HomeMy WebLinkAboutAtmautluak Wind Renewable Energy Project Wind-Diesel Feasibility Study - Sep 2011 - REF Grant 70400021
Atmautluak Wind-Diesel
Feasibility Study
Atmautluak Traditional Council
November 17, 2010
Revised September 30, 2011
WHPacific, Inc.
300 W. 31
st Ave
Anchorage, AK 99503
www.whpacific.com
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Table of Contents
Executive Summary
1. Background Data
2. Site & Powerhouse Assessment
3. Initial Environmental Review
4. System Configuration Options
5.Economic Analysis
6. Development Plan
Appendix A: Atmautluak AEA Wind Energy Resource Report
Appendix B: Atmautluak Site & Powerhouse Field Visit Report
Appendix C: Environmental Review Checklist Memo
Appendix D:HOMER Analysis
Appendix E: Manufacturer-provided Specification Sheets
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Executive Summary
The preliminary economic feasibility analysis by the HOMER software, based on the cost estimates
presented in this report, indicates that Atmautluak very likely would save on energy costs by installing a
wind power generation facility. Detailed cost estimating during the design phase is warranted to
confirm the economic feasibility before a decision should be made to proceed with construction. An
electric boiler heating system could be installed as part of the wind-diesel system to use excess wind
energy,possibly providing supplemental heat to the store, tribal office, washeteria and school.A
battery storage bank should also be incorporated to maximize the wind resource.
The Alaska Energy Authority’s January 2007 wind resource assessment in Atmautluak concluded that the
wind resource was Class 5, or “Excellent”. Based on data collected between October 21, 2005 and
December 4, 2006 from a 30-meter meteorological tower in Atmautluak, the annual average wind speed
recorded was 7.16 m/s (16.0 mph) with north identified as the prevailing wind direction.
It is recommended that Atmautluak’s wind energy be developed as a medium-or high-penetration
system, with two Vestas V17 turbines of 90 kW capacity each or two Northern Power Systems NW100
Arctic turbines of 100 kW capacity each.Preliminary rough order of magnitude (ROM) cost estimates of
these two alternatives are listed below:
$1,725,000 total installed cost for 2-turbine Vestas V17 (180 kW) wind system
$2,325,000 total installed cost for 2-turbine NW100 Arctic (200 kW) wind system
Preliminary estimates of annual diesel fuel savings are over 24,200 gallons for a 180 kW wind system
(42% reduction ), and over 30,500 gallons for a 200 kW wind system (53% reduction).
The benefit/cost ratio for the 2-turbine V17 wind system over the base case (no turbines -$0 fixed
system cost)is estimated at 1.027 over 20 years . The benefit/cost ratio for the 2-turbine NW100
Arctic wind system over the base case is estimated at 1.017.
According to Atmautluak Joint Utilities, the diesel power plant generated 679,129 kWh in 2009, with an
average annual load of 78 kW. The peak load of the Atmautluak system is estimated to be about 150
kW.During 2009, 53,901 gallons of fuel was used for power generation in Atmautluak, at an average
diesel generation efficiency of 12.6 kWh/gallon. The reported pre-subsidy residential cost of electricity
was $0.69860/kWh.The total existing generation capacity is 547 kW, with modern diesel generator sets.
The community’s preferred wind turbine site is located about 0.45 miles northwest of the Atmautluak
power plant, and about 800 feet NW of the location where the met tower was installed. The site is
located entirely on land owned by Atmautluak Limited, the local village corporation.
There are no listed species under the Endangered Species Act (ESA) in the wind project area, so an ESA
consultation with US Fish and Wildlife Service is not necessary, although a consultation is needed under
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the Migratory Bird Treaty Act. Other permits/approvals needed include a Form 7460-1 approval from
the Federal Aviation Administration, a Section 404 permit from the US Army Corps of Engineers, and a
consistency review by the Alaska Department of National Resources for the Coastal Zone Management
Program.Also, the construction contractor needs to submit a Storm Water Pollution Prevention Plan to
the Alaska Department of Environmental Conservation.
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1.Background Data
Atmautluak is located 20 miles northwest of Bethel, on the west bank of the Pitmiktakik River in the
Yukon-Kuskokwim Delta. The population of Atmautluak is 305 people (2000 Census).
Atmautluak Wind Energy Resource
The Alaska Energy Authority’s January 2007 wind resource assessment in Atmautluak, included in
Appendix A,concluded that the wind resource was Class 5, or “Excellent”. Based on data collected
between October 21, 2005 and December 4, 2006 from a 30-meter NRG met tower in Atmautluak, the
annual average wind speed recorded was 7.16 m/s (16.0 mph) with north identified as the prevailing
wind direction.Taking into account the local air density and wind speed distribution, the average wind
power density for the met tower site is 451 W/m
2.The month of highest average reported wind speeds
during this period was February, and the monthwith the lowest average wind speeds was September.
The met tower was located at 60° 51.686’ N, 162° 17.032’W (NAD83 coordinates converted from
NAD27 coordinates in 2007 AEA wind resource report), or about 800 feet southeast from the preferred
wind turbine site (see section 2 below).
Atmautluak Energy Needs
According to Atmautluak Joint Utilities, the diesel power plant generated 679,129 kWh in 2009, with an
average annual load of 78 kW.The peak load of the Atmautluak system is estimated to be about 150
kW.
Monthly generation and fuel consumption statistics for 2009 are presented in Table 1, and average
monthly electric loads for 2009 are graphed in Figure 1.
During 2009,53,901 gallons of fuel was used for power generation in Atmautluak, at an average diesel
generation efficiency of 12.6 kWh/gallon.
The reported pre-subsidy residential cost of electricity was $0.69860/kWh.
The reported retail rate for other fuels in Atmautluak was $5.45/gallon for heating fuel, $5.50/gallon for
gasoline.
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Table 1: Atmautluak Joint Utilities power generation statistics for 2009
Month
#days in
month
kWh
generated
monthly average
load (kW)
fuel used
(gal)
average diesel
efficiency (kWh/gal)
January 31 63,379 85 5,012 12.6
February 28 60,713 90 4,109 14.8
March 31 59,801 80 4,579 13.1
April 30 47,687 66 4,006 11.9
May 31 49,221 66 4,094 12.0
June 30 52,568 73 4,288 12.3
July 31 49,901 67 4,464 11.2
August 31 54,940 74 3,810 14.4
September 30 58,662 81 4,469 13.1
October 31 56,555 76 4,341 13.0
November 30 59,326 82 4,604 12.9
December 31 66,376 89 6,125 10.8
annual 365 679,129 78 53,901 12.6
Figure 1: Average monthly electric load of Atmautluak Joint Utilities for 2009
-
10
20
30
40
50
60
70
80
90
100
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
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2.Site & Powerhouse Assessment
Brian Yanity of WHPacific visited Atmautluak on September 2, 2010 to assess the diesel power
generation system, switchgear and ancillary equipment, as well as inspect possible wind turbine sites.
Atmautluak Joint Utilities staff provided tours of the existing diesel powerhouse, the prospective wind
turbine sites, as well as documentation and drawings. Danie l Waska, Atmautluak Tribal Administrator,
presented a map with potential wind turbine sites identified by the community: a preferred site and an
“alternate” site (see site locations in Figure 2).The complete field visit report, with photos of the wind
sites and powerhouse, is attached as Appendix B.
During the site visit, the wind-diesel project concept, and pending grant proposal to the Alaska Energy
Authority’s Renewable Energy Fund, was presented at a community meeting hosted by the Atmautluak
Traditional Council. At the community meeting, several residents expressed support for wind energy,
saying that a reduction in the community’s overall diesel fuel consumption is highly desired. No
concerns were expressed other than a question about how the state grant funds would be administered.
Atmautluak Joint Utilities-Existing Power System
The cost of fuel purchased by Atmautluak Joint Utilities in 2010 was reported as $3.3688/gallon
(although some fuel purchased for $5.20/gallon was shipped in during the winter of 2010 due to a
temporary fuel shortage). The reported pre-subsidy retail cost of electricity for 2010 is $0.69860/kWh.
The existing three diesel generator sets in the power plant are detailed in Table 2:
Table 2: Atmautluak Joint Utilities existing diesel generators
Genset
#
Capacity Generator Engine
1 180 kW
225 kVA
Marathon Electric
MangaPlus 432PSL1268 (older generator)
Serial # LM-217323-TO95
John Deere 6081HF070
Serial # RG6081H296673
2 250 kW
313 kVA
Marathon Electric
MangaMax DVR 433RSL4019
Serial # WA-568180-0109
John Deere 6081HF070
Serial # RG6081H296672
3 117 kW
146 kVA
Marathon Electric
MangaPlus 431CSL6202
Serial # 705888-0209
John Deere 4045HF485
Serial # 4045HF485
Total generation capacity: 547 kW
The engines, control systems and two of the generators were installed in 2008 by Marsh Creek LLC. The
John Deere diesel engines have electronic isochronous governors, and the power house has automated
switchgear, with Woodward easYgen 3000 generator control panels and Satek PM 130EH power meters.
The Atmautluak School has its own diesel generator,which is connected to the local distribution system
of Atmautluak Joint Utilities. This generator is used as backup for the school if the community power
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generation system is down, or to relieve energy demand on the Atmautluak Joint Utilities power plant.
For example, the power plant operator reported that the school’s generator was turned on for several
days in August 2010 to reduce load on the overall community grid when the Atmautlua k Joint Utilities
power plant was experiencing high temperatures on its diesel engines during relatively warm weather.
Preferred Wind Turbine Site, “site 1”
Location (NAD83): 60° 51.728’ N, 162° 17.225’ W.
The community’s preferred wind turbine site, “site 1”, is located about 0.45 miles northwest of the
Atmautluak power plant, and about 800 feet NW of the location where the met tower was i nstalled
between 2005 and 2006.The site is located entirely on land owned by Atmautluak Limited, the local
village corporation.
A 25’-wide right-of-way easement exists through this site for a winter trail between Bethel and
Nunapitchuk that is no longer used, but is recorded in BLM records. A different trail is now used in
winter. Atmautluak Traditional Council is working with BLM on this issue, and is expected to resolve this
issue in the near future.
Alternate Wind Turbine Site, “site 2”
Location (NAD83): 60° 51.229’ N, 162° 17.102’ W.
The site is located entirely on land owned by Atmautluak Limited, the local village corporation.A
particularly marshy area exists between the existing boardwalk/power line/homes and this site. After
freezeup, this area is more heavily used area than the preferred wind turbine site.
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Figure 2: Aerial photo of Atmautluak showing proposed wind turbine sites, and approximate routes of
existing power distribution lines
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3.Initial Environmental Review
The environmental permitting steps below are based on the publication Alaska Wind Energy
Development: Best Practices Guide to Environmental Permitting and Consultations, a study done by the
URS Corporation for the Alaska Energy Authority in 2009.
Alaska Department of Environmental Conservation
Alaska Pollution Discharge Elimination System
State regulations (18 AAC 83 APDES) require that all discharges, including storm water runoff, to surface
waters be permitted under the Alaska Pollutant Discharge Elimination System (APDES) permit program,
which aims to reduce or eliminate stormwater runoff that might contain pollutants or sediments from a
project site during construction. The construction of one or more wind turbines, and the connecting
access road and power line, in Atmautluak would likely disturb one acre or more of soil, and thus must
be permitted under the State of Alaska’s Construction General Permit (CGP) and have a Storm Water
Pollution Prevention Plan (SWPPP).The construction contractor must submit a Notice of Intent (NOI) to
Alaska Department of Environmental Conservation (DEC) before submitting a SWPPP. The DEC issues
the final APDES permit for the project after review and public comment periods.
US Fish and Wildlife Service
Atmautluak is located in an area that is mapped by the Anchorage US Fish and Wildlife Service (USFWS)
Field Office as “No Consultation Necessary” for listed species under the Endangered Species Act (ESA).
This map is called “ESA Listed Species Consultation Guide –Anchorage Fish and Wildlife Field Office”.
The legend states “If your project is located within Solid Green on this map, there are no listed species
present within your project area and no consultation is necessary.”
Atmautluak Traditional Council must also be aware of USFWS regulations and guidance under the
Migratory Bird Treaty Act, which prohibits the taking of active bird nests, their eggs and young. USFWS
has developed “Bird Windows” statewide that prohibit clearing and construction activity. The bird
window in the Atmautluak area is May 5 to July 25 except for Canada geese and swan habitat where the
window begins April 20 and for black scoter habitat where the window closes August 10. Clearing
before or after these dates is allowed. Clearing and construction activity during the window is not
allowed.
The USFWS Wind Turbine Guidelines Advisory Committee developed guidelines and recommendations
for wind power projects to avoid impacts to birds and bats. These recommendations were sent to the
Secretary of the Interior in March 2010 and should be referred to during design and construction.
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Federal Aviation Administration
Determination of No Hazard to Air Navigation
Atmautluak Traditional Council will be required to file an FAA Form 7460-1 (Notice of Proposed
Construction or Alteration), as the proposed wind turbine site(s) are less than one mile from the
Atmautluak airport. Obstruction lighting on the wind turbine(s) is likely to be required.
Alaska Department of Natural Resources
Alaska Coastal Management Program consistency review
The Alaska Department of Natural Resources (ADNR)-administered Alaska Coastal Management
Program (ACMP) evaluates projects within the Coastal Zone, which includes Atmautluak, for consistency
with statewide standards and other local Coastal District enforceable policies. The ACMP consistency
review is a coordination process involving all federal and state permitting authorities within the
Ceñaliuriit Coastal Resource Service Area (CRSA), where Atmautluak is located.
The project design consultant will, on behalf of Atmautluak Traditional Council, fill out a Coastal Project
Questionnaire (CPQ) and consistency evaluation form and submit it to ADNR’s Division of Coastal and
Ocean Management (DCOM). After a public comment and review period, DCOM will issue a final
consistency determination.
State Historic Preservation Office (SHPO) consultation
The project design consultant will complete a consultation under Section 106 of the Historic
Preservation Act with the State Historic Preservation Office (SHPO), to receive a letter concurring that a
wind project would affect no historic properties.
US Army Corps of Engineers
The US Army Corps of Engineers (USACE) requires the placement of fill in “waters of the United States”,
including wetlands and streams, under Section 404 of the Clean Water Act (CWA). Because much or all
of the proposed wind turbine site(s) in Atmautluak are located on wetlands, Atmautluak Traditional
Council must receive a Section 404 permit from the Alaska District USACE.
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4.System Configuration Options
Wind-diesel power systems are categorized based on their average penetration levels, or the overall
proportion of wind-generated electricity to the total amount of electric energy supplied to the system.
Commonly used categories of wind-diesel penetration levels,are low penetration, medium penetration,
high penetration, and high penetration-diesels off, as summarized in Table 3. The average wind
penetration level is roughly equivalent to the overall amount of diesel fuel saved. In general, the higher
the level of wind penetration that the system is designed for, the more complex and expensive a control
system and demand-management strategy is required.
Table 3: Categories of wind-diesel penetration levels
Penetration
Category
Penetration Level Operating characteristics and system requirements
Instantaneous Average
Low Less than 50% Less than 20%Diesel generation runs full-time
Requires little or no changes to existing diesel control
system
All wind energy generated goes to the primary load
Medium 50% to 80% 20% to 50%Diesel generation runs full-time
Requires relatively simple new control system with
automation and set-point control, and secondary loads
such as electric boilers
At high wind power levels, secondary loads are
dispatched to absorb energy not used by the primary
load, or wind generation is curtailed
High 80% to 200% 50% to 100%Diesel generation may be shut down during periods of
high wind power levels
Requires sophisticated new control system and
additional components (including demand-managed
devices and more advanced controls to regulate grid
voltage and frequency)
At high wind power levels, secondary loads and/or
demand-managed devices are dispatched to absorb
energy not used by the primary load.
High-
Diesels Off
200% and
above
Greater than
50%
Diesel generation will be shut down during periods of
high wind power levels
Requires sophisticated new control system, additional
wind capacity, and additional components (including
demand-managed devices and more advanced controls
to regulate grid voltage and frequency)
At high wind power levels, secondary loads and/or
demand-managed devices are dispatched to absorb
energy not used by the primary load.
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Proposed system configuration of Atmautluak wind-diesel system alternatives
Low penetration wind-diesel systems require the fewest modifications to the existing system.However,
they tend to be less economical due to the limited annual fuel savings compared to the total wind
system installation costs.It is therefore recommended that Atmautluak’s wind energy be developed as a
medium-or high-penetration system.
Listed below are the main components of a medium-high penetration wind-diesel system:
Wind turbine(s)
Tower and foundation
Power line (including transformers and cabling)
Managed load devices
Power control electronics
Communicationsand monitoring systems
Components of the conceptual Atmautluak wind-diesel system:
Two Vestas V17 or two Northern Power Systems NW100 Arctic wind turbines (Alternative A-180
kW; Alternative B-200 kW)installed on permafrost foundations.
A new 7.2 kV above-ground power line, approximately 2700’ in length, from the preferred wind
turbine site (“site 1”) to the existing power plant/tank farm area. During the engineering design
study, the feasibility of connecting the new 7.2 kV above-ground line to the end of the existing
feeder line. This option would save costs because the new line would have a shorter distance of
about 1000’. New transformers will be installed at either end of the line. The poles would also
carry a communication line between the wind turbine site and the power plant area.
A new modular building/exterior module, possibly the size of a 40’ shipping container, to be
installed adjacent to the existing diesel power plant building. The power line from the wind
turbine site would connect directly to this new building/module, which would house the
synchronous condenser, electric boiler/boiler grid interface, power control equipment , battery
bank, and an insulated hot water tank. The hot water tank, as well as a pump connected to the
district heat system,could be also integrated into a new heat recovery system on the existing
diesel power plant.
Some new electronic control systems and panels in the existing power plant building will be
needed.
A district heating system, consisting of an insulated above-ground pipe about 900’ in length,
connecting the electric boiler/hot water tank near the powerhouse to the store, tribal office,
washeteria and school.
Three drawings are provided below showing the conceptual Atmautluak wind-diesel system design: an
electrical one-line diagram (Figure 3), site plan (Figure 4), and permit sketch (Figure 5).
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Figure 3: Conceptual Atmautluak wind-diesel system one-line diagram (drawing by Jason McGrew)
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Figure 4: Conceptual Atmautluak wind-diesel system site plan (drawing by Jason McGrew)
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Figure 5:Conceptual Atmautluak wind-diesel system permit sketch (drawing by Jason McGrew)
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Wind turbine generator options (see specification sheets in Appendix E)
Vestas V15/V17
Several companies worldwide are now refurbishing the Vestas V15 and V17 wind turbines for
resale. The V15 model and V17 model are very similar in construction but have power ratings of
65kW and 90kW respectively.The refurbished Vestas machines include a warranty.
Budgetary cost of a refurbished V15 is $150,000 and a V17 is $200,000.
Vestas V15 and V17 turbines are presently installed and operating in Alaska. Kotzebue,
Kokhanok and Nikolski have installed these machines. The machine can be tilted up thus not
requiring a crane for erection which can be a cost savings.
The Vestas V15 and V17 use an induction type generator and stall regulation.
Northern Power Systems Northwind100
The Northwind100 (or NW100) has a 100 kW nominal rated capacity
Output is 3 phase, 480 VAC, 60 Hz.
The NW100 unit requires a tubular tower at least 30 m (100’) in height (foundation required)
Manufactured by Northern Power Systems of Barre, Vermont
Cost of NW100 Arctic (not including installation or shipping): $375,000
The Alaska Village Electric Cooperative (AVEC) and Kotzebue Electric Association have extensive rural
Alaska experience working with the Northwind 100 (or NW100), which has proven more reliable than
other similar-sized turbines. The NW100 is the standard workhorse of AVEC’s wind-diesel installations,
including the three wind turbines that AVEC has installed at Kasigluk. The NW100 Arctic, a new version
of the turbine with additional features and design enhancements for cold-climate operation, is
recommended for the Atmautluak wind-diesel system.
Bergey Excel S
The Bergey Excel S has a 10 kW nominal installed capacity.
Output is single-phase, 240 VAC, 60 Hz.
Can be mounted on Bergey’s 30 m tilt-up tower (no foundation required)
Cost of Excel S listed on Bergey website: $31,770.
Manufactured by Bergey WindPower Co., Norman, Oklahoma
The advantage of an array of smaller, lightweight turbine units like the Bergey is that they require no
foundations, only anchors for guy wires. Guyed, tilt-up towers are much easier, cheaper and faster to
construct than a tubular tower with a concrete foundation, but present more avian hazards due to the
guy wires. However, to match the capacity of a single NW100 turbine, ten Excel S turbines would need
to be installed, taking up a much larger land footprint for an equivalent capacity. Cabling and
transformers, power control,and interconnection to the existing Atmautluak power system are likely to
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be more complex. Operations and maintenance costs may also be higher for an array of Excel S units,
compared to one or two larger turbines.An in depth analysis of this option was not performed.
Wind-diesel integration controls
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 Atmautluak power plant, or in a new module adjacent to it. The supervisory controller would
select the optimum system configuration based on village load (demand) and available wind power.
Two examples of a wind-diesel system supervisory controller are the Powercorp control system and the
Sustainable Automation control system. Both are pre-configured to operate with multiple diesel gen-
sets, wind systems, and demand-managed devices. The Powercorp system is broken into several layers
of operation, with each controller device in communication with the others:
Station Controller: schedules each of the lower units, performs remote control functions and
stores collected system data
Generation Controller: monitors and controls a single diesel generator
Demand Controller: monitors, controls, and schedules demand-managed devices such as a
synchronous condenser or electric boiler, to insure that sufficient generation capacity is online.
Feeder Monitor: monitors vital statistics of the distribution feeder, including ground fault
information
Wind Turbine Controller: monitors the wind turbine it is connected to, and dispatches wind
turbines depending on the wind-diesel’s system’s overall load, and the availability of wind
energy.
The Sustainable Automation control system uses many similar components to the Powercorp system.
Functions of the Sustainable Automation Hybrid Power System Supervisory Controller include:
Diesel dispatch: starting and stopping the diesel generator(s) according to the diesel capacity
required
Wind turbine dispatch:allow/inhibit wind turbine operation as necessary
Secondary load dispatch:determining the required amount of power sent to the secondary load
at any given instant
Diesel status monitoring
Wind turbine status monitoring
Performance data logging:kWh and run-time totals, alarms, etc.
Fault detection and annunciation
Provide for remote access via dialup or internet connection
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Several Alaskan electrical engineering and construction firms have also been involved with wind-diesel
power systems. Electric Power Systems, Inc. of Anchorage has been working with Kotzebue Electric
Association on their large wind diesel project and have also worked with Cordova electric on a hydro-
diesel project. They have extensive power generation and PLC control experience.
Synchronous condenser
A synchronous condenser, sometimes called a synchronous compensator, is a specialized synchronous
electric motor whose shaft is not attached to anything, but spins freely. Its excitation field is controlled
by a voltage regulator to either generate or absorb reactive power as needed to support the grid’s
voltage or to maintain the grid’s power factor at a specified level. Such power factor and voltage support
is essential for a wind-diesel system’s reliability.
For a power system the size of Atmautluak’s, a synchronous condenser was considered to be a more
economic option for voltage and reactive power support than a flywheel as discussed below.
Secondary/interruptible loads
Secondary load or rapidly shifting on or off discretionary (or “dump”) loads during periods of high winds
is required for a wind-diesel hybrid power system to operate reliably and economically. The secondary
load converts excess wind power into thermal power (heat) for use in space and fluid heating.
Electric heating, either in the form of electric space heaters or electric water boilers, should be explored
as a means of displacing oil heating fuel with wind-generated electricity. It must be emphasized that
electric heating isonly economically viable when using excess electricity provided by a renewable (no -
fuel) energy source such as wind, and not from diesel-generated power. It is typically assumed that one
gallon of heating fuel oil is equivalent to 41 kWh of electric heat
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
Atmautluak power plant building, would need to be able to absorb up to 200 kW of instantaneous
energy (full output of the wind turbines). The grid interface monitors and maintains the temperat ure 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.
The school, tribal building and washeteria represent the largest heating loads in Atmautluak.There is no
form of heat recovery presently employed at the diesel powerhouse, nor is there any kind of local
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district heating system.Potential discretionary electric heating loads for a future wind-diesel system
identified during the site visit, include:
Electric boiler system at the school
An electric boiler/recovered heat module could be installed next to the existing diesel
powerhouse, with a hot water pipe (hydronic heating loop) extending a length of approximately
900’ to the store, tribal office,washeteria and school (Figure 6). The central location of all of
these buildings, in relation to the existing power plant, could make a district heating system
economically feasible.
Existing electric heat trace system used for sewer and water line s
Figure 6: Conceptual layout of hydronic heating loop (hot water pipe) for district heating system in
central Atmautluak
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.
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Flywheels
A flywheel energy system has the capability of short-term energy storage to further smooth out short-
term variability of wind power, and has the additional advantage of frequency regulation. However, a
flywheel system is much more expensive than a synchronous condenser. A Powercorp flywheel unit of
500 kW capacity, the smallest commercially available for a remote wind-diesel application such as
Atmautluak’s, has an estimated installed cost of about $2 million, according to a 2009 review of energy
storage technologies for the Alaska Energy Authority by WHPacific. This is the equivalent estimated
installation cost of an entire 200-kW Atmautluak wind-diesel system using a synchronous condenser.
Batteries
Battery storage is a well-proven technology and has been used in Alaskan power systems including
Fairbanks (Golden Valley Electric Association), Wales and Kokhanok. Kotzebue Electric Association will
be installing a 250kW battery storage system in 2011. 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 between 5 and 15 minutes long.
Storage for several hours or days is also possible with batteries, but requires more capacity (and more
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 tend to be heavy to ship, and many contain toxic materials that
require removal at the end of a battery’s useful life.
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 1.2VDC.Recent
advances in power electronics have made solid state inverter/converter systemscost effective and
preferable a power conversion device. The Kokhanok wind-diesel system used a 300VDC battery bank
coupled to a “grid-forming” power converter for production of utility-grade real and reactive power.
The solid state converter system in Kokhanok will be commissioned in the spring of 2011 and will be
monitored for reliability and effectiveness.
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, by the July 2009 report on energy storage by the Uni versity of Alaska’s
Alaska Center for Energy and Power. Nickel-cadmium (NiCad) batteries have also been used in rural
Alaska applications, such as the Wales wind-diesel systems.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.A November 2010 quote from Sustainable
Automation reported the equipment-only cost of a 250 kW/480 kWh capacity lead-acid battery system
would cost $315,000, not including shipping or other installation costs.
Atmautluak Wind-Diesel Study Atmautluak Traditional Council
WHPacific, Inc.24 November 17, 2010
Operations and Maintenance
According to AVEC, annual O&M costs are $3,500 per turbine per year (for existing NW100 units),
consisting mainly of one maintenance visit per year. For the purposes of the HOMER economic
modeling in this report (see section 5), an annual maintenance cost of $5,000 per turbine is assumed.
Because of the relatively large number of NW100 turbines already deployed in the Yukon-Kuskokwim
Delta region, technical personnel are already based in the region and can assist with maintenance and
repairs. Northern Power also offers training at itsmanufacturing facility in Vermont for local operators.
Rough Order of Magnitude (ROM) Cost Estimates for Atmautluak Wind-Diesel
Alternatives
The ROM cost estimates for Alternative A (two Vestas V17s) and Alternative B (two NW100s) are based
on a review of cost estimates for similar-scaled wind-diesel projects in the Yukon-Kuskokwim delta
region, both existing and proposed. A comprehensive design needs to be completed for more accurate
cost estimates.
Another possible alternative is the installation of one or more additional 100kW NW100 turbines at
AVEC’s existing wind turbine in Kasigluk, with a new power line connecting the Kasigluk-Nunapitchuk
system to Atmautluak. The Kasigluk wind farm was installed in 2006 with three NW100 turbines, for a
total of 300 kW of wind capacity, with a 3-mile power line connecting Kasigluk to Nunapitchuk.A new
power line would need to be built a distance of approximately 7 miles, to connect Nunapitchuk to
Atmautluak. Based on AVEC’s recent inter-village power line construction costs of $350,000/mile, this
line would cost about $2,450,000. It could be more expensive than this, because of the numerous lakes
and ponds between Atmautluak and Nunapitchuk.This is higher than the preliminary cost estimates of
alternatives A and B below for an Atmautluak-only wind-diesel system. Therefore, an intertie power line
from AVEC’s existing Kasigluk-Nunapitchuk system to Atmautluak is not recommended.
Alternative A:Two Vestas V17 turbines in Atmautluak
The Vestas V17 turbines would be mounted on a standard 30 m (100’)tubular towers, installed atop a
concrete foundation designed for marshy, permafrost-laden soil.
Preliminary rough order of magnitude (ROM) cost estimate for Alternative A: $1,3 00,000
Table 4: ROM Cost Estimate for Design and Permitting Phase -Alternative A
Project scoping and contractor solicitation completed 10,000
Permit applications completed 10,000
Environmental assessment/mitigation plans 20,000
Permitting, rights-or-way, resolution of land use, site control 50,000
Final system design 90,000
Final cost estimate 10,000
Updated economic and financial analysis 10,000
Final business and operational plan 10,000
Design and Permitting Phase Total $210,000
Atmautluak Wind-Diesel Study Atmautluak Traditional Council
WHPacific, Inc.25 November 17, 2010
Table 5: ROM Cost Estimate for Construction and Commissioning Phase-Alternative A
Project management 75,000
Wind turbine/integration equipment procurement 650,000
Foundation material procurement 50,000
Mobilization/demobilization costs 160,000
Site access and foundation installation 50,000
Turbine/tower erection 150,000
Power line extension 100,000
Construction survey/as-built drawings 10,000
System integration/controls/electric boiler/diesel generation system upgrade 250,000
Training 20,000
Construction and Commissioning Phase Total $1,515,000
Alternative B: Two 100 kW NW100 turbines in Atmautluak-
Preliminary rough order of magnitude (ROM)cost estimate for Alternative B: $2,000,000
Table 6: ROM Cost Estimate for Design and Permitting Phase -Alternative B
Project scoping and contractor solicitation completed 10,000
Permit applications completed 10,000
Environmental assessment/mitigation plans 20,000
Permitting, rights-or-way, resolution of land use, site control 50,000
Final system design 90,000
Final cost estimate 10,000
Updated economic and financial analysis 10,000
Final business and operational plan 10,000
Design and Permitting Phase Total $210,000
Table 7: ROM Cost Estimate for Construction and Commissioning Phase-Alternative B
Project management 75,000
Wind turbine/integration equipment procurement 1,125,000
Foundation material procurement 50,000
Mobilization/demobilization costs 200,000
Site access and foundation installation 70,000
Turbine/tower erection 200,000
Power line extension 100,000
Construction survey/as-built drawings 15,000
System integration/controls/electric boiler/diesel generation system upgrade 250,000
Training 20,000
Construction and Commissioning Phase Total $1,790,000
Atmautluak Wind-Diesel Study Atmautluak Traditional Council
WHPacific, Inc.26 November 17, 2010
5.Economic Analysis
HOMER software was used to simulate conditions at Atmautluak with two Vestas V17 or two Northwind
100 wind turbines (based on wind resource information collected by the AEA met tower), running in
conjunction with the existing diesel power plant.This software can provide a comparison of estimated
fuel savings (Table 8),levelized cost of electricity (Table 9) and emissions (Table 10)from diesel-only and
conceptual wind-diesel configurations.HOMER calculates gross energy production with no allowance for
power plant downtime, turbine or generator maintenance , equipment curtailment or other reasons.
Included in Appendix D are HOMER Systems Reports for modeling the following six scenarios:
Three, two, one and zero (base case)Vestas V17 turbines at $4.58/gallon ($1.45/liter) fuel cost
Two, one and zero (base case) NW100 turbines at $4.58/gallon ($1.45/liter) fuel cost
Main assumptions used in the HOMER model for the conceptual Atmautluak
wind-diesel system
$1,725,000 total installed cost for 2-Vestas V17 turbine (180 kW) wind system
$2,325,000 total installed cost for 2-Northern Power Systems NW100 Arctic turbine (200 kW)
wind system
Annual O&M costs are $9,250 for each Vestas wind turbine and $10,250 for each Northern
Power Systems wind turbine.
2% interest rate
20 year project life
Assumed fuel cost is fixed for the 25-year project, and does not increase.
The annual electric energy consumption of approximately 679,000 kWh (based on Atmautluak’s
2009 generation statistics) is fixed, and does not increase.
The generation-only cost of diesel-generated electricity at the Atmautluak power plant is
$0.51/kWh at $4.58/gallon fuel cost, given a generation efficiency of 12.6 kWh/gallon (based on
Atmautluak Joint Utilities 2009 statistics).
The non-generation cost of electricity in Atmautluak is assumed to be $0.24/kWh, which
combined with the assumed diesel generation cost of $0.51, is equivalent to the present retail
rate of electricity of approximately $0.70/kWh (the diesel-only base case).
Only the two newest existing diesel gensets in the Atmautluak power plant will be used:
o Generator 2 (250 kW)
o Generator 3 (117 kW)
Estimated Annual Renewable Fraction and Capacity Factor
Renewable fraction (penetration level):37% for Alternative A,48% for Alternative B.
Capacity factor on net wind production:29.9% for Alternative A,36.2%for Alterntative B.
Atmautluak Wind-Diesel Study Atmautluak Traditional Council
WHPacific, Inc.27 November 17, 2010
Estimated Annual Wind Energy Production
HOMER software estimated gross annual wind production to be:
472 MWh with 214 MWh excess electrical energy for Alternative A
635 MWh with 327 MWh excess electrical energy for Alternative B
Estimated Fuel Savings
Table 8: Results of HOMER modeling for Atmautluak wind-diesel system alternatives, fuel savings
Alternative Annual fuel
consumption
(gallons)
Annual fuel
savings Annual fuel cost savings
(gallons)%$4/gal. diesel $5/gal. diesel $6/gal. diesel $7/gal.diesel
Base case
(diesel only)57,529 0 0%0 0 0 0
Alternative A
33,291 24,238 42%$96,952 $121,190 $145,428 $169,666
Alternative B
27,015 30,514 53%$122,056 $152,570 $183,084 $213,598
Cost of Energy
As shown in Table 9, Alternative B has the lowest levelized cost of energy predicted by HOMER at $4/gal.
diesel and $5/gal. diesel. Alternative A is competitive with diesel at prices higher than $5/gal.
Table 9: Results of HOMER modeling for Atmautluak wind-diesel system alternatives, cost of energy
Alternative Levelized cost-of-energy
($/kWh)
$4.58/gal.
diesel
Base case (diesel only)0..506
Alternative A 0.490
Alternative B 0.496
Atmautluak Wind-Diesel Study Atmautluak Traditional Council
WHPacific, Inc.28 November 17, 2010
6.Development Plan
The preliminary economic feasibility analysis by the HOMER software, based on the preliminary cost
estimates presented in this report, indicates that Atmautluak very likely would save on energy costs by
installing a wind power generation facility. More detailed design, permitting/environmental studies and
economic analysis is warranted to confirm the economic feasibility before funding can be secured, o r
before a decision is made to proceed with construction. The proposed project schedule below is a
development plan which assumes that the Alaska Energy Authority approves funding, as part of the
Renewable Energy Fund-Round IV grant program, for final design and permitting phases of the
Atmautluak wind-diesel project, as well as construction funding the subsequent year. S uch an (ideal)
funding scenario would result in an operational wind system in March 2013. This schedule also assumes
that permitting and regulatory approvals are simple due to the lack of significant environmental
impacts, and are secured by mid-2012.Other grant programs and funding sources besides Alaska Energy
Authority are possible such as energy project grant/loan programs of the US Dept. of Energy and the US
Dept. or Agriculture-Rural Development.
Design and Permitting
Round 4 AEA award announcements May 2011
Negotiation /final grant agreement July 2011
Authorization to proceed September 2011
Initiate permitting June 2011
Resolution of right-of-way issues summer 2011
Electrical system design -Complete May 2012
Civil engineering design May 2012
Engineer’s cost estimate August 2012
Final business and operational plan completed August 2012
RFP/bid documents October 2012
Construction -projected
Order wind turbines & towers March 2012
Turbines shipped September 2012
Final civil design and site plan August 2012
Turbines --delivered and on site October 2012
Complete turbine install and equipment integration February 2013
Final integration and testing March 2013
Complete turbine commissioning April 2013
Secondary load controller commissioning October 2013
1
Atmautluak Wind-Diesel Feasibility Study
Appendix A:Atmautluak AEA Wind Energy Resource Report
www.akenergyauthority.org/programwind.html Page 1 of 9 December 2006
813 W. Northern Lights Blvd.
Anchorage, AK 99503
Phone: 907-269-3000
Fax: 907-269-3044
www.akenergyauthority.org
Wind Resource Assessment for
ATMAUTLUAK, ALASKA
Date last modified: 1/5/2007
Compiled by: Cliff Dolchok & James Jensen
SITE SUMMARY
Site #: 1045
Latitude (NAD27): 60
Longitude (NAD27): 162 16 53.6
Magnetic Declination: 14 31
Tower Type: 30-meter NRG Tall Tower
Sensor Heights: 30m, 20m
Elevation: 4.3 meters (14 ft)
Monitor Start: 10/21/2005 00:00
Monitor End: 12/4/06 10:50
Atmautluak lies on the west bank of the Pitmiktakik River in the Yukon-Kuskokwim
delta, 20 miles northwest of Bethel. Atmautluak is located in the Bethel Recording
District. (source: BearingSea.com)
WIND RESOURCE SUMMARY
Annual Average Wind Speed (30m height): 7.16 m/s (16.0 mph)
Average Wind Power Density (30m height): 451 W/m
2
Wind Power Class (range = 1 to 7): 5
Rating (Poor, Marginal, Fair, Good, Excellent, Outstanding, Superb):Excellent
Prevailing Wind Direction: North
In October 2005, a 30-meter meteorological tower was installed in Atmautluak.
The purpose of this monitoring effort was to evaluate the feasibility of utilizing
utility-scale wind energy in the community. The meteorological data collected
allows us to estimate the potential energy production from various types of wind
turbines.
Alaska Energy Authority ATMAUTLUAK, AK Wind Resource Assessment
www.akenergyauthority.org/programwind.html Page 2 of 9 December 2006
INTRODUCTION
On initial review, the community of Atmautluak appears to be a strong candidate for wind power. The wind
resource map below shows that Atmautluak is in close proximity to areas with wind resource ratings ranging from
Class 4 to Class 6. Areas of Class 4 and higher are considered suitable for utility-scale wind power development.
Source: AWS Truewind
Figure 1. Wind Resource Map of Alaska
With support from the Alaska Energy Authority, a 30-meter tall meteorological tower was installed in the village of
Atmautluak. The purpose of this monitoring effort was to verify the wind resource in Atmautluak and evaluate the
feasibility of utilizing utility-scale wind energy in the community. This report summarizes the wind resource data
collected and the long-term energy production potential of the site.
Alaska Energy Authority ATMAUTLUAK, AK Wind Resource Assessment
www.akenergyauthority.org/programwind.html Page 3 of 9 December 2006
SITE DESCRIPTION
The photos below document the meteorological tower equipment that was installed in Atmautluak.
Figure 2. Photos of the Met Tower Installation in Atmautluak, AK
The photos in Figure 3 illustrate the surrounding ground cover and any major obstructions, which could affect how
the wind flows over the terrain from a particular direction. As shown, the landscape surrounding the met tower site
is free of obstructions and relatively flat.
SW W NW N
NE E SE S
Figure 3. Views Taken from Met Tower Base
Table 1 lists the types of sensors that were used, the channel of the data logger that each sensor was wired into,
and where each sensor was mounted on the tower.
Table 1. Summary of Sensors Installed on the Met Tower
Ch # Sensor Type Height Offset Boom Orientation Arial view of equipment on tower
N
NE
E
SE
S
SW
W
NW
CH1, 30m anem
CH2, 30m anem
CH3, 20m anem
Tower
CH7, 30m anem
1 #40 Anemometer 30 m NRG Standard
2 #40 Anemometer 30 m NRG Standard
3 #40 Anemometer 20 m NRG Standard
7 #200P Wind Vane 30 m
9 #110S Temperature 2 m NRG Standard -
Alaska Energy Authority ATMAUTLUAK, AK Wind Resource Assessment
www.akenergyauthority.org/programwind.html Page 4 of 9 December 2006
WIND DATA RESULTS FOR ATMAUTLUAK MET TOWER SITE
Table 2 summarizes the amount of data that was successfully retrieved from the data logger at the met tower site.
There was a large amount of data loss during March due to icing of the sensors. A software program called
Windographer (www.mistaya.ca) was used to fill the gaps. Windographer uses statistical methods based on
patterns in the data surrounding the gap, and is good for filling short gaps in data. As such, the data from March is
the most questionable since Windographer had to fill large gaps in data.
Table 2. Data Recovery Rate for Met Tower Anemometers
Month Data Recovery Rate Data Loss Due to Icing
Oct. 2005 98.8%19
Nov. 2005 85.5%536
Dec. 2005 98.5%66
Jan. 2006 94.7%222
Feb. 2006 99.9%4
Mar. 2006 27.5%890
Apr. 2006 87.0%488
May 2006 97.8%95
Jun. 2006 100%0
Jul. 2006 100%0
Aug. 2006 100%0
Sep. 2006 100%0
Oct. 2006 97.7%102
Nov. 2006 92.4%302
Dec. 2006 99.6%2
Wind Speed Measurements
The table below summarizes the wind speed data collected at the Atmautluak met tower site.
Table 3. Summary of Atmautluak Wind Speed Data, 30-meter Height
Annual Average 7.16 m/s
Highest Month February
Lowest Month September
Hour of Peak Wind 23
Max 10-minute average 23.1 m/s
Max gust 30.2 m/s
Alaska Energy Authority ATMAUTLUAK, AK Wind Resource Assessment
www.akenergyauthority.org/programwind.html Page 5 of 9 December 2006
The seasonal wind speed profile shows that the winter months are generally windier than the summer months. The
daily wind speed profile shows that wind speeds are typically greater in the afternoon and evening hours and
calmer in the morning. The data that makes up these graphs is listed in Table 4.
Table 4. Estimated Long-Term Wind Speeds at Met Tower Site, 30m Height (m/s)
Hour Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Avg
0 7.1 9.9 9.2 8.5 6.7 6.2 5.9 6.0 5.1 6.8 7.7 8.1 7.3
1 7.2 9.7 8.4 8.5 6.5 6.3 5.9 6.0 5.0 6.9 7.6 8.2 7.2
2 6.9 10.0 7.9 8.4 6.7 6.2 5.9 5.7 5.0 6.8 7.8 8.2 7.1
3 7.0 10.1 7.3 8.7 7.0 6.3 5.7 5.6 5.0 6.6 7.5 8.4 7.1
4 7.1 9.9 8.3 8.5 6.3 6.3 5.9 5.5 5.0 6.5 7.6 8.3 7.1
5 7.1 9.7 9.8 8.4 6.1 6.1 5.9 5.4 5.1 6.6 7.7 8.3 7.2
6 7.1 9.7 9.6 8.2 6.0 6.1 5.8 5.2 5.2 6.7 7.4 8.3 7.1
7 7.0 9.7 10.2 7.9 5.7 6.2 5.6 5.0 4.7 6.5 7.5 8.3 7.0
8 7.2 9.2 10.0 7.9 5.8 6.2 5.6 5.2 4.7 6.5 7.5 8.4 7.0
9 7.1 9.3 9.1 7.9 5.7 6.4 5.6 5.2 4.6 6.3 7.4 8.4 6.9
10 7.0 8.9 8.8 7.8 5.7 6.4 5.7 5.3 4.9 6.4 7.5 8.2 6.9
11 7.2 9.0 9.2 8.0 6.0 6.3 5.7 5.6 4.9 6.4 7.6 8.3 7.0
12 7.2 9.2 10.5 8.1 6.1 6.3 5.9 5.7 4.8 6.6 7.6 8.3 7.2
13 7.3 9.1 9.7 8.4 6.1 6.2 5.9 5.6 5.1 6.7 7.6 8.3 7.2
14 7.2 9.2 9.3 8.7 6.4 6.2 5.7 5.5 5.2 7.0 7.5 8.2 7.2
15 7.4 9.5 9.7 8.2 6.5 6.2 5.7 5.6 5.1 6.9 7.4 8.6 7.2
16 7.3 9.6 9.5 7.6 6.5 6.4 5.9 5.6 5.1 6.6 7.4 8.6 7.2
17 6.8 9.7 9.3 7.5 6.5 6.3 5.9 5.8 5.4 6.3 7.3 8.4 7.1
18 6.8 9.9 10.3 7.6 6.6 6.3 5.9 5.7 5.3 6.2 7.5 8.2 7.2
19 7.0 10.5 10.8 7.6 6.5 6.5 5.7 5.5 5.0 6.4 7.5 8.4 7.3
20 7.0 10.5 10.8 7.6 7.0 6.3 5.7 5.8 5.0 6.6 7.5 8.1 7.3
21 7.1 10.8 10.4 8.0 7.1 6.1 5.7 5.9 5.0 6.6 7.2 8.2 7.3
22 7.1 10.6 9.9 8.1 7.0 5.6 5.6 6.1 5.0 6.7 7.4 8.3 7.3
23 6.9 10.3 10.2 8.6 7.1 5.8 5.7 6.1 5.2 6.6 7.6 8.2 7.4
Avg 7.1 9.8 9.5 8.1 6.4 6.2 5.8 5.6 5.0 6.6 7.5 8.3 7.2
The estimated long-term average wind speed is 7.2 m/s (16.0 mph) at a height of 30 meters above ground level.
Wind Frequency Distribution
A common method of displaying a year of wind data is a wind frequency distribution, which shows the percent of
time that each wind speed occurs. Figure 4 shows the measured wind frequency distribution as well as the best
matched Weibull distribution, which is commonly used to approximate the wind speed frequency distribution.
Bin m/s Hrs/yr
1 72
2 290
3 518
4 728
5 962
6 1020
7 1019
8 952
9 826
10 676
11 487
12 359
13 278
14 190
15 122
16 83
17 60
18 41
Bin m/s Hrs/yr
19 24
20 16
21 10
22 8
23 4
24 4
25 4
26 2
27 1
28 2
29 1
30 1
31 1
32 0
33 0
34 0
35 0
Total: 8760
Figure 4. Wind Speed Frequency Distribution of Met Tower Data, 30-meter height
Alaska Energy Authority ATMAUTLUAK, AK Wind Resource Assessment
www.akenergyauthority.org/programwind.html Page 6 of 9 December 2006
The cut-in wind speed of many wind turbines is 4 m/s and the cut-out wind speed is usually 25 m/s. The frequency
distribution shows that about 90% of the time the wind in Atmautluak is within this operational zone.
Wind Direction
Wind power roses show the percent of total power that is available in the wind by direction. The annual wind power
rose for the Atmautluak met tower site is shown below.
Figure 5. Annual Wind Power Rose for Met Tower Site
Monthly wind power roses for the Atmautluak met tower site are shown below. The predominant wind direction
during the winter months is north, while the summer winds tend to come from the northwest. The wind rose for
March is not accurate due to the large amount of gap filled data.
Figure 6. Monthly Wind Power Roses for Met Tower Site
Alaska Energy Authority ATMAUTLUAK, AK Wind Resource Assessment
www.akenergyauthority.org/programwind.html Page 7 of 9 December 2006
Turbulence Intensity
Turbulence intensity is the most basic measure of the turbulence of the wind. Typically, a turbulence intensity of
around 0.10 is desired for minimal wear on wind turbine components. As shown in Figure 7, the turbulence
intensity from all directions is low and unlikely to contribute to excessive wear of wind turbines.
Dir Turbulence
Intensity
N 0.08
NE 0.10
E 0.09
SE 0.10
S 0.09
SW 0.08
W 0.09
NW 0.07
Ave 0.09
Figure 7. Turbulence Intensity Characteristics of Met Tower Site
Figure 7 plots the average turbulence intensity versus wind speed for the met tower site as well as for Category A
and B turbulence sites as defined by the International Electrotechnical Commission Standard 61400-1, 2
nd Edition.
Category A represents a higher turbulence model than Category B. In this case, the met tower data is significantly
less turbulent than both categories across the whole range of wind speeds.
Wind Shear
Typically, wind speeds increase with height above ground level. This vertical variation in wind speed is called wind
shear and is influenced by surface roughness, surrounding terrain, and atmospheric stability. The met tower is
equipped with anemometers at 20 and 30-meter heights so the wind shear exponent can be calculated and used to
adjust the wind resource data to heights other than those that were measured. Results are summarized below.
Month Wind Shear
Jan 0.12
Feb 0.26
Mar 0.21
Apr 0.18
May 0.27
Jun 0.11
Jul 0.29
Aug 0.22
Sep 0.29
Oct 0.23
Nov 0.18
Dec 0.14
Ave 0.21
Figure 8. Wind Shear Characteristics of Met Tower Site
As shown, the wind shear varies by month, direction of the wind, and time of day. The average wind shear for the
site is 0.21. Typical values range from 0.05 to 0.25.
have a significant effect on wind power production.
Alaska Energy Authority ATMAUTLUAK, AK Wind Resource Assessment
www.akenergyauthority.org/programwind.html Page 8 of 9 December 2006
LONG-TERM REFERENCE STATION
The year of data collected at the met tower site can be adjusted to account for inter-annual fluctuations in the wind
resource based on long-term measurements at a nearby weather station. The weather station closest to
Atmautluak is the Bethel Airport ASOS, located about 20 miles to the southeast. The hourly measurements from
the met tower were not closely correlated with those from the Bethel airport weather station (correlation coefficient
of less than 0.60). Due to the poor correlation between the two sites no adjustments could be made. The fact that
just for inter-annual fluctuations in wind speed decreases the confidence in our wind speed
estimates. Longer period of monitoring would increase that confidence.
POTENTIAL POWER PRODUCTION FROM WIND TURBINES
Various wind turbines, listed in Table 5, were used to calculate the potential energy production at the met tower site
based on the data collected. Although different wind turbines are offered with different tower heights, to be
consistent it is assumed that any wind turbine rated at 100 kW or less would be mounted on a 30-meter tall tower,
while anything larger would be mounted on a 50-meter tower. The wind resource was adjusted to these heights
based on the measured wind shear at the site. Also, since wind turbine power curves are based on a standard air
density of 1.225 kg/m3, the wind speeds measured at the met tower site are adjusted to create standard wind
speed values that can be compared to the standard power curves
Results are shown in Table 5. Among the results is the gross capacity factor, which is defined as the actual
amount of energy produced divided by the maximum amount of energy that could be produced if the wind turbine
were to operate at rated power for the entire year. Inefficiencies such as transformer/line losses, turbine downtime,
soiling of the blades, yaw losses, array losses, and extreme weather conditions can further reduce turbine output.
The gross capacity factor is multiplied by 0.90 to account for these factors, resulting in the net capacity factor listed.
CONCLUSION
This report provides a summary of wind resource data collected from October 2005 through December 2006 in
Atmautluak, Alaska. Both the raw data and the processed data are available on the Alaska Energy Authority
website.
It is a rough estimate that the long-term annual average wind speed at the site is 7.2 m/s at a height of 30 meters
above ground level. Taking the local air density and wind speed distribution into account, the average wind power
density for the site is 451 W/m
2. This information means that Atmautluak has an estimated Class 5 wind resource,
excellent The met tower wind data set was used to make predictions as to
the potential energy production from wind turbines at the site. The net capacity factor for large scale wind turbines
would range from 24 38%.
Alaska Energy Authority ATMAUTLUAK, AK Wind Resource Assessmentwww.akenergyauthority.org/programwind.html Page 9 of 9 December 2006Table 5. Power Production Analysis of Various Wind Turbine ModelsWind Turbine OptionsManufacturerInformationBergey10 kWFuhrlander FL3030 kWEntegrity 15/5065 kWFuhrlander FL100100 kWNorthern Power NW100100 kWFuhrlander FL250250 kWVestas V27*225 kWVestas V47*660 kWTower Height 30 meters 30 meters 30 meters 50 meters 50 meters 50 meters 50 meters 50 metersSwept Area 38.5 m2133 m2177 m2348 m2284 m2684 m2573 m21,735 m2Weight (nacelle & rotor)N/A 410 kg 2,420 kg 2,380 kg 7,086 kg 4,050 kg N/A N/AGross Energy Production (kWh/year)Jan2,374 11,188 18,740 36,259 29,575 82,121 74,145 248,272Feb2,374 11,432 20,290 38,523 31,354 86,292 77,962 256,118Mar2,506 11,959 20,609 39,481 32,170 87,654 79,595 263,588Apr1,657 7,677 11,686 23,300 19,040 50,789 46,499 162,511May1,807 8,349 12,932 25,632 20,950 56,579 51,642 179,533Jun1,436 6,686 9,837 19,789 16,153 43,187 39,464 139,897July1,250 5,907 8,477 17,139 13,954 40,128 36,619 130,924Aug1,791 8,311 12,795 25,407 20,753 62,436 56,969 196,264Sep1,910 8,860 14,030 27,645 22,598 67,342 61,685 209,774Oct2,071 9,626 15,415 30,273 24,726 70,964 64,580 219,479Nov1,892 8,712 13,709 27,106 22,153 63,305 57,723 197,903Dec2,165 10,121 16,466 32,146 26,267 73,911 67,079 227,042Annual23,233 108,828 174,985 342,696 279,693 784,705 713,961 2,431,302Annual Average Capacity FactorGross CF27% 41% 30% 39% 32% 36% 36% 42%Net CF 24% 37% 27% 35% 29% 32% 33% 38%
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Atmautluak Wind-Diesel Feasibility Study
Appendix B:Atmautluak Site & Powerhouse Field Visit Report
Brian Yanity visited Atmautluak on September 2, 2010 to assessthe diesel power generation system,
switchgear and ancillary equipment, as well as inspect possible wind turbine sites.Atmautluak Joint
Utilities staff provided tours of the existing diesel powerhouse, the prospective wind turbine sites,as
well as documentation and drawings.Daniel Waska, Atmautluak Tribal Administrator, presented a map
with potential wind turbine sites identified by the community: a preferred site and an “alternate” site
(see photos below).
The wind-diesel project concept, and pending grant proposal to the Alaska Energy Authority’s
Renewable Energy Fund,was presented at a community meeting hosted by the Atmautluak Traditional
Council.At the community meeting,several residents expressed report for wind energy, saying that a
reduction in the community’s overall diesel fuel consumption is highly desired.No concerns were
expressed other than a question about how the state grant funds would be administered.
Atmautluak Joint Utilities-Existing Power System
The cost of fuel purchased by Atmautluak Joint Utilities in 2010 was reported as $3.3688/gallon
(although some fuel purchased for $5.20/gallon was shipped in during the winter of 2010 due to a
temporary fuel shortage).The reported pre-subsidy retail cost of electricity for 2010 is $0.69860/kWh.
The reported retail rate for other fuels in Atmautluak was $5.45/gallon for heating fuel, $5.50/gallon for
gasoline.
The three diesel generator sets in the existing powerhouse (see photos below):
Genset
#
Capacity Generator Engine
1 180 kW
225 kVA
Marathon Electric
MangaPlus 432PSL1268 (older generator)
Serial # LM-217323-TO95
John Deere 6081HF070
Serial # RG6081H296673
2 250 kW
313 kVA
Marathon Electric
MangaMax DVR 433RSL4019
Serial # WA-568180-0109
John Deere 6081HF070
Serial # RG6081H296672
3 117 kW
146 kVA
Marathon Electric
MangaPlus 431CSL6202
Serial # 705888-0209
John Deere 4045HF485
Serial # 4045HF485
Total generation capacity: 576 kW
The engines, control systems and two of the generators were installed in 2008 by Marsh Creek LLC. The
John Deere diesel engines have electronic isochronous governors, and the the power house has
automated switchgear, with Woodward easYgen 3000 generator control panels and Satek PM130EH
power meters.
2
The Atmautluak School has its own diesel generator (see photos below), which isconnected to the local
distribution system of Atmautluak Joint Utilities. This generator is used as backup for the school if the
community power generation system is down, or to relieve energy demand on the Atmautluak Joint
Utilities power plant. For example, the power plant operator reported that the school’s generator was
turned on for several days in August 2010 to reduce load on the overall community grid when the
Atmautluak Joint Utilities power plant was experience high temperatures on its diesel engines during
relatively warm weather.
Heat Recovery and District Heat System Potential
There is no form of heat recovery presently employed at the diesel powerhouse, nor is there a ny kind of
local district heating system.
Potential discretionary electric identified heating loads for a future wind-diesel system:
Electric boiler system at the school
An electric boiler/recovered heat module could be installed next to the existing diesel
powerhouse, with a hot water pipe (hydronic heating loop) extending a length of approximately
900’ to the store, tribal office, washeteria and school.The central location of all of these
buildings, in relation to the existing power plant, could make a district heating system
economically feasible.
Existing electric heat trace system used for sewer and water lines.
Met Tower Site
Location:60° 51.686’ N, 162° 17.032’ W (NAD83 coordinates converted from NAD27 coordinates of the
site reported in the 2007 Alaska Energy Authority wind resource report, see Appendix A)
This is the location of the Alaska Energy Authority met tower installed in Atmautluak between October
2005 and December 2006.
Preferred Wind Turbine Site, “site 1”
Location (NAD83):60° 51.728’ N, 162° 17.225’ W
The community’s preferred wind turbine site, “site 1”, is located about 0.45 miles northwest of the
Atmautluak power plant, and about 800 feet NW of the location where the met tower was installed
between 2005 and 2006 (see coordinates above).The site is located entirely on land owned by
Atmautluak Limited, the local village corporation.
A 25’ wide right-of-way easement exists through this site for a winter trail between Bethel and
Nunapitchuk that is no longer used, but is recorded in BLM records. Today, a different trail is now used
in winter. Atmautluak Traditional Council is working with BLM on this issue, and is expected to resolve
this issue in the near future.
3
Preferred wind turbine site, facing north
Preferred wind turbine site, facing east
4
Preferred wind turbine site, facing southeast
Preferred wind turbine site, facing south
5
Preferred wind turbine site, facing southwest
Preferred wind turbine site, facing west
6
Alternate Wind Turbine Site, “site 2”
Location (NAD83): 60° 51.229’ N, 162° 17.102’ W
The site is located entirely on land owned by Atmautluak Limited, the local village corporation.
A particularly marshy area exists between the existing boardwalk/power line/homes and this site.After
freezeup,this area is more heavily used area than the preferred wind turbine site.
Alternate wind turbine site, facing north
7
Alternate wind turbine site, facing northeast
Alternate wind turbine site, facing east
8
Alternate wind turbine site, facing south
Alternate wind turbine site, facing west
9
Power Plant
Location (NAD83):60° 51.418’ N, 162° 16.748’ W
Atmautluak Joint Utilities powerhouse, with tank farm in the background
Atmautluak Joint Utilties powerhouse, interior
10
Atmautluak School
Location (NAD83):60° 51.410’ N, 162° 16.611’ W (pedestrian bridge over utilidor near school)
–
Utility pipes outside Atmautluak School
Utility pipes and generator/heat plant outside Atmautluak School
11
Utility pipes and generator/heat plant are outside Atmautluak School
Generator/heat plant area and fuel tank outside Atmautluak School
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Atmautluak Wind-Diesel Feasibility Study
Appendix C: Environmental Review Checklist Memo
The environmental permitting steps below are based on the publication Alaska Wind Energy
Development: Best Practices Guide to Environmental Permitting and Consultations, a study done by the
URS Corporation for the Alaska Energy Authority in 2009.
Alaska Department of Environmental Conservation
Alaska Pollution Discharge Elimination System
State regulations (18 AAC 83 APDES) require that all discharges, including storm water runoff, to surface
waters be permitted under the Alaska Pollutant Discharge Elimination System (APDES) permit program,
which aims to reduce or eliminate stormwater runoff that might contain pollutants or sediments from a
project site during construction. The construction of one or more wind turbines, and the connecting
access road and power line, in Atmautluak would likely disturb one acre or more of soil, and thus must
be permitted under the State of Alaska’s Construction General Permit (CGP) and have a Storm Water
Pollution Prevention Plan (SWPPP).The construction contractor must submit a Notice of Intent (NOI) to
Alaska Department of Environmental Conservation (DEC) before submitting a SWPPP. The DEC issues
the final APDES permit for the project after review and public comment periods.
US Fish and Wildlife Service and National Marine Fisheries Service
Atmautluak is located in an area that is mapped by the Anchorage Fish and Wildlife Field Office as “No
Consultation Necessary” for listed species under the Endangered Species Act. This map is called “ESA
Listed Species Consultation Guide –Anchorage Fish and Wildlife Field Office”. The legend states “If your
project is located within Solid Green on this map, there are no listed species present within your project
area and no consultation is necessary.”
Atmautluak Traditional Council must also be aware of USFWS regulations and guidance under Migratory
Bird Treaty Act, which prohibits the taking of active bird nests, their eggs and young. USFWS has
developed “Bird Windows” statewide that prohibit clearing and construction activity. The bird window
in the Atmautluak area is May 5 to July 25 except for Canada geese and swan habitat where the window
begins April 20 and for black scoter habitat where the window closes August 10. Clearing before or after
these dates is allowed. Clearing and construction activity during the window is not allowed.
2
USFWS Wind Turbine Guidelines Advisory Committee developed guidelines and recommendations for
wind power projects to avoid impacts to birds and bats. These recommendations were sent to the
Secretary of the Interior in March 2010 and should be referred to during design and construction.
Federal Aviation Administration
Determination of No Hazard to Air Navigation-
Atmautluak Traditional Council will be required to file an FAA Form 7460-1 (Notice of Proposed
Construction or Alteration), as the proposed wind turbine site(s) are less than one mile from the
Atmautluak airport. Obstruction lighting on the wind turbine(s) is likely to be required.
Alaska Department of Natural Resources
Alaska Coastal Management Program consistency review -
The Alaska Department of Natural Resources (ADNR)-administered Alaska Coastal Management
Program (ACMP) evaluates projects within the Coastal Zone, which includes Atmautluak, for consistency
with statewide standards and other local Coastal District enforceable policies. The ACMP consistency
review is a coordination process involving all federal and state permitting authorities within the
Ceñaliuriit Coastal Resource Service Area (CRSA), where Atmautluak is located.
The project design consultant will, on behalf of Atmautluak Traditional Council, fill out a Coastal Project
Questionnaire (CPQ) and consistency evaluation form and submit it to ADNR’s Division of Coastal and
Ocean Management (DCOM). After a public comment and review period, DCOM will issue a final
consistency determination.
State Historic Preservation Office (SHPO) consultation-
The project design consultant will complete a consultation under Section 106 of the Historic
Preservation Act with the State Historic Preservation Office (SHPO), to receive a letter concurring that a
wind project would affect no historic properties.
US Army Corps of Engineers
The US Army Corps of Engineers (USACE) requires the placement of fill in “waters of the United States”,
including wetlands and streams, under Section 404 of the Clean Water Act (CWA). Because much or all
of the proposed wind turbine site(s) in Atmautluak are located on wetlands, Atmautluak Traditional
Council must receive a Section 404 permit from the Alaska District USACE.
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Atmautluak Wind-Diesel Conceptual Design/Feasibility Study
Appendix D:HOMER Analysis
Included in this appendix are HOMER Systems Reports for modeling the following two scenarios:
Two NW100 turbines at $5.48/gallon ($1.45/liter) fuel cost
Two V17 turbines at $5.48/gallon ($1.45/liter) fuel cost
Main Assumptions:
$1,725,000 total installed cost for 2-turbine V17 wind system
$2,325,000 total installed cost for 2-turbine NW100 wind system
Annual O&M costs are $10,000 for each wind turbine
2% interest rate
20 year project life
Assumed fuel cost is fixed for the 20-year project, and does not increase.
The annual electric energy consumption of approximately 679,000 kWh (based on Atmautluak’s
2009 generation statistics) is fixed, and does not increase.
Only the two newest existing diesel gensets in the Atmautluak power plant will be used:
o Generator 2 (250 kW)
o Generator 3 (117 kW)
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Atmautluak Wind-Diesel Feasibility Study
Appendix E:Manufacturer-provided Specification Sheets
Northern Power Systems Northwind100 Arctic specification sheet
Vestas V17/90 specification sheet
Bergey BWC EXCEL S turbine specification sheet