioning for these system types due to the
increased complexity, can take longer.
Marshall Wind-Diesel Feasibility Analysis P a g e | 8
Wind-Diesel System Components
Listed below are the main components of a medium to high-penetration wind-diesel system:
Wind turbine , plus tower and foundation
Supervisory control system
Synchronous condenser
Secondary load
Deferrable load
Interruptible load
Storage
Wind Turbine(s)
Village-scale wind turbines are generally considered as 50 kW to 250 kW rated output. This turbine size
once dominated with worldwide wind power industry but has been left behind in favor of much larger
1,000 kW plus capacity turbines for utility grid-connected projects. Conversely, many turbines are
manufactured for home or farm application, but generally these are 10 kW or smaller. Consequently,
few new manufacture village size-class turbines are on the market, although a large supply of used
and/or remanufactured turbines are available. The latter typically result from the repower of older wind
farms in the Continental United States and Europe with new, larger wind turbines.
Supervisory Control System
Medium- and high-penetration wind-diesel systems require fast-acting real and reactive power
management to compensate for rapid variation in village load and wind turbine power output. A wind-
diesel system master controller, also called a supervisory controller, would be installed inside the
existing Marshall power plant or in a new module adjacent to it. The supervisory controller would select
the optimum system configuration based on village electric load demand and available wind power.
Synchronous Condenser
A synchronous condenser, sometimes called a synchronous compensator, is a specialized synchronous
electric motor with an output shaft that spins freely. Its excitation field is controlled by a voltage
regulator to either generate or absorb reactive power as needed to support the grid voltage or to
maintain the grid power factor at a specified level. This is necessary for diesels-off wind turbine
operations, but generally not required for wind systems that maintain a relatively large output diesel
generator online at all times.
Marshall Wind-Diesel Feasibility Analysis P a g e | 9
Synchronous condenser in Kokhanok
Secondary Load
To avoid curtailing wind turbines during periods of high wind/low load demand, a secondary or “dump”
load is installed to absorb excess system (principally wind) power beyond that required to meet the
electrical load. The secondary load converts excess wind energy into heat via an electric boiler typically
installed in the diesel generator heat recovery loop. This heat can be for use in space and water heating
through the extremely rapid (sub-cycle) switching of heating elements, such as an electric boiler
imbedded in the diesel generator jacket water heat recovery loop. As seen in Figure 16, a secondary
load controller serves to stabilize system frequency by providing a fast responding load when gusting
wind creates system instability.
An electric boiler is a common secondary load device used in wind-diesel power systems. An electric
boiler (or boilers), coupled with a boiler grid interface control system, in a new module outside the
Marshall power plant building, would be sized to absorb up to 200 kW of instantaneous energy (full
output of the wind turbines). The grid interface monitors and maintains the temperature of the electric
hot water tank and establishes a power setpoint. The wind-diesel system master controller assigns the
setpoint based on the amount of unused wind power available in the system. Frequency stabilization is
another advantage that can be controlled with an electric boiler load. The boiler grid interface will
automatically adjust the amount of power it is drawing to maintain system frequency within acceptable
limits.
Deferrable Load
A deferrable load is electric load that must be met within some time period, but exact timing is not
important. Loads are normally classified as deferrable because they have some storage associated with
them. Water pumping is a common example - there is some flexibility as to when the pump actually
operates, provided the water tank does not run dry. Other examples include ice making and battery
charging. A deferrable load operates second in priority to the primary load and has priority over
charging batteries, should the system employ batteries as a storage option.
Marshall Wind-Diesel Feasibility Analysis P a g e | 10
Interruptible Load
Electric heating either in the form of electric space heaters or electric water boilers should be explored
as a means of displacing stove oil with wind-generated electricity. It must be emphasized that electric
heating is only economically viable with excess electricity generated by a renewable energy source such
as wind and not from diesel-generated power. It is typically assumed that 41 kWh of electric heat is
equivalent to one gallon of heating fuel oil.
Storage Options
Electrical energy storage provides a means of storing wind generated power during periods of high
winds and then releasing the power as winds subside. Energy storage has a similar function to a
secondary load but the stored, excess wind energy can be converted back to electric power at a later
time. There is an efficiency loss with the conversion of power to storage and out of storage. The
descriptions below are informative but are not currently part of the overall system design.
Batteries
Battery storage is a generally well-proven technology and has been used in Alaskan power systems
including Fairbanks (Golden Valley Electric Association), Wales and Kokhanok, but with mixed results in
the smaller communities. Batteries are most appropriate for providing medium-term energy storage to
allow a transition, or bridge, between the variable output of wind turbines and diesel generation. This
“bridging” period is typically 5 to 15 minutes long. Storage for several hours or days is also possible with
batteries, but this requires higher capacity and cost. In general, the disadvantages of batteries for utility-
scale energy storage, even for small utility systems, are high capital and maintenance costs and limited
lifetime. Of particular concern to rural Alaska communities is that batteries are heavy and expensive ship
and most contain hazardous substances that require special removal from the village at end of service
life and disposal in specially-equipped recycling centers.
There are a wide variety of battery types with different operating characteristics. Advanced lead acid
and zinc-bromide flow batteries were identified as “technologically simple” energy storage options
appropriate for rural Alaska in an Alaska Center for Energy and Power (ACEP) July, 2009 report on
energy storage. Nickel-cadmium (NiCad) batteries have been used in rural Alaska applications such as
the Wales wind-diesel system. Advantages of NiCad batteries compared to lead-acid batteries include a
deeper discharge capability, lighter weight, higher energy density, a constant output voltage, and much
better performance during cold temperatures. However, NiCads are considerably more expensive than
lead-acid batteries and one must note that the Wales wind-diesel system had a poor operational history
and has not been functional for over ten years.
Because batteries operate on direct current (DC), a converter is required to charge or discharge when
connected to an alternating current (AC) system. A typical battery storage system would include a bank
of batteries and a power conversion device. The batteries would be wired for a nominal voltage of
roughly 300 volts. Individual battery voltages on a large scale system are typically 1.2 volts DC. Recent
advances in power electronics have made solid state inverter/converter systems cost effective and
preferable a power conversion device. The Kokhanok wind-diesel system is designed with a 300 volts DC
battery bank coupled to a grid-forming power converter for production of utility-grade real and reactive
Marshall Wind-Diesel Feasibility Analysis P a g e | 11
power. Following some design and commissioning delays, the solid state converter system in Kokhanok
should be operational by late 2013 and will be monitored closely for reliability and effectiveness.
Wind Turbine Options
Several village-scale wind turbines are considered suitable for Marshall. The guiding criteria are turbine
output rating in relation to electric load, simplicity of design, AVEC Operations department preferences,
redundancy, and cost considerations. The turbines chose for review in this CDR are the Northern Power
Systems NPS 100, the Vestas V20, and the Aeronautica 33-225.
Northern Power Systems NPS100-21 ARCTIC
The Northern Power 100-21 ARCTIC (NPS100-21), formerly known as the Northwind 100 (NW100), is
rated at 100 kW and is equipped with a permanent magnet, synchronous generator, is direct drive (no
gearbox), can be equipped with heaters and insulation, and has been tested to ensure operation in
extreme cold climates. The turbine has a 21 meter diameter rotor and is available with a 30 or 37 meter
monopole towers, or a 48 meter lattice tower. The rotor blades are fixed pitch for stall control but the
turbine is also inverter regulated for maximum 100 kW power output. For Marshall, the NPS100-21 will
be equipped with a cold climate package enabling a minimum operating temperature of -40° C. The
Northern Power 100 is the most widely represented village-scale wind turbine in Alaska with a
significant number of installations in the Yukon-Kuskokwim Delta and on St. Lawrence Island. The
Northern Power 100-21 wind turbine is manufactured in Barre, Vermont, USA. More information may
be found at http://www.northernpower.com/.
Northern Power NPS100 wind turbine
Marshall Wind-Diesel Feasibility Analysis P a g e | 12
Vestas V20
The Vestas V20 was originally manufactured by Vestas Wind Systems A/S in Denmark and is no longer in
production. It is, however, available as a remanufactured unit from Halus Power Systems in California
(represented in Alaska by Marsh Creek, LLC) and from Talk, Inc. in Minnesota. The V20 is rated at 120
kW and is a higher output version of the two Vestas V17 wind turbines installed in Kokhanok in 2011.
The V20 has a fixed-pitch, stall-regulated rotor coupled to an asynchronous (induction) generator via a
gearbox drive. The original turbine design included low speed and high speed generators in order to
optimize performance at low and high wind speeds. The two generators are connected to the gearbox
with belt drives and a clutch mechanism. In some installations though – especially sites with a high
mean wind speeds – the low speed generator is removed to eliminate a potential failure point.
Vestas V17 wind turbines in Kokhanok (similar to the V20)
Aeronautica AW33-225
The Aeronautica AW33-225 wind turbine is manufactured new by Aeronautica in Durham, New
Hampshire. This turbine was originally designed by the Danish-manufacturer Norwin in the 1980’s with
a 29 meter rotor diameter and had a long and successful history in the wind industry before being
replaced by larger capacity turbines for utility-scale grid-connect installations. The original 29 meter
rotor diameter design is available as the AW29-225 for IEC Class IA wind regimes. The AW33-225 is a
new variant designed for IEC Class II and III winds. The AW225 turbine is stall-regulated, has a
synchronous (induction) generator, active yaw control, is rated at 225 kW power output, and is available
with 30, 40, or 50 meter tubular steel towers. The AW33-225 is cold climate certified to -30° C and is
new to the Alaska market with no in-state installations at present. While the AW29-225 has a typical
cut-out wind speed of 25 m/s, the larger rotor diameter AW33-225 is designed for a cut-out speed of 22
m/s. More information can be found at http://aeronauticawind.com/aw/index.html.
Marshall Wind-Diesel Feasibility Analysis P a g e | 13
Aeronautica AW 33-225 wind turbine (29-225 version shown)
Homer Software Wind-Diesel Model
Homer energy modeling software was used to analyze the existing Marshall power plant. Homer
software was designed to analyze hybrid power systems that contain a mix of conventional and
renewable energy sources, such as diesel generators, wind turbines, solar panels, batteries, etc. and is
widely used to aid development of Alaska village wind power projects. It is a static energy balance
model, however, and is not designed to model the dynamic stability of a wind-diesel power system,
although it will provide a warning that renewable energy input is potential sufficient to result in system
instability.
Diesel Power Plant
Electric power (comprised of the diesel power plant and the electric power distribution system) in
Marshall is provided by AVEC with the following diesel configuration.
Marshall powerplantdiesel generators
Generator Electrical Capacity Diesel Engine Model Generator
1 500 kW Caterpillar 3456 Cat LC6
2 363 kW Detroit Series 60 DDEC4 Kato 6P4-1450
3 236 kW Detroit Series 60 DDEC4 Kato 6P4-1450
Wind Turbines
This CDR evaluates installation of three new Northern Power Systems NPS100-21 turbines for 300 kW
installed capacity, three remanufactured Vestas V20 turbines for 360 kW installed capacity, or one new
Aeronautica AW33-225 turbines for 225 KW installed capacity. Standard temperature and pressure
(STP) power curves are shown below. Note that for the Homer analysis, site elevation was adjusted to
reflect the measured mean annual air density of 1.294 kg/m3.
Marshall Wind-Diesel Feasibility Analysis P a g e | 14
Northern Power 100-24 Arctic Vestas V20
Aeronautica AW33-225
Electric Load
Marshall electric load data, collected from March 2012 to September 2013, was received from William
Thompson of AVEC. These data are in 15 minute increments and represent total electric load demand
during each time step. The data were processed by adjusting the date/time stamps nine hours from
UTC to Yukon/Alaska time, converting the data from kWh to kW, and creating a January 1 to December
31 hourly list for export to HOMER software. The resulting load is shown graphically below. Average
load is 190 kW with a 323 kW peak load and an average daily load demand of 4,561 kWh. This compares
to a 185 kW average load reported to the RCA for the 2012 PCE report.
Electric load
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann
50
100
150
200
250
300
350 Seasonal Profile
max
daily high
mean
daily low
min
Marshall Wind-Diesel Feasibility Analysis P a g e | 15
Thermal Load
Powerplant heat recovery in Marshall is non-functional at present with fairly long distances to relatively
large heat loads. Homer modeling indicates that excess wind energy from the wind turbine
combinations considered would be large enough to warrant construction of a recovered heat system or
remote placement of a secondary load controller/electric boiler in a building with high thermal demand,
such as the new school or the water plant. Due to the relatively modest amount of predicted excess
energy from wind turbine operation, it is assumed that the school and/or water plant can use this excess
energy to displace heating oil usage.
Diesel Generators
The HOMER model was constructed with all three Marshall diesel generators. For cost modeling
purposes, AEA assumes a generator O&M cost of $0.020/kWh. Other diesel generator information
pertinent to the HOMER model is shown below. Individual generator fuel curve information is available
but Homer modeling with generator-specific fuel curves indicated fuel efficiency of 15.3 kWh/gal in the
base case (no wind turbines). This is higher than AVEC’s reported fuel efficiency of 12.98 kWh/gal to
Regulatory Commission of Alaska for the 2012 Power Cost Equalization Report, and the 14.44 kWh/gal
efficiency for Marshall documented in AVEC’s 2011 annual generation report.
Diesel generator HOMER modeling information
Diesel generator Caterpillar
3456
Detroit Series
60 DDEC4
Detroit Series
60 DDEC4
Power output (kW) 500 363 236
Intercept coeff. (L/hr/kW
rated)
0.00651 0.0195 0.0146
Slope (L/hr/kW output) 0.2382 0.2122 0.2384
Minimum electric
load (%)
5.0%
(25 kW)
6.9%
(25 kW)
10.6%
(25 kW)
Heat recovery ratio (% of
waste heat that can serve
the thermal load)
22 22 22
Intercept coefficient – the no-load fuel consumption of the generator divided by its capacity
Slope – the marginal fuel consumption of the generator
0 6 12 18 24
0
50
100
150
200
250 Daily Profile
Hour Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
0
6
12
18
24 DMap
90
138
186
234
282
330
kW
Marshall Wind-Diesel Feasibility Analysis P a g e | 16
Cat 3456 fuel efficiency curve DD60 DDEC4 Gen 2
DD60 DDEC4 Gen 3
Economic Analysis
Installation of wind turbines in medium penetration mode is evaluated in this report to demonstrate the
economic impact of these turbines with the following configuration: turbines are connected to the
electrical distribution system with first priority to serve the electrical load, and second priority to serve
the thermal load via a secondary load controller and electric boiler.
Wind Turbine Costs
Project capital and construction costs for the three evaluated wind turbines were obtained from HDL,
Inc. and are presented below. Detailed information regarding HDL’s cost estimates is available in their
portion of this conceptual design report.
Project cost estimates
Turbine
No.
Turbines
HDL
Estimated
Project Cost
Installed
kW
Cost per kW
Capacity Tower Type
Tower
Height
(meters)
Northern Power
NPS100-21 Arctic 3 $3,441,275 285 $12,074 Monopole 37
Vestas V20 3 $3,102,175 360 $8,617 Lattice 32
Aeronautica
AW33-225 1 $2,808,025 225 $12,480 Monopole 50
Marshall Wind-Diesel Feasibility Analysis P a g e | 17
Fuel Cost
A fuel price of $4.99/gallon ($1.32/Liter) was chosen for the initial HOMER analysis by reference to
Alaska Fuel Price Projections 2013-2035, prepared for Alaska Energy Authority by the Institute for Social
and Economic Research (ISER), dated June 30, 2013 and the 2013_06_R7Prototype_final_07012013
Excel spreadsheet, also written by ISER. The $4.99/gallon price reflects the average value of all fuel
prices between the 2015 (the assumed project start year) fuel price of $4.17/gallon and the 2034 (20
year project end year) fuel price of $5.98/gallon using the medium price projection analysis with an
average social cost of carbon (SCC) of $0.61/gallon included.
By comparison, the fuel price for Marshall (without social cost of carbon) reported to Regulatory
Commission of Alaska for the 2012 PCE report is $3.32/gallon ($0.88/Liter), without inclusion of the SCC.
Assuming an SCC of $0.40/gallon (ISER Prototype spreadsheet, 2013 value), the Marshall’s 2012 diesel
fuel price was $3.72/gallon ($0.98/Liter).
Heating fuel displacement by excess energy diverted to thermal loads is valued at $6.32/gallon
($1.67/Liter) as an average price for the 20 year project period. This price was determined by reference
to the 2013_06_R7Prototype_final_07012013 Excel spreadsheet where heating oil is valued at the cost
of diesel fuel (with SCC) plus $1.05/gallon, assuming heating oil displacement between 1,000 and 25,000
gallons per year.
Fuel cost table (SCC included)
ISER med.
projection 2015 (/gal) 2034 (/gal)
Average
(/gallon)
Average
(/Liter)
Diesel Fuel $4.17 $5.98
$4.99 $1.32
Heating Oil $5.22 $7.03
$6.04 $1.60
Modeling Assumptions
As noted previously, HOMER energy modeling software was used to analyze a wind-diesel hybrid power
plant to serve Marshall. HOMER is designed to analyze hybrid power systems that contain a mix of
conventional and renewable energy sources, such as diesel generators, wind turbines, solar panels,
batteries, etc. and is widely used to aid development of Alaska village wind power projects.
Modeling assumptions are detailed in the table below. Assumptions such as project life, discount rate,
operations and maintenance (O&M) costs, etc. are AEA default values and contained in the ISER
spreadsheet model. Other assumptions, such as diesel overhaul cost and time between overhaul are
based on general rural Alaska power generation experience.
The base or comparison scenario is the existing power plant with no functional heat recovery loop. Note
that wind turbines installed in Marshall will operate in parallel with the diesel generators. Excess energy
will serve thermal loads via a secondary load controller and electric boiler (to be installed). Installation
cost of wind turbines assumes construction of three phase power distribution to the selected site, plus
civil, permitting, integration and other related project costs.
Marshall Wind-Diesel Feasibility Analysis P a g e | 18
Homer modeling assumptions
Economic Assumptions
Project life 20 years (2015 to 2034)
Discount rate 3%
Operating Reserves
Load in current time step 10%
Wind power output 100% (Homer setting to always force diesels on)
Fuel Properties (no. 2 diesel for
powerplant)
Heating value 46.8 MJ/kg (140,000 BTU/gal)
Density 830 kg/m
3 (6.93 lb./gal)
Price (20 year average; ISER 2013,
medium projection plus social cost of
carbon)
$4.99/gal ($1.32/Liter)
Fuel Properties (no. 1 diesel to serve
thermal loads)
Heating value 44.8 MJ/kg (134,000 BTU/gal)
Density 830 kg/m
3 (6.93 lb./gal)
Price (20 year average; ISER 2013,
medium projection plus social cost of
carbon)
$6.04/gal ($1.60/Liter)
Diesel Generators
Generator capital cost $0 (new generators already funded)
O&M cost $0.02/kWh (reference: ISER 2013 Prototype spreadsheet)
Diesel generator efficiency (Homer) 15.2 kWh/gal (from diesel fuel curves)
Diesel generator efficiency (ISER) 13.0 kWh/gal (from 2012 PCE report)
Minimum load 25 kW; based on AVEC’s operational criteria of 25 kW
minimum diesel loading with their wind-diesel systems
Schedule Optimized
Wind Turbines
Availability 80%
O&M cost $0.049/kWh (reference: ISER 2013 Prototype spreadsheet)
Wind speed 6.27 m/s at 30 m, 100% turbine availability
5.57 m/s at 30 m, 80% turbine availability
Density adjustment 1.242 kg/m^3 (mean of monthly means of 18 months of
Marshall met tower data; Homer wind resource elevation set
at -150 meters to simulate the Marshall air density
Power law exponent 0.133 (met tower data)
Hub height/tower type NPS100-21 Arctic: 37 meter monopole
V20: 32 meter lattice
AW33-225: 50 meter monopole
Energy Loads
Electric 4.56 MWh/day average Marshall power plant load
Thermal Undefined at present; assumed large enough to absorb excess
wind energy
Marshall Wind-Diesel Feasibility Analysis P a g e | 20
Conclusion and Recommendations
Marshall has a very good wind resource for wind power development, especially considering its distance
from the Bering Sea coast. Wind behavior is desirable with low turbulence, low wind shear, moderate
extreme wind probability, and little evidence of severe icing conditions.
The analysis in this report considered configurations of three Northern Power 100 wind turbines, three
remanufactured Vestas V20 wind turbines, or one Aeronautica AW225 wind turbine, all in a medium
penetration configuration with no electrical storage and a wind-heat node at the school or the water
plant.
It is recommended that this project proceed to the design phase. Further analysis and discussion may
better highlight advantages and disadvantages of each option considered, but at present all three
options present nearly equivalent economic valuation, hence turbine choice is largely a matter of
preference for the utility.
Appendix B
ANTHC Marshall Alaska Heat Recovery Study
Appendix C
August 3, 2012 Marshall Wind Site Investigation
Report
Marshall WAsP Site Options Analysis
July 23, 2012
Using ten months of wind data collected from the Marshall met tower (Site 0050), WAsP software was
used to model the wind regime of Marshall and to predict mean wind speed and turbine performance at
the met tower site and three possible alternative wind power sites, shown in the maps below.
Topographic maps
Google Earth map
WAsP wind speed map
Predicted site wind speed and turbine performance
Wind speed and turbine annual energy production (AEP) are calculated by the WAsP software. Turbine
AEP is based on the NW100B turbine at a 30 meter hub height, the height of the met tower upper level
anemometers. Turbine hub height is 37 meters, hence actual turbine AEP would be better than
indicated below, but setting turbine hub height at anemometer height simplifies the analysis and the
purpose here is comparative, not actual. Once a site is chosen and the CDR written, turbine type and
actual hub height will be adjusted to obtain true predicted performance.
Site comparison table
Mean
wind
speed
Mean
power
density AEP
AEP
compared
to met
tower site
m/s W/m² MWh/yr %
Met tower site 6.19 336 239.5 100%
Alternate Site 1 6.44 388 255.7 107%
Alternate Site 2 6.09 330 231.9 97%
Alternate Site 3 6.72 441 274.2 114%
Recommendation
The wind site options in Marshall, in a general sense, are good considering Marshall’s distance upriver
from the coast. The met tower site is roughly comparable to alternate site 2, but nearby alternate site 1,
just 315 meters straight downhill from the met tower site toward the Yukon River, is predicted at 7
percent higher energy production. Alternate site 3, located on a rise on the road leading to the UUI
tower on Pilcher Mountain, is the best of the four sites with predicted 14 percent higher turbine energy
production than at the met tower site.
It is recommended that all four possible wind sites be investigated for landownership and access issues.
Distribution line construction costs should be compared to turbine performance over time to determine
highest net present value; this will help determine the preferred turbine site for development.
H:\jobs\12-025 Marshall Wind Project\Site Visit 8-3-12\PHOTOLOG.docx Page 1 Photo 1: Met Tower Site Photo 2: Seasonal Access Road to Alternative Sites 2 and 3 Photo 3: Existing UUI Communication Pole Settlement Photo 4: Access Road to Airport, between Marshall and Wilson Creek
H:\jobs\12-025 Marshall Wind Project\Site Visit 8-3-12\PHOTOLOG.docx Page 2 Photo 5: Native Allotment near Alternative Site 1 Photo 6: Inside Existing AVEC Power Plant
Appendix D
Marshall Wind Project Feasibility Design Drawings
MARSHALL WIND PROJECTMARSHALLFEASIBILITY DESIGN DRAWINGSMARSHALL, ALASKASHEET INDEXNOT FORCONSTRUCTION4831 Eagle StreetAnchorage, Alaska 99503
ABBREVIATIONSLEGENDEARTHWORKTUNDRA PROTECTIONNOT FORCONSTRUCTION4831 Eagle StreetAnchorage, Alaska 99503
NOT FORCONSTRUCTION4831 Eagle StreetAnchorage, Alaska 99503
NOT FORCONSTRUCTION4831 Eagle StreetAnchorage, Alaska 99503
NOT FORCONSTRUCTION4831 Eagle StreetAnchorage, Alaska 99503
NOT FORCONSTRUCTION4831 Eagle StreetAnchorage, Alaska 99503
NOT FORCONSTRUCTION4831 Eagle StreetAnchorage, Alaska 99503
NOT FORCONSTRUCTION4831 Eagle StreetAnchorage, Alaska 99503
Appendix E
Concept Level Capital Cost Estimate
Concept Level EstimateMarshall Wind Farm ConstructionAlternative Cost Summary9/30/13SUMMARYDescription Estimated Construction Installed kW Estimated Construction Tower TypeCost Cost/ Installed kWAlternative 1 - (3) Northern Power 100 Arctic Turbines $ 3,174,175.00 300 $ 10,580.58 MonopoleAlternative 2 - (3) V20's $ 2,890,575.00 360 $ 8,029.38 Lattice Alternative 3- (1) AW33-225 $ 2,660,400.00 225 $ 11,824.00 Monopole
Concept Level Estimate
Marshall Wind Farm Construction
Alternative 1
9/30/13
Item Estimated
Quantity Unit Price ($) Subtotal ($)
Alternative 1 (3) Northern Power 100 Arctic Turbines
1 4,123 CY Borrow 25 103,075
2 24,000 SF Geotextile 2 48,000
3 3 Each Concrete Gravity Mat Foundations 100,000 300,000
4 3 Each Northern Power 100B Arctic Wind Turbines 375,000 1,125,000
5 3,500 LF Electrical Spur Line to New Power Plant Location 37 129,500
6 1 Sum Wireless Communication System 75,000 75,000
7 1 Sum Wind Turbine Power Integration 250,000 250,000
8 1 Sum Labor 130,000 130,000
9 1 Sum Equipment 125,000 125,000
10 1 Sum Freight 450,000 450,000
11 1 Sum Indirects 150,000 150,000
Subtotal Construction 2,885,575$
Land Acquisition $0
Project Contingency @ 10% 288,600$
0 Years Inflation @ 2% $0
Total 3,174,175$
Installed Generation Capacity 300 kW
Total Cost 3,174,175$
Cost/Installed kW $10,581
Description
Concept Level Estimate
Marshall Wind Farm Construction
Alternative 2
9/30/13
Item Estimated
Quantity Unit Price ($) Subtotal ($)
Alternative 2 (3) V20's
1 4,123 CY Borrow 25 103,075
2 24,000 SF Geotextile 2 48,000
3 3 Each Concrete Gravity Mat Foundations 104,000 312,000
4 3 Each Vestas V20 Wind Turbines 225,000 675,000
5 3,100 LF Electrical Spur Line to New Power Plant Location 37 114,700
6 1 Sum Wireless Communication System 75,000 75,000
7 1 Sum Wind Turbine Power Integration 375,000 375,000
8 1 Sum Labor 150,000 175,000
9 1 Sum Equipment 100,000 150,000
10 1 Sum Freight 332,000 400,000
11 1 Sum Indirects 175,000 200,000
Subtotal Construction 2,627,775$
Land Acquisition $0
Project Contingency @ 10% 262,800$
0 Years Inflation @ 2% $0
Total 2,890,575$
Installed Generation Capacity 360 kW
Total Cost 2,890,575$
Cost/Installed kW $8,029
Description
Concept Level Estimate
Marshall Wind Farm Construction
Alternative 3
9/30/13
Item Estimated
Quantity Unit Price ($) Subtotal ($)
Alternative 3 (1) AW33 225
1 1,400 CY Borrow 25 35,000
2 8,000 SF Geotextile 2 16,000
3 1 Each Concrete Gravity Mat Foundations 275,000 275,000
4 1 Each AW33 225 Wind Turbines 600,000 600,000
5 2,500 LF Electrical Spur Line to New Power Plant Location 37 92,500
6 1 Sum Wireless Communication System 75,000 75,000
7 1 Sum Wind Turbine Power Integration 400,000 400,000
8 1 Sum Labor 25,000 175,000
9 1 Sum Equipment 150,000 150,000
10 1 Sum Freight 525,000 400,000
11 1 Sum Indirects 200,000 200,000
Subtotal Construction 2,418,500$
Land Acquisition $0
Project Contingency @ 10% 241,900$
0 Years Inflation @ 2% $0
Total 2,660,400$
Installed Generation Capacity 225 kW
Total Cost 2,660,400$
Cost/Installed kW $11,824
Description
Appendix E
FAA Permitting