HomeMy WebLinkAboutPoint Hope Wind-Diesel Conceptual Design Report - Dec 2014 - REF Grant 7030012Point Hope Wind-Diesel Conceptual
Design Report
12 December 2014
This report prepared for
North Slope Borough
by
and
Point Hope Conceptual Design Report, rev. 3 P a g e | i
This report was written by Douglas Vaught, P.E. of V3 Energy, LLC under contract to WHPacific Solutions
Group for development of wind power in the village of Point Hope, Alaska. This analysis is part of a wind
energy design project for the North Slope Borough and funded by the Alaska Energy Authority.
Contents
Introduction ............................................................................................................................................ 1
Project Management ........................................................................................................................... 1
Executive Summary ................................................................................................................................. 1
Point Hope .............................................................................................................................................. 2
Wind Resource Assessment ..................................................................................................................... 3
Met tower data synopsis ..................................................................................................................... 4
Data Recovery ..................................................................................................................................... 4
Wind Speed ......................................................................................................................................... 4
Wind Rose ........................................................................................................................................... 5
Turbulence Intensity ............................................................................................................................ 6
Extreme Winds .................................................................................................................................... 6
Cold Climate Considerations of Wind Power ........................................................................................ 7
Wind Project Sites ................................................................................................................................... 8
Site A ................................................................................................................................................... 9
Site B ................................................................................................................................................. 10
Site C ................................................................................................................................................. 10
Site D ................................................................................................................................................. 11
Other Site Options ............................................................................................................................. 12
Recommended Site Option ................................................................................................................ 13
Wildlife/Avian Study .............................................................................................................................. 13
Geotechnical Report .............................................................................................................................. 14
Noise Analysis ....................................................................................................................................... 15
Permitting and Environmental Review ................................................................................................... 16
Alaska Pollution Discharge Elimination System .................................................................................. 16
US. Fish and Wildlife Service/National Marine Fisheries Service ......................................................... 16
Federal Aviation Administration ........................................................................................................ 17
U.S. Army Corps of Engineers............................................................................................................. 18
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Alaska Department of Fish and Game ................................................................................................ 18
State Historic Preservation Office ...................................................................................................... 18
Wind-Diesel Hybrid System Overview .................................................................................................... 18
Wind-diesel Design Options ............................................................................................................... 19
Low Penetration Configuration ...................................................................................................... 19
Medium Penetration Configuration ............................................................................................... 19
High Penetration Configuration ..................................................................................................... 20
Recommended Penetration Configuration ..................................................................................... 21
Wind-Diesel System Components ...................................................................................................... 22
Wind Turbine(s) ............................................................................................................................. 22
Supervisory Control System ........................................................................................................... 22
Synchronous Condenser ................................................................................................................ 22
Secondary Load ............................................................................................................................. 23
Deferrable Load ............................................................................................................................. 23
Interruptible Load .......................................................................................................................... 23
Storage Options ............................................................................................................................. 23
Wind-Diesel Philosophy ......................................................................................................................... 24
Point Hope Powerplant ......................................................................................................................... 26
Switchgear ......................................................................................................................................... 27
Geospatial Perspective of Electrical Load ........................................................................................... 27
Phase Balance of Electrical Load ........................................................................................................ 27
Transformers ..................................................................................................................................... 27
Phase and/or Transformer Capacity Location(s) for Additional Load .................................................. 27
Condition of Distribution Lines, Transformers, Poles .......................................................................... 27
Parasitic and Other Losses ................................................................................................................. 28
Wind Turbine Options ........................................................................................................................... 28
Aeronautica AW/Siva 250 .................................................................................................................. 28
EWT DW 54-900 ................................................................................................................................ 29
Northern Power Systems 360-39 (NPS 360-39) .................................................................................. 30
Vestas V39 ......................................................................................................................................... 31
Wind-Diesel HOMER Model ................................................................................................................... 32
Powerplant ........................................................................................................................................ 32
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Caterpillar 3512 Fuel Efficiency ...................................................................................................... 33
Cat 3512 Electrical and Thermal Efficiency ..................................................................................... 33
Cat 3512 Recovered Heat Ratio ...................................................................................................... 34
Wind Turbines ................................................................................................................................... 34
Electric Load ...................................................................................................................................... 35
Thermal Load..................................................................................................................................... 37
Wind Turbine Configuration Options ................................................................................................. 38
System Modeling and Technical Analysis ............................................................................................... 40
Model Results .................................................................................................................................... 41
AW/Siva 250, four (4) turbines, 30 m hub height............................................................................ 41
EWT DW 54-900, one (1) turbine, 35 m hub height ........................................................................ 42
Northern Power NPS 360-39, three (3) turbines, 30 m hub height .................................................. 43
Vestas V39, two (2) turbines, 40 m hub height ............................................................................... 44
Economic Analysis ................................................................................................................................. 45
Fuel Cost ........................................................................................................................................... 45
Wind Turbine Project Costs................................................................................................................ 46
Modeling Results ............................................................................................................................... 47
Data Analysis Uncertainty ...................................................................................................................... 47
Discussion ............................................................................................................................................. 48
Cost ................................................................................................................................................... 48
Reliability........................................................................................................................................... 48
Aesthetics .......................................................................................................................................... 48
Redundancy....................................................................................................................................... 49
Support ............................................................................................................................................. 49
Commonality ..................................................................................................................................... 49
Turbine Recommendation ..................................................................................................................... 49
Single Turbine Option ........................................................................................................................ 51
Wind Turbine Layout ......................................................................................................................... 51
Data Collection Recommendation ......................................................................................................... 52
Project Design Penetration Consideration ............................................................................................. 52
Appendix A – FAA’s Notice Criteria Tool, Site A ........................................................................................ A
Appendix B – FAA’s Notice Criteria Tool, Site B ........................................................................................ B
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Appendix C – FAA’s Notice Criteria Tool, Sites C and D ............................................................................. C
Appendix D – Power Grid, Point Hope .....................................................................................................D
Appendix E – Proposed Power Distribution One-Line Diagram ................................................................. E
Appendix F – Power Distribution System Expansion for Sites B and A....................................................... F
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Introduction
North Slope Borough is the electric utility for the City of Point Hope. In 2009 North Slope Borough
contracted WHPacific to install met towers and perform wind resource assessment analyses in five
Borough communities: Point Hope, Wainwright, Atqasuk, Kaktovik, and Anaktuvuk Pass (a wind resource
assessment was previously completed by U.S. DOE for Point Lay). This was followed in 2011 with a
contract to WHPacific to write feasibility studies for the villages of Point Hope, Point Lay, and
Wainwright. WHPacific subcontracted V3 Energy, LLC to assist with both efforts. In 2013 North Slope
Borough contracted WHPacific Solutions Group to complete the conceptual design phase of the project
in anticipation of Alaska Energy Authority authorizing wind power design projects for the three
communities.
WHPacific Solutions Group has contracted V3 Energy, LLC to re-evaluate the wind resource assessment
and feasibility study for each community, update the power systems modeling with a selection of
appropriate village-scale wind turbines, perform preliminary economic analyses of the proposed
projects, and due to funding constraints, prepare a “light” conceptual design report. This conceptual
design report for the village of Point Hope is a culmination of that effort.
Project Management
The North Slope Borough, Department of Public Works, has executive oversight of this project. North
Slope Borough and the City of Point Hope wish to install wind turbines in Point Hope primarily to reduce
diesel fuel consumption and save money, but also to:
Reduce long-term dependence on outside sources of energy
Reduce exposure to fuel price volatility
Reduce air pollution resulting from reducing fossil fuel combustion
Reduce possibility of spills from fuel transport & storage
Reduce North Slope Borough’s carbon footprint and its contribution to global climate change.
Executive Summary
WHPacific Solutions Group and V3 Energy, LLC recommend the new 360 kW Northern Power System
360-39 wind turbine in a medium penetration mode for a Point Hope wind power project. This
recommendation is based on Northern Power System’s track record and support network in Alaska, the
ability to achieve turbine commonality with all four Borough wind power project communities (Point
Hope, Point Lay, Wainwright, and Kaktovik), and Northern Power System’s factory technical support.
The recommended wind turbine site location is Site B near the airport; chosen for its lower development
cost than alternate sites and its displacement from cultural use areas east of the village.
The reader is cautioned to note that this conceptual design report was prepared as an abbreviated or
“light” version of a typical conceptual design. With that in mind, although turbine choice, site location,
and wind power penetration goals are presented, discussed and/or recommended in this report, further
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conversation and collaboration with North Slope Borough project management, Tikigaq Corporation,
and the community of Point Hope is recommended before the project progresses to detailed design.
Point Hope
Point Hope (Tikeraq) peninsula is one of the oldest continuously occupied locations in Alaska. Several
Inupiat Eskimo settlements have existed on the
peninsula over the past 2,500 years, including more
recently Old and New Tigara, Ipiutak, Jabbertown, and
present Point Hope. The peninsula allows access to
marine mammals and ice conditions enable easy boat
launchings into open leads early in the spring whaling
season. The people were traditionally dominant and
exercised control over an extensive area, from the
Utukok to Kivalina Rivers and far inland. By 1848
commercial whaling activities brought an influx of
Westerners, many of whom employed Point Hope
villagers. By the late 1880s, the whalers established shore-based whaling stations such as Jabbertown.
These disappeared in the early 1900’s with the demise of whaling. The Point Hope city government was
incorporated in 1966. In the early 1970s, the village moved to a new site just east of the old village
because of erosion and periodic storm-surge flooding. Most of the housing was moved on runners to the
new site. New houses were constructed by the borough and individuals.
A federally-recognized tribe is located in the community, the Native Village of Point Hope. Point Hope
residents (Tikeraqmuit Inupiat Eskimos) are dependent upon marine subsistence. This highly favorable
site, with its abundant resources, has enabled the Tikeraqmuit to retain strong cultural traditions after
more than a century of outside influences. The sale, importation, and possession of alcohol are banned
in the village. The Point Hope population of 674 people is approximately 89 percent Alaska Native, five
percent Caucasian, four percent multi-racial, and two percent Hispanic, black or other.
The North Slope Borough provides all utilities in Point Hope. Water is derived from a lake six miles to the
east and is treated and stored in a tank. A number of homes have water tanks with delivery, which
provides running water for kitchens; others haul water. Electricity is provided by North Slope Borough.
There is one school located in the community which has 222 students. Emergency Services have coastal
and air access. Emergency service is provided by 911 Telephone Service volunteers and a health aide
based at the Point Hope Clinic. Auxiliary health care is provided by the Point Hope Volunteer Fire Dept.
Most full-time positions in Point Hope are with the city and borough governments. Residents
manufacture whalebone masks, baleen baskets, ivory carvings, and Eskimo clothing. Seals, bowhead
whales, beluga whales, caribou, polar bears, birds, fish, and berries are utilized.
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Topographic map of Point Hope
Google Earth image of Point Hope
Wind Resource Assessment
The wind resource measured in Point Hope is superior, with measured high wind power class 6
(outstanding). In addition to high annual mean wind speed and wind power density, Point Hope
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experiences highly directional prevailing winds, low turbulence and calculations indicate low extreme
wind speed probability.
A 34 meter met tower, erected to 30 meters, was installed in June 2009 at the northeast corner of Point
Hope between the village water storage tank and a large snow fence to the north. This site was chosen
as it is near the power plant and other existing electrical power infrastructure and did not present
obstruction problems for airport operations. The met tower was removed in July 2010 and a wind
resource assessment report was forwarded to North Slope Borough in August, 2010.
Met tower data synopsis
Data dates June 16, 2009 to July 15, 2010 (13 months)
Wind power class 6 (outstanding)
Power density mean, 30 m 515 W/m2
Wind speed mean, 30 m 7.12 m/s
Max. 10-min wind speed average 27.9 m/s
Maximum wind gust 32.2 m/s (Dec. 2009)
Weibull distribution parameters k = 1.82, c = 7.92 m/s
Wind shear power law exponent 0.110 (low)
Roughness class 0.27 (rough sea)
IEC 61400-1, 3rd ed. classification Class III-c (lowest defined and most common)
Turbulence intensity, mean 0.073 (at 15 m/s)
Calm wind frequency 20% (<3.5 m/s)
Data Recovery
Met tower data recovery in Point Hope was outstanding, with nearly 100 percent functionality of the
anemometers, wind vane and temperature sensor. This is remarkable anywhere in Alaska, but even
more so on the Chukchi Sea coast of the North Slope with its intensely cold winter temperatures.
Wind Speed
Wind data collected from the met tower, from the perspective of both mean wind speed and mean
power density, indicates an outstanding wind resource. The minor discrepancy in mean wind speed
between the 30 m A and the 30 m B anemometer is due to the placement of the of the 30 m A
anemometer at 178° T. With frequent northerly winds, the 30m A anemometer experienced some
minor tower shadowing effects. The cold arctic temperatures of Point Hope contributed to the high
wind power density, a key consideration of wind turbine performance.
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Wind speed profile
Wind Rose
Wind frequency rose data indicates highly directional winds from the north and southeast. Power
density rose data (representing the power in the wind) indicates power winds are strongly directional,
from 345°T to 025°T and to a lesser extent from 130°T. Calm frequency (percent of time that winds at
the 30 meter level are less than 3.5 m/s) was 20 percent during the met tower test period.
Wind frequency rose Wind energy rose
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Turbulence Intensity
Turbulence intensity at the Point Hope test site is well within acceptable standards with an IEC 61400-1,
3rd edition (2005) classification of turbulence category C, which is the lowest defined. Mean turbulence
intensity at 15 m/s is 0.073.
Turbulence graph
Extreme Winds
Although thirteen months of data is minimal for calculation of extreme wind probability, use of a
modified Gumbel distribution analysis, based on monthly maximum winds vice annual maximum winds,
yields reasonably good results. Extreme wind analysis indicates a desirable situation in Point Hope: high
mean wind speeds combined with low extreme wind speed probabilities. This may be explained by
particular climactic aspects of Point Hope which include prominent coastal exposure, offshore wind
conditions, and due to the extreme northerly latitude, lack of exposure to Gulf of Alaska or other sub-
tropical-origin storm winds.
Industry standard reference of extreme wind is the 50 year, 10-minute average probable wind speed,
referred to as Vref. For Point Hope, this calculates to 36.8 m/s, below the threshold of International
Electrotechnical Commission (IEC) 61400-1, 3rd edition criteria (of 37.5 m/s) for a Class III site. Note that
Class III extreme wind classification is the lowest defined and all wind turbines are designed for this wind
regime. For the design phase of the project, however, the wind data should be re-examined by the
turbine manufacturer to ensure turbine IEC classification suitability.
Point Hope met tower Gumbel distribution of extreme wind
Vref Gust IEC 61400-1, 3rd ed.
Period (years)(m/s) (m/s) Class Vref, m/s
2 27.2 32.4 I 50.0
10 32.0 38.2 II 42.5
15 33.2 39.6 III 37.5
30 35.3 42.1 S
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Vref Gust IEC 61400-1, 3rd ed.
Period (years)(m/s) (m/s) Class Vref, m/s
50 36.8 43.9
100 38.9 46.4
average gust factor:1.19
The complete V3 Energy, LLC wind resource assessment report of Point Hope is forwarded with this
conceptual design report.
Cold Climate Considerations of Wind Power
Point Hope’s harsh climate conditions is an important consideration should wind power be developed in
the community. The principal challenges with respect to turbine selection and subsequent operation is
severe cold and icing. Many wind turbines in standard configuration are designed for a lower operating
temperature limit of -20° C (-4° F), which clearly would not be suitable for Point Hope, nor anywhere in
Alaska. A number of wind turbine manufacturers offer their turbine in an “arctic” configuration which
includes verification that structural and other system critical metal components are fatigue tested for
severe cold capability. In addition, arctic-rated turbines are fitted with insulation and heaters in the
nacelle and power electronics space to ensure proper operating temperatures. With an arctic rating,
the lower temperature operating limit generally extends to -40° C (-40° F). On occasion during winter
Point Hope may experience temperatures colder than -40° C, at which point the wind turbines would
shut down. Temperatures below -40° C are relatively infrequent however and when they do occur, are
generally accompanied by calm or light winds.
A second aspect of concern regarding Point Hope’s arctic climate is icing conditions. Atmospheric icing
is a complex phenomenon characterized by astonishing variability and diversity of forms, density, and
tenacity of frozen precipitation, some of which is harmless to wind turbine operations and others highly
problematic. Although highly complex, with respect to wind turbines and aircraft five types of icing are
recognized: clear ice, rime ice, mixed ice, frost ice, and SLD ice
(www.Wikipedia.org/wiki/icing_conditions).
Clear ice is often clear and smooth. Super-cooled water droplets, or freezing rain, strike a
surface but do not freeze instantly. Forming mostly along the stagnation point on an airfoil, it
generally conforms to the shape of the airfoil.
Rime ice is rough and opaque, formed by super-cooled drops rapidly freezing on impact. Often
"horns" or protrusions are formed and project into the airflow.
Mixed ice is a combination of clear and rime ice.
Frost ice is the result of water freezing on unprotected surfaces. It often forms behind deicing
boots or heated leading edges of an airfoil and has been a factor airplane crashes.
SLD ice refers to ice formed in super-cooled large droplet (SLD) conditions. It is similar to clear
ice, but because droplet size is large, it often extends to unprotected parts of a wind turbine (or
aircraft) and forms large ice shapes faster than normal icing conditions.
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SLD ice on an airplane
Wind Project Sites
As part of the 2011 feasibility study, North Slope Borough requested that two wind turbine sites be
identified in Point Hope. On July 7 and 8, 2011, Ross Klooster of WHPacific, Doug Vaught of V3 Energy,
LLC, and Max Ahgeak of North Slope Borough Public Works Dept. traveled to Point Hope and met with
Village of Point Hope and Tikigaq Corporation representatives to discuss the wind power project and to
identify the two sites. This was accomplished by reviewing maps and ownership records and then
driving and walking to a number of locations near the village to assess suitability for construction and
operation of wind turbines.
Identifying suitable wind turbine sites in Point Hope proved somewhat difficult due to complicated land
ownership with many native allotments near the village, airport-related air traffic operations limitations,
and cultural and traditional land use considerations that would be incompatable with wind turbine
construction and operation. Two sites on Tikigaq Corporation land were eventually chosen, identified as
Site A and Site B. Site A is located on the isthmus between the village and the mainland, and Site B is
located between the village and the airport at the tip of the peninsula. Both sites are identified in the
Google Earth image below.
Later conversations between Ross Klooster of WHPacific and Price Leavitt of North Slope Borough
identified Site C along the beach strand but closer to the village than Site A. Site D is located north of
the strand access road and can be considered a variation of Site C. Both sites are on Tikigaq Corporation
property.
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Point Hope site options
Site A
Site A, at 4.25 km (2.6 miles) from the village, is perhaps further than ideal given that new power
distribution lines must be constructed the entire distance to this site. However, it is the location on the
strand preferred by village leadership as it avoids traditional use areas and Native allotments. The Site A
parcel is land owned by Tikigaq Corporation, appears to be largely free of permafrost but is somewhat
constrained in size. A key advantage of Site A is that turbine height up to 200 ft. above ground level
(AGL) is unrestricted from an FAA perspective (refer to Appendix A).
Point Hope Site A
PHO Site B
PHO Site A
Site A
PHO Site C
PHO Site D
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Site B
Site B is west of Point Hope near the airport and very near existing 3-phase power distribution lines. The
Site B parcel is land owned by Tikigaq Corporation, is large enough to accommodate several wind
turbines and is presumed to be permafrost-free. This site would be the least costly to develop due to
minimal extension of power distribution and is not near traditional and cultural use areas, although the
community cemetery is relatively nearby. But, the site is near the airport and may be height restricted.
The FAA notice criteria tool (requested at 200 ft. AGL) indicates possible navigation signal reception
interference (refer to Appendix B), but likely this is a resolvable problem.
Point Hope Site B
Site C
Site C is east of the village but closer than Site A. This site is located south of the strand road between a
smaller Native Allotment to the west and continuous block of several larger Allotments to the east. Site
C is larger than Site A and more turbines could be sited as this location. A possible drawback however is
proximity to traditional and cultural use areas on the Chukchi Sea beach. The FAA notice criteria tool
(requested at 200 ft. AGL) indicates possible navigation signal reception interference (refer to Appendix
C), but less than at Site B and very likely a resolvable issue.
Site B
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Point Hope Site C
Site D
Site D is immediately north of Site C on the north side of the strand access road. This site has an
advantage of displacement from traditional and cultural use areas compared to Site C and also presents
a long east-to-west alignment which is advantageous for siting wind turbines with Point Hope’s
predominant northerly winds. As with Site C, Site D is larger than Site A and more turbines could be
sited as this location. Same as for Site C, the FAA notice criteria tool (requested at 200 ft. AGL) indicates
possible navigation signal reception interference (refer to Appendix C), but less than at Site B and very
likely a resolvable issue.
Point Hope Site D
Site C
Site D
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Point Hope wind turbine site options table
Site Advantages Disadvantages
A Tikigaq Corp. land
Site large enough to accommodate
up to three wind turbines
Short new access from strand road
Unrestricted turbine height
Likely dry site and good geotech
conditions
4.0 km (2.5 mi) of new distribution
line required; route traverses
several Native Allotments;
existence of utility easement along
road unkonwn
Constrained site (only 1,000 ft.
east-to-west); future expansion
likely not possible due to Native
Allotments east and west
B Tikigaq Corp. land
Very short (~1,000 ft) new
distribution line to existing 3-phase
power serving the airport
Short new access road; minimal cost
Large site able to accommodate
several wind turbines; sufficient
room for future expansion
Dry site; likely good geotech
conditions for turbine foundations
Removed from traditional and
cultural use areas
No Native Allotment space
restrictions
Proximity to the airport; possible
navigation signal interference;
possible high hub height limitation
(note a 2011 FAA determination
noted 158 ft. acceptable with no
further review)
Near the community cemetery
(approx. 1,500 ft.)
C Tikigaq Corp. land
Short new access road; minimal cost
Dry site; likely good geotech
conditions
Site larger than Site A with room for
future expansion
1.4 km (0.9 mi) of new distribution
line required
Possible airport navigation signal
interference for very high hub-
height wind turbines
Possibly too near traditional and
cultural use areas on the beach
D Tikigaq Corp. land
Very short new access road(s);
minimal cost
Dry site; likely good geotech
conditions
Site larger than Site A with extensive
room for future expansion
Possible airport navigation signal
interference for very high wind
turbines
Possibly too near traditional and
cultural use areas on the beach,
but further than Site C
Other Site Options
Other than locating wind turbines at the met tower site, which would be too close to the village and not
recommended, Sites A, B, C and D represent the best site options for a wind power project in Point
Hope. Land further east of Site A is possible of course, but one must go a considerable distance to avoid
Native Allotments constraints. For this, there would be no wind energy benefit and a considerable
financial penalty to construct power distribution and an access road across undeveloped marshy tundra.
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Recommended Site Option
WHPacific Solutions Group and V3 Energy, LLC recommend Site B as the preferred site option for a wind
turbine project in Point Hope, presuming a satisfactory FAA obstruction determination can be obtained
(based on the 2011 study, this is likely for lower hub height turbines of approx. 30 meters). This
recommendation is based on lowest construction cost due to very short new distribution required to
connect the turbines to the existing grid, avoidance of traditional and cultural use areas on the strand
east of the community, and placement of wind turbines near an existing developed area (the airport and
the community tank farm).
WHPacific Solutions Group and V3 Energy, LLC note however that Tikigaq Corp. leadership has indicated
Site A as the preferred site option for a wind power project. Site A is unrestricted with respect to
turbine height, which is advantageous, but it would be the most expensive to develop (by a considerable
margin compared to Site B due to 2.5 additional miles of new power distribution line compared to Site
B). Also, Site A is the most constrained with respect to number of turbines possible and hence would
severely limit or possibly preclude future wind power expansion.
Wildlife/Avian Study
North Slope Borough commissioned ABR, Inc. of Fairbanks, Alaska to summarize the biological resources
of Point Hope, including both plant and animal species, to support the wind project development effort.
ABR’s work is documented in a report titled: Site Characterization and Avian Field Study for the Proposed
Community-Scale Wind Project in Northern Alaska.
The ABR study states: The objectives of the Site Characterization Study (SCS) were to: (1) compile and
review existing land cover map products to prepare generalized land cover maps; (2) characterize the
biological resources present; (3) summarize the potential exposure of biological (particularly avian)
resources to impacts; and (4) identify field studies to identify site-specific risks to biological resources
(particularly birds). The objectives of the field studies conducted in 2013 were to: (1) describe temporal
and spatial patterns of habitat use of all birds within and near proposed wind-sites; and (2) provide a
summary of the exposure of focal species to collision risk at each proposed site. This final report
summarizes the SCS and field data to describe the relative exposure of the focal species to the proposed
wind-energy development at the 3 villages.
An excerpt from ABR’s report: “In Point Hope, Site A is located on a narrow part of the peninsula and has
large water bodies to both the north (Marryat Inlet) and south (Chukchi Sea). We found both nesting
and brood-rearing birds in the small ponds west of the site. Most of the bird movements around Site A
were east–west along the northern and southern coastlines. Site B is farther from small ponds and
coastlines that focus bird movements, but it is closer to the point of the peninsula. Birds may fly over the
tip of the peninsula rather than around it, especially during inclement weather (when the exact tip of
the peninsula would be difficult to see), thereby increasing their risk of collision with turbine structures.
Nonetheless, the probability of interaction probably is higher at Site A because of the short distances
between the site and the water bodies. Based on an evaluation of the habitat at both locations and the
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recorded bird movements at Site A (but not Site B), we may expect Site B to have fewer avian issues
with the proposed development.”
The reader is cautioned that the ABR report is complex and that the preceding paragraph does not
adequately summarize ABR’s conclusions; it is included in this CDR for reference only. The reader is
strongly encouraged to consult the ABR report for a complete understanding the plant and wildlife
species of concern and potential impacts of a wind project in Point Hope.
The complete ABR, Inc. site characterization and avian field study report of the proposed Point Hope
wind farm is forwarded with this conceptual design report.
Geotechnical Report
WHPacific commissioned Golder Associates of Anchorage, Alaska to perform a non-field study
assessment of likely geotechnical conditions in Point Hope, Point Lay, and Wainwright in order to
identify potential hazards and provide conceptual foundation recommendations for the proposed wind
tower sites in the three communities. Golder’s work is documented in a report titled: Geotechnical
Review and Feasibility Studies for Wind Turbines: Point Hope, Point Lay, and Wainwright, Alaska, dated
January 27, 2012.
The Golder report states the following regarding Point Hope: The village is located on a gravel spit
extending to the west about 6 miles from the tundra mainland. The spit is bordered by the Chukchi Sea
and has been formed by long shore currents moving along the shoreline. The gravel spit is about 4000
feet wide and consists of a series of beach ridges and intervening swales that parallel the axis of the spit
to about elevation 14 feet on the north side. The swales between the beach lines are 2 feet to 4 feet
lower than the tops of the ridges.
The spit is actively eroding from the west and aggrading on south. North of the village, near the border
with Marryat Inlet, alluvial deposits of stratified silt and sand with peat and tundra vegetation are
typical. Polygonal ice wedge terrain is evident from aerial photography along the southern shore of
Marryat Inlet. In the 1970s, erosion along the northwest beach of the spit, measured at 8.8 feet per
year, prompted the village to move. By the late 1970s, the majority of the village has moved eastward
on the spit approximately 2 miles, bringing it to its current location. The village is currently located near
the center of the spit in an area that has been leveled by filling the beach troughs with fill material. The
village area is un-vegetated, but the troughs of the old beach lines reportedly had thin organic deposits
before that were covered by fill.
The permafrost conditions are unique at the proposed Northwind 100 tower location in Point Hope.
While permafrost is present, it is typically ice poor - a condition where ice is not present in concentrations
exceeding thawed state saturation and individual sand and gravel particles have grain-to-grain contact
in the permafrost. If permitted to thaw, the permafrost will generally experience thaw strains based on
ice to water phase change volumes, but thaw strains in ice-poor materials generally do not exceed the
volumetric change due to ice/water phase change. Seasonal frost heave is generally low in this area,
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primarily related to the coarse-grained nature of the in-place soil. In general, the granular soils at Point
Hope are considered non-frost susceptible.
Accordingly, many structures in Point Hope are founded on post and pad or at-grade foundation with or
without passive subgrade cooling and rigid insulation.
A site-specific geotechnical exploration is required for turbine foundation system. However, based on
nearby geotechnical data, it may be possible to use a concrete or steel frame mat foundation system for
this site. The mat foundation can be founded on the prepared in-place granular soils but a structural fill
section between the foundation and the in-place soil should be considered.
Structural fill should be Alaska Department of Transportation and Public Facilities (ADOT&PF) sub-base
A or similar material. Rigid insulation under the mat foundation should also be considered. If used, the
rigid insulation should have a compressive strength suitable for the design loads, both sustained and
transient. Fill should be placed and compacted in a thawed state. Structural fill should be placed in
nominal one foot thick lifts compacted to at least 95 percent of maximum dry density as determined by
the modified Proctor test method.
A mat foundation system will rely solely on gravity to resist overturn and uplift loads, which may be
considerable with the Northwind 100 turbine systems. The civil and structural design will determine the
depth of excavation and fill requirements above the mat foundation. Mat foundation embedment
depths on the order of 10 to 12 feet may be necessary to develop adequate overturning and uplift
resistance.
Passive subgrade cooling may be required under the mat foundation. If so, Arctic Foundations, Inc. (AFI)
Flat Loop passive subgrade cooling may be considered. The AFI Flat Loop passive subgrade cooling
system may be installed within the structural fill.
Subgrade cooling will provide several engineering advantages. Thaw into the underlying soil will be
limited reducing the volumetric ice to water thaw strain discussed above. If frozen throughout the
project design life, the underlying soil will have a greater allowable bearing capacity and stiffness relative
to thaw state conditions.
The complete Golder Associates geotechnical review report of the proposed Point Hope wind farm is
forwarded with this conceptual design report.
Noise Analysis
As part of a 2007 Powercorp Alaska, LLC Preliminary Wind Feasibility Report of Kaktovik, Point Hope and
Point Lay, Michael Minor & Associates of Portland, Oregon was commissioned to complete a desktop
analysis of the expected noise impact of wind turbines at Site A (this was the only site considered at that
time). This work was documented in a report titled: Noise Analysis Memorandum of the Point Hope
Wind Farm, dated October 14, 2007.
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The noise analysis memorandum summary stated: This project will install a wind turbine generator farm
outside of Point Hope, Alaska. The project proposes to use one Vestas V47, four Vestas V27’s, or one
Führländer 600 wind turbine generator(s). The wind turbine nearest to the eastern edge of town will be
located approximately 3,400 feet to the west. Noise due to the operation of the wind turbines is
expected to be audible in the town, although the overall noise levels are low and are not projected to
exceed 31 to 34 dBA. In addition, the noise from the wind turbines should not exceed the ambient by
more than 1 to 5 dBA except in extreme cases accompanied by high winds, low ambient noise levels and
frozen ground.
The complete Michael Minor & Associates noise analysis memorandum of a Point Hope wind farm is
forwarded with this conceptual design report.
Permitting and Environmental Review
The environmental permitting requirements listed below are discussed in Alaska Wind Energy
Development: Best Practices Guide to Environmental Permitting and Consultations, a study prepared by
URS Corporation for the Alaska Energy Authority in 2009.
Alaska Pollution Discharge Elimination System
State regulations (18 AAC 83) require that all discharges to surface waters, including storm water runoff,
be permitted under the Alaska Pollution Discharge Elimination System (APDES). The goal of the program
is to reduce or eliminate pollution and sediments in stormwater and other discharges to surface water.
Under the state APDES program, projects that disturb one or more acre of ground are subject to the
terms of the Alaska Construction General Permit (CGP) and are required to develop a project Storm
Water Pollution Prevention Plan (SWPPP) outlining measures to control or eliminate pollution and
sediment discharges. The proposed projects in Point Hope, Point Lay and Wainwright are likely to
disturb more than one acre of ground during the construction of proposed wind turbines, supporting
infrastructure and access roads and would be subject to the requirements of the CGP. Prior to
construction, the contractor would be required to file a Notice of Intent (NOI) with the Alaska
Department of Environmental Conservation (ADEC) prior to submitting the project SWPPP. ADEC would
issue an APDES permit following the public comment period.
US. Fish and Wildlife Service/National Marine Fisheries Service
Both the U.S. Fish and Wildlife Service (USFWS) and the National Marine Fisheries Service (NMFS) list
Threatened and Endangered (T&E) that may occur in the vicinity of Point Hope, Point Lay, and
Wainwright, Alaska. T&E species listed by the USFWS in the vicinity of the project area may include the
short tailed albatross, polar bear, Steller’s eider, spectacled eider. Candidate species that may be found
in the area include the yellow billed loon, Kittlitz’s murrelet, and the Pacific walrus. While NMFS lists
marine T&E species, the bearded seal and ring seal may haul on beaches in the vicinity of the project
area. A discussion with the USFWS will be initiated, and at a minimum, a letter and a map will be sent
requesting their opinion regarding the level of consultation needed to proceed with the construction of
the project.
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USFWS regulations and guidance under the Migratory Bird Treaty Act prohibits the taking of active bird
nests, eggs and young. In their Advisory: Recommended Time Periods for Avoiding Vegetation Clearing
in Alaska in order to protect Migratory Birds, USFWS has developed “bird windows” statewide that
prohibit clearing activity. The bird window for the Northern region of Alaska, including the communities
of Point Hope, Point Lay and Wainwright is June 1st – July 31st for shrub and open type habitats (tundra
and wetlands) and May 20th – September 15
th for nesting seabird colonies. The clearing window for
black scoter habitat is through August 10th. Clearing prior to these dates is allowed. If clearing has
already occurred then construction may proceed during these dates.
USFWS Wind Turbine Guidelines Advisory Committee developed guidelines and recommendations for
wind power projects to avoid impacts to birds and bats. These recommendations have been released to
the public as draft U.S. Fish and Wildlife Service Land-Based Wind Energy Guidelines and will be referred
to during design and construction of a wind turbine project in Point Hope, Point Lay and Wainwright.
In February 2014, ABR Inc. completed a report prepared for the North Slope Borough titled “Site
Characterization and Avian Field Study for the Proposed Community-Scale Wind Project in Northern
Alaska”. The study was for the communities of Point Hope, Point Lay and Wainwright. The ABR study
characterized habitat, bird abundance, migration and nesting movements of observed species and
analysis of the impacts on species of concern, specifically spectacled eiders (endangered), Steller’s
eiders (endangered) and yellow-throated loons (threatened). The site characterization was focused on a
one-mile radius study area surrounding each of the proposed turbine locations in each of the
communities. The study concluded that both the most abundant bird species and those with limited
populations like the Steller’s and spectacled eiders are most at risk from wind infrastructure. The ABR
report states impacts to Steller’s eiders should be considered in all three project areas. Spectacled eiders
were not recorded near any of the proposed turbine locations and concluded the risk to this species are
low. Yellow billed loons, a USFWS species of concern, were active in Point Hope, were active to a lesser
extent in Point Lay, and not recorded in Wainwright. Red throated loons, which is a BLM Alaska Natural
Heritage Program “watch” species, were absent from Point Hope but were observed in Point Lay and
Wainwright. Red throated loons were the most observed among the focal species discussed in the
report and were often observed flying low, below the rotor swept area (RSA). The report concludes that
post-construction monitoring data suggests wind infrastructure operates in rural Alaska with limited
direct impacts to bird species; however, some impacts would be expected due to migration and
breeding movements. Turbine selection and temporal adjustments to operation could mitigate
potential impacts.
Federal Aviation Administration
Prior to turbine construction an FAA Notice of Proposed Construction or Alteration (Form 7460-1) is
require to be completed. Filing a 7460-1 may result in additional discussions with the FAA regarding
turbine siting and appropriate lighting requirements that would need to be incorporated into the project
specifications.
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U.S. Army Corps of Engineers
The US Army Corps of Engineers (USACE) requires a permit for the placement of fill in “waters of the
United States”, including wetlands and streams, under Section 404 of the Clean Water Act (CWA). The
proposed wind turbine site(s) and supporting infrastructure in Point Hope, Point Lay and Wainwright
may be all, or partially located on wetlands. The project must receive a Section 404 permit from the
Alaska District USACE and an accompanying U.S. Environmental Protection Agency (EPA) Section 401
Water Quality Certification if the project is situated on, or will impact waters of the US. Currently,
Individual Permits and Nationwide 12 permits are being issued for wind power projects in Alaska. An
individual permit would be required for activities related to the construction of access roads or pads in
wetlands. A Nationwide 12 Permit would be appropriate for activities related to utility installation (i.e.
power lines). Depending on the site selection and potential impacts, a jurisdictional determination
(wetland delineation) may be necessary to obtain a Section 404 permit.
Alaska Department of Fish and Game
The Alaska Department of Fish and Game (ADF&G) oversees activities that may have an impact on fish
habitat and anadromous fish streams. An ADF&G Title 16 Fish Habitat Permit would be required if the
proposed project includes construction of access roads and infrastructure that may impact fish habitat
or would involve installing a culvert in a fish stream.
State Historic Preservation Office
Consultation with the State Historic Preservation Office (SHPO) for State of Alaska-funded projects is
required under the State Historic Preservation Act. The act requires that all state projects be reviewed
for potential impacts to cultural and historic resources. During the permitting phase of the project prior
to construction, consultation with the SHPO would be initiated to determine if the project may impact
these resources. The extent of needed infrastructure (pads and new roads) and the presence of known
archaeological sites in the vicinity of the project area may trigger the SHPO to recommend an
archaeological survey of the site.
Wind-Diesel Hybrid System Overview
There are now over twenty-four wind-diesel projects in the state, making Alaska a world leader in wind-
diesel hybrid technology. There are a variety of system configurations and turbine types in operation
and accordingly there is a spectrum of success in all of these systems. As experience and statewide
industry support has increased so has overall system performance. The following figure illustrates the
locations of installed wind projects in Alaska.
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Alaska wind-diesel projects
Wind-diesel Design Options
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, medium, and high; occasionally
very low is also defined as a category. Wind penetration level is roughly equivalent to the amount of
diesel fuel displaced by wind power. Note however a positive correlation of system control and
demand-management strategy complexity with wind power penetration.
Low Penetration Configuration
Low (and extremely low) penetration wind-diesel systems require the fewest modifications to the
existing system. However, they tend to be less economical than higher penetration configurations due
to the limited annual fuel savings compared to fixed project costs, such as new distribution connection.
Medium Penetration Configuration
Medium penetration wind-diesel requires relatively sophisticated power quality control due to
occasional circumstance of wind generation exceedingload demand and generally are with a full-time
diesels-on requirement. Medium penetration is often chosen as a compromise between the minimal
benefit of low penetration and the considerable complexity of high penetration, but experience has
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indicated that this may be misleading. Power quality can be difficult to maintain with typical medium
penetration configuration design and upgrades necessary to improve power quality control edge enough
toward high penetration that the greater economic benefits of high penetration wind are not captured
due to insufficient wind turbine capacity.
High Penetration Configuration
High penetration configuration design typically enables diesels-off operation and uses a significant
portion of the wind energy for thermal heating loads. The potential benefit of high penetration can be
significant, but system complexity requires a significant investment in project commissioning, operator
training, and strong management practices.
Wind-diesel penetration level are summarized table below in a table developed by Alaska Energy
Authority. Note that instantaneous penetration level is much more important for system configuration
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design than average penetration. One way to appreciate instantaneous penetration and design is to
think of an automobile: the brakes are designed for the maximum (or instantaneous) vehicle speed of,
say, 120 mph, not the vehicle’s typical day-to-day average speed of 45 mph. If the brakes were designed
for average vehicle speed, one would be unable to stop when driving at highway cruising speeds, let
alone maximum vehicle speed!
The annual contribution of wind energy, expressed as percentage of wind energy compared to load
demand, is the average penetration level. This defines the economic benefit of a project.
Categories of wind-diesel penetration levels
Penetration
Category
Wind Penetration Level
OperatingCharacteristicsandSystem RequirementsInstantaneousAverage
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
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
Recommended Penetration Configuration
In general, medium penetration is a good design compromise as it enables a relatively large amount of
displaced fuel usage but requires only a moderate degree of system complexity. Medium penetration is
the preferred system configuration of Alaska Village Electric Cooperative (AVEC), owner and operator of
eleven wind-diesel systems statewide, and Alaska’s leading utility developer of wind-diesel. AVEC’s
experience provides a useful guide for North Slope Borough as it develops wind energy for its
communities.
It should be noted however that not all world-wide designers categorize wind penetration as does
Alaska Energy Authority. Many collapse the penetration categories to just two: low and high. This
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simplification is in recognition that system design is dependent on the percentage of instantaneous, not
average penetration. The nuances beyond that are diesels-off capability and inclusion of storage
options. For village wind power, a project capable of off-setting a worthwhile amount of diesel fuel and
providing real economic benefit to the community invariably must be high penetration by the alternate
definition. With this in mind, limiting average penetration to a compromise level of 20 to 50 percent
may, in some respects, make very little sense. With a design configuration capable of controlling 100
percent and higher instantaneous penetration, there is no particular reason to limit average penetration
to a pre-determined percentage as with Alaska Energy Authority’s definition of medium penetration.
Wind-Diesel System Components
Listed below are the main components of a medium to high-penetration wind-diesel system:
Wind turbine(s), plus tower and foundation
Supervisory control system
Secondary load (plus controller)
Deferrable load
Interruptible load
Storage
Synchronous condenser
Wind Turbine(s)
Village-scale wind turbines are generally considered to be 50 kW to 500 kW rated output capacity. This
turbine size once dominated with worldwide wind power industry but has long been left behind in favor
of much larger 1,500 kW plus capacity turbines. Conversely, many turbines are manufactured for home
or farm application, but generally these are 10 kW capacity or less. Consequently, few new 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 repowering older wind farms in the 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 Point
Hope 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.
Synchronous Condenser
A synchronous condenser, also referred to as a synchronous compensator, is a specialized synchronous-
type 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 grid voltage or to maintain
the grid power factor at a specified level. A synchronous condenser or similar device is needed to
operate in diesels-off mode with wind turbines equipped with asynchronous (induction) type
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generators. This is to provide the reactive power necessary for operation of the asynchronous
generator.
Secondary Load
A secondary or “dump” load during periods of high wind is required for a wind-diesel hybrid power
system to operate reliably and economically. The secondary load converts excess wind power into
thermal power 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. 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, could be installed in Point Hope to
absorb excess instantaneous energy (generated wind energy plus minimum diesel output exceeds
electric load demand). 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.
Interruptible Load
Electric heating either in the form of electric space heaters or electric water boilers could 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 40 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 for information but are not currently part of the overall system design,
philosophy, although could be should NSB wish to consider high wind penetration options.
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Flywheel
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. The smallest
capacity flywheel available from Powercorp (now ABB), however, is 500 kW capacity, so it is only
suitable for large village power generation systems.
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 a July, 2009 Alaska Center for Energy and Power 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, NiCad’s are considerably more expensive than
lead-acid batteries, experience a shorter operational life (approx. 5 years vs. 20 years for lead-acid) and
one must note that the Wales wind-diesel system had a poor operational history with NiCad batteries
and has not been functional for a number of 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
power. Following some design and commissioning delays, the solid state converter system in Kokhanok
should be operational by early 2015 and will be monitored closely for reliability and effectiveness.
Wind-Diesel Philosophy
Installing wind turbines and creating a wind-diesel power system in an Alaskan village is a demanding
challenge. At first glance, the benefits of wind power are manifest: the fuel is free and it is simply a
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manner of capturing it. The reality of course is more complicated. Wind turbines are complex machines
and integrating them into the diesel power system of a small community is complicated. With wind-
diesel, a trade-off exists between fuel savings and complexity. A system that is simple and inexpensive
to install and operate will displace relatively little diesel fuel, while a wind-diesel system of considerable
complexity and sophistication can achieve very significant fuel savings.
The ideal balance of fuel savings and complexity is not the same for every community and requires
careful consideration. Not only do the wind resource, electric and thermal load profiles, and
powerhouse suitability vary between villages, so does technical capacity and community willingness to
accept the opportunities and challenges of wind power. For reasons that go beyond design and
configuration questions, a very good wind-diesel solution for one village may not work as well in another
village. Ultimately, the electric utility and village residents must consider their capacity, desire for
change and growth, and long-term goals when deciding the best solution to meets their needs.
The purpose of this conceptual design report is to introduce and discuss the viability of wind power in
Point Hope. As discussed, many options are possible, ranging from a very simple low penetration
system to a highly complex, diesels-off configuration potentially capable of displacing 50 percent or
more of fuel usage in the community. It is possible that North Slope Borough and Point Hope residents
ultimately will prefer a simple, low penetration wind power system, or alternatively a very complex high
penetration system, but from past discussions and work it appears that a moderate approach to wind
power in Point Hope is preferable, at least initially.
With a moderately complex project design framework in mind, a configuration of relatively high wind
turbine capacity with no electrical storage and no diesels-off capability was chosen. This provides
sufficient wind capacity to make a substantive impact on fuel usage but does not require an abrupt
transition from low to high complexity. Although conceptually elegant, there is a trade-off to consider
with this approach. Installing a large amount of wind power (900 to 1,000 kW of wind capacity is
recommended) is expensive, but without electrical or thermal storage some of the benefits of this wind
power capacity may not be used to best advantage.
The thermodynamics of energy creation and use dictates that wind power is more valuable when used
to offset fuel used by diesel generators to generate electricity than fuel used in fuel oil boilers to serve
thermal loads. Referring to the energy production summaries for the turbine configurations under
Modeling Results, one can see that the wind turbines are expected to produce relatively small amounts
of excess electricity, even at 85 percent turbine availability. This excess electricity, although minimal,
must be shunted via a secondary load controller to the diesel generator heat recovery loop or simple
radiation heaters to avoid curtailing wind turbines during periods of high wind and relatively light
electrical load.
Although perhaps not readily apparent in the report, this compromise of wind capacity versus
complexity is contained within the economic benefit-to-cost tables. This compromise, which is endemic
to wind-diesel, results in high capital costs, but usage of the energy generated is imperfect from an
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efficiency point of view. The most efficient usage of wind energy from a technical point of view – offset
of electrical power, may be too expensive from a cost-benefit perspective.
It is important not to focus strictly on benefit-to-cost ratio of a particular configuration design or
particular turbine option, but also consider a wider view of the proposed wind project for Point Hope.
Installing approximately 900 kW capacity of wind power has considerable short-term benefit with
reduction of diesel fuel usage, but more importantly it would provide a platform of sustainable
renewable energy growth in Point Hope for many years to come. This could include enhancements such
as additional thermal load offset, battery storage and/or use of a flywheel to enable diesels-off
capability, creation of deferred heat loads such as water heating, and installation of distributed electrical
home heat units (Steffes heaters or similar) controlled by smart metering. The latter, presently
operational to a limited extent in the villages of Kongiganak, Kwigillingok, Tuntutuliak, has enormous
potential in rural Alaska to not only reduce the very high fuel oil expenses borne by village residents, but
also to improve the efficiency and cost benefit of installed and future wind power projects. These
opportunities and benefits are tangible and achievable, but their cost benefit was not modeled in this
report.
Lastly, it must be acknowledged that a wind power project in Point Hope will provide benefits that are
not easily captured by economic modeling. These are the externalities of economics that are widely
recognized as valuable, but often discounted because they are considered by some as soft values
compared to the hard numbers of capital cost, fuel quantity displaced, etc. These include ideals such as
long-term sustainability of the village, independence from foreign-sourced fuel, reduction of Point
Hope’s carbon footprint, and opportunities for education and training of local residents. Beyond these
somewhat practical considerations, there is the simple moral argument that renewable energy is the
right thing to do, especially in a community such as Point Hope that is in the vanguard of risk from rising
sea level due to global warming.
Point Hope Powerplant
Electric power (comprised of the diesel power plant and the electric power distribution system) in Point
Hope is provided by North Slope Borough Public Works Department, the utility for all communities on the
North Slope, with the exception of Deadhorse and Barrow. The existing power plant in Point Hope
consists of four Caterpillar 3512 diesel generators, two rated at 665 kW and one rated at 950 kW output.
North Slope Borough documentation indicates a powerplant efficiency of 14.56 kWh/gal, which is very
good.
Point Hope powerplant diesel generators and bays
Genset Rated
Capacity
Model Emissions Hours*Fuel Injection Min
Load
6 665 kW Caterpillar 3512 Tier 2/3 <3,000 Mechanical 533 kW
7 665 kW Caterpillar 3512 Tier 2/3 <3,000 Mechanical 533 kW
8 910 kW Caterpillar 3512 Tier 2/3 <3,000 Mechanical 533 kW
9 1,050 kW Caterpillar 3512 Tier 3 New Electronic 533 kW
*Since most recent rebuild
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Switchgear
Point Hope has new switchgear using Allen Bradley PLC Device Net which interfaces devices via RS485
and 10/100 Ethernet. This new equipment was installed in this year’s (2014) power plant upgrade.
Geospatial Perspective of Electrical Load
The school is located adjacent to the power plant and is served directly from a dedicated 480V feeder
from the power plant bus. The water treatment plant is located at the far eastern side of the village and
wastewater treatment plant is located in the southwest corner of the village. All other loads are fairly
evenly distributed with the power plant at the approximate center of the village.
Refer to Appendix D for the Point Hope distribution grid schematic.
Phase Balance of Electrical Load
At the present time, WHPacific Solutions Group does not have phase balance information of the Point
Hope power system. Although the phases are presumed to be in balance, this this will be examined
during the design phase of the project.
Transformers
The main transformers, serving each feeder at the power plant, are conservative. In an emergency,
each is capable of supporting the entire village load during peak winter loads. The distribution
transformers are also believed to be liberally-sized for demand with capacity to be loaded to 150% of
rated load during colder winter temperatures. This is based on experience with facility loads in general;
there is no recorded data to confirm this.
Phase and/or Transformer Capacity Location(s) for Additional Load
Although the Point Hope distribution system has significant reserve capacity and redundancy in its
present configuration to support adding wind power generation to the grid, power lines are gradually
being upgraded from #2 ACSR to 1/0 AAAC to increase conductor strength for snow and ice loading and
to prevent problems related to electrolysis corrosion in the Point Hope’s salt air environment. As an
additional benefit, the line upgrade will increase the electrical load capacity of the system, reduce line
loss, and lessen voltage drop through the system.
Note that at the 12.47 kV transmission voltage in Point Hope, 1 MW of distributed three-phase wind
turbine capacity at Site B will add only 46 amps to the 220 amp capacity of the new 1/0 AAAC line, which
with only the airport and tank farm load is (or will be) significantly under-utilized.
Condition of Distribution Lines, Transformers, Poles
North Slope Borough villages generally have some of the better maintained power systems in rural
Alaska. The original power poles in Point Hope have largely been replaced with new, most of the
secondary conductor has been replaced in the past five years, and distribution transformers are being
replaced with larger transformers to meet increasing residential demand. As discussed in the preceding
section, primary conductor is gradually being replaced and upgraded with larger all-aluminum alloy
conductor to improve strength in wind and ice loading and prevent degradation due to electrolysis, a
problem which has plagued ACSR conductor in coastal villages.
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Parasitic and Other Losses
As documented in the 2013 PCE Report, distribution line loss in Point Hope for fiscal year 2013 was
13.0% and powerhouse consumption was 5.9%, yielding a remarkably low 81.1% ratio of sold vs.
generated energy. This indicates a potential problem with the electrical distribution system itself and/or
possibly with billing and recordkeeping. This issue will be investigated during the design phase of the
project and addressed as an integral component of the wind-diesel system design and operations plan.
Wind Turbine Options
Turbine choice was oriented toward turbines that are large enough to match well with Point Hope’s
electrical load. Turbines that meet these criteria are generally in the 100 to 750 kW size range. The
wind power industry, however, does not provide many options as village wind power is a small market
worldwide compared to utility grid-connected projects where wind turbines are 1,000 kW and larger
capacity, or home and farm applications where wind turbines are generally 10 kW or less capacity. For
this project, five wind turbines are considered:
1. Aeronautica AW/Siva 250: 250 kW rated output; new
2. EWT DW 54-900: 900 kW rated output; new
3. Northern Power Systems 360-39-30: 360 kW rated output; new
4. Vestas V39: 500 kW rated output; remanufactured
The choice of selecting new or remanufactured wind turbines is an important consideration and one
which North Slope Borough is carefully considering at present through a separately-contracted
evaluation effort which included visits to the offices and factories of Aeronautica Windpower in
Massachusetts, Northern Power Systems in Vermont, and Halus Power Systems in California (re-
manufacturer of Vestas wind turbines). There are advantages and potential disadvantages of each
turbine, including cost, support and parts availability. Note however that the five wind turbines
presented in this report have solid track records and good support capacity within Alaska. The turbine
evaluation report will be forwarded separately from this conceptual design report.
Aeronautica AW/Siva 250
Aeronautica Windpower, with offices in Plymouth, Massachusetts and production facilities in
Portsmouth, New Hampshire, manufactures the AW/Siva 250 wind turbine in two rotor configurations:
29 meters for IEC wind class design IIA sites and 30 meters for IEC wind class IIIA sites. This turbine is a
Siva (Germany) licensed design. For Point Hope, the 30 meter version likely would be most optimal.
This turbine has a 30 meter rotor diameter, is rated at 250 kW power output, is stall regulated, has a
gearbox-type drive system, and is equipped with asynchronous (induction type) dual-wound (50 kW and
250 kW) generators. Braking is accomplished by passive and hydraulically-actuated pivotable blade tips
and hydraulic disc brakes. The turbine has active yaw control and is available with 30, 40, 45, and 50
meter tubular steel towers.
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AW/Siva 250 specifications:
EWT DW 54-900
The DW 52/54-900 is a direct-drive, pitch-regulated wind turbine with a synchronous generator and
inverter-conditioned power output. More information regarding the EWT DW 52/54-900 wind turbine is
attached and available on EWT’s website: http://www.ewtdirectwind.com/. The turbine boasts a track
record of over 400 operating turbines in many different wind climates. At present, six DW 900 turbines
have been installed in Alaska: two each in Delta Junction, Kotzebue and Nome. For Point Hope, the 54
meter rotor version likely would be most optimal.
Type DW 54 / DW 52
Rotor diameter 54.0 m / 51.5 m
Variable Rotor Speed 12 to 28 rpm
Nominal Power Output 900 kW
Cut-in wind speed 2.5 m/s
Rated wind speed 13 m/s
Cut-out wind speed (10 minute average)25 m/s
Survival wind speed 59.5 m/s
Power output control Pitch controlled variable speed
Type Certificate
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IEC 61400 wind class IIIA (DW 54)
IEC 61400 wind class IIA (DW 52)
Drive System
Generator Synchronous air-cooled EWT-design, multi-pole, wound-rotor.
Power converter Full-power, IGBT-controlled AC-DC-AC ‘back-to-back’ type.
Control System
Bachman PLC control system.
Possibility for remote access via TCP / IP internet and the DMS 2.0 * SCADA system.
Tower
Type Conical tubular steel, internal ascent.
Hub heights 40, 50 and 75 meters.
Safety systems
Main brake action Individual rotor blade pitch (three independent brakes).
Fail-safe brake Individual rotor blade pitch by three independent battery-powered back-up units.
Northern Power Systems 360-39 (NPS 360-39)
At 360 kilowatts of rated power, the new-to-the-market Northern Power 360-39 is an innovative wind
turbine with gearless direct drive design, permanent magnet generator, and pleasing aesthetics. The
turbine will be marketed in two versions: the NPS 360 for temperature climates and the NPS 360 Arctic
for cold climates such as Alaska. Differences between the two include heaters and insulation for the
Arctic version, plus certification that metal used in the tower and nacelle frame are appropriate for
operation to -40° C (-40° F). Note that design characteristics of the NPS 360-39 will be very similar to the
NPS 100 B model turbine which is well represented in Alaska.
According to Northern Power Systems, the proprietary permanent magnet generator is central to the
design of the NPS 100 (and the new NPS 360) drivetrain. Permanent magnet generators offer high
efficiency energy conversion, particularly at partial load, and require no separate field excitation system.
Permanent magnet generators are lighter, more efficient, and require less assembly labor than
competing designs. The Northern Power permanent magnet generator was designed in conjunction with
its power converter to create an optimized solution tailored for high energy capture and low operating
costs.
A key element of Northern Power’s direct drive wind turbine design is the power converter used to
connect the permanent magnet generator output to the local power system. Northern Power designs
and manufactures power converters for its wind turbines in-house, with complete hardware, control
design, and software capabilities. In 2006, the American Wind Energy Association (AWEA) awarded its
annual Technical Achievement Award to Northern Power’s Chief Engineer, Jeff Petter. It recognized his
expertise and leadership in the development of Northern Power Systems’ FlexPhase™ power converter
for mega-watt scale wind turbine applications. The FlexPhase power converter combines a unique,
patent-pending circuit design with a high bandwidth control system to provide unique generator
management, power quality, and grid support features. The FlexPhase converter platform offers a
modular approach with a very small footprint and 20-year design life.
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NPS 360-39 Class IIIA general information
Model NPS 360-39
Design Class IEC 61400-1, 3rd ed., WTGS IIIA
Power Regulation Variable speed, pitch control
Orientation Upwind
Yaw Control Active
Number of Blades Three
Rotor Diameter 39 meters
Rated Electrical Power 360 kW
Cut-in/Cut-out Wind Speeds 3 m/sec; 25 m/sec
Controller Type PLC (programmable logic controller)
Hub Height; tower type 30 meters; 3-section tubular steel monopole
Vestas V39
Halus Power Systems of San Leandro, California remanufactures the legacy suite of Vestas wind
turbines, rated from 65 kW (the V15) to 600 kW (the V44). Of most interest to North Slope Borough for
Point Hope is the V39 turbine. The V39 is a 39 meter rotor diameter, 500 kW rated output, pitch-
controlled, gearbox-type drive system, asynchronous double-wound generator wind turbine originally
built by Vestas A/S in Denmark. The turbine has active yaw control and is available with a 40 meter steel
tower as standard and higher towers by special fabrication. Although the smaller Vestas V27 nacelle,
tower, and blades can be shipped in standard shipping containers, eliminating the expense and risk of
damage with break bulk shipping, V39 blades would require more costly break bulk shipping.
Braking and stopping are accomplished by full feathering of the rotor blades, which is a desirable feature
of pitch-controlled wind turbines. An emergency stop activates the hydraulic disk brake, which is fitted
to the high speed shaft of the gearbox. All functions of the turbine are monitored and controlled by the
microprocessor-based control unit. Blade position (pitch angle) is performed by the hydraulic system,
which also delivers hydraulic pressure to the brake system. Both are fail-safe in the sense that loss of
hydraulic pressure results in feathering of the rotor blades and activation of the disk brake. Of interest
with respect to the pitch system is the mechanical interlink of the three rotor blades contained in the
hub nose cone. With this simple but ingenious design, it is not possible for the turbine blades to pitch
differently from each other.
A smaller version of the V39, the V27, was Vestas’ workhorse turbine for many years and thousands
were installed worldwide. Design of the turbine pre-dates the IEC 61400-1 standards, but by present
criteria the turbine can be considered Class II-A and possibly even Class I-A. The V27 is well regarded as
a rugged, tough turbine with an outstanding operational history. Four V27 wind turbines are
operational in Alaska: three on Saint Paul Island and one at the Air Force’s Tin City Long Range Radar
Site. Additionally, two V39 wind turbines were installed by TDX Power in Sand Point, Alaska and are
operational. Because of the large numbers of Vestas turbines (legacy and new) deployed in North
America, Vestas continues to maintain multiple facilities in the United States including a large
manufacturing facility in Colorado and an office in Portland, Oregon. Vestas can provide technical
support and spare parts for their legacy turbines (from V17 through V44) as needed. In addition, due to
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the large number of deployed turbines in North America and worldwide, spare parts are widely available
from many suppliers.
Wind-Diesel HOMER Model
Considering North Slope Borough’s goal of displacing as much diesel fuel for electrical generation as
possible and yet recognizing the present limitations of high penetration wind power in Alaska and North
Slope Borough’s desire to operate a highly stable and reliable electrical utility in Point Hope, only the
medium penetration wind-diesel configuration scenario was modeled with HOMER software. Note that
low penetration wind was not modeled as this would involve use of smaller farm-scale turbines that are
not designed for severe cold climates, and low penetration would not meet North Slope Borough’s goal
of significantly displacing fuel usage in Point Hope.
As previously noted, a medium penetration wind-diesel configuration is a compromise between the
simplicity of a low penetration wind power and the significant complexity and sophistication of the high
penetration wind. With medium penetration, instantaneous wind input is sufficiently high (at 100 plus
percent of the village electrical load) to require a secondary or diversion load to absorb excess wind
power, or alternatively, to require curtailment of wind turbine output during periods of high wind/low
electric loads. For Point Hope, appropriate wind turbines for medium wind penetration are generally in
the 100 to 300 kW range with more numbers of turbines required for lower output machines compared
to larger output models.
There are a number of comparative medium penetration village wind-diesel power systems presently in
operation in Alaska. These include the AVEC villages of Toksook Bay, Chevak, Savoonga, Kasigluk,
Hooper Bay, among others. All are characterized by wind turbines directly connected to the AC
distribution system. AC bus frequency control during periods of high wind penetration, when diesel
governor control would be insufficient, is managed by the sub-cycle, high resolution, and fast-switching
capability of the secondary load controller (SLC). Ideally, the SLC is connected to an electric boiler
serving a thermal load as this will enhance overall system efficiency by augmenting the operation of the
fuel oil boiler(s) serving the thermal load.
Powerplant
Point Hope is equipped with four Caterpillar 3512 diesel generators. Note that these generators are
modeled at 15 percent minimum load, but recent correspondence with North Slope Borough
powerplant personnel indicates that all four generators are operated at a minimum 533 kW load. This
would equate to 80% minimum load for generators 6 and 7, 58% for generator 8, and 51% for generator
9. This discrepancy will be examined in detail during the design phase of the project.
Diesel generator HOMER modeling information
Diesel generator Cat 3512
(bays 6 and 7)
Cat 3512
(bay 8)
Cat 3512
(bay 9)
Power output (kW)665 910 1,050
Intercept coeff. (L/hr/kW rated)0.0194 0.0194 0.0194
Slope (L/hr/kW output) 0.2325 0.2325 0.2325
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Diesel generator Cat 3512
(bays 6 and 7)
Cat 3512
(bay 8)
Cat 3512
(bay 9)
Minimum electric load (%)15.0%
(100 kW)
15.0%
(135 kW)
15%
157 kW)
Heat recovery ratio (% of generator waste
heat energy available to serve the thermal
load; when modeled)
35 35 35
Notes: Intercept coefficient – the no-load fuel consumption of the generator divided by its capacity
Slope – the marginal fuel consumption of the generator
Caterpillar 3512 Fuel Efficiency
The Caterpillar 3512 is the primary diesel generator type in the Point Hope power plant. The graphs
below, obtained from NC Machinery, illustrates fuel usage and heat production of the Cat 3512 diesel
engine. Fuel usage information in the Homer model (as presented in the preceding table) differs slightly
in that AEA testing information obtained from Mr. David Lockard was used.
Cat 3512 Fuel Efficiency
Cat 3512 Heat Production
Cat 3512 Electrical and Thermal Efficiency
Electrical and thermal efficiency of the Cat 3512 diesel engine is shown below. Note that North Slope
Borough did not report a seasonal or other specific scheduling plan, hence Homer software was
programmed to select the most efficient diesel for any time period. Also note that Homer was
programmed to allow parallel diesel generator operation, which is verfied on review of North Slope
Borough’s Point Hope power plant logs.
y = 0.00001049x2 + 0.051512x + 4.4482
R2 = 0.99999
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
50.0
0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750
Output - kW
Fuel Use
y = 0.001934x + 0.08595
R2 = 0.9984
0.000
0.200
0.400
0.600
0.800
1.000
1.200
1.400
1.600
0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750
Output - kW
Available Jacket Water Heating
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Cat 3512 electrical and thermal
efficiency curves
Cat 3512 Recovered Heat Ratio
The 35 percent heat recovery potential of the Cat 3512 generator was derived from technical data
supplied by NC Power Systems. Homer software defines the heat recovery ratio as the percentage of
generator waste heat energy available to serve the thermal load. Generator waste heat is energy not
used for work; work being the energy output of the generator. As the table below indicates, the
recovered heat ratio of the Cat 3512 generator equipped with an aftercooler (known also as an
intercooler), is 41.8%. Assuming 15% system heat loss, actual heat recovery ratio is 35.5%, which was
modeled at 35%.
Cat 3512 heat recovery table
Wind Turbines
Wind turbine options for Point Hope are discussed previously in this report. For Homer modeling,
standard temperature and pressure (STP) power curves were used. This is quite conservative in that
actual wind turbine power production in Point Hope will typically be higher than predicted by the STP
power curves due to the cold temperature climate and consequent high air density of the area.
electricity
gen pwr % load
rej to JW
(BTU/m)
rej to
atmos
(BTU/m)
rej to
exhaust
(BTU/m)
exh rcov to
350F
(BTU/m)
from oil
cooler
(BTU/m)
from after
cooler
(BTU/m)
work
energy
(BTU/m)
TOTAL
(BTU/m)
665 100 23,146 5,857 33,610 15,753 4,896 3,037 39,865 102,478
22.6% 5.7% 32.8% 15.4% 4.8% 3.0% 38.9% 100.0%
37.0% 9.4% 53.7% 25.2% 7.8% 4.9%
37.0% 4.9% 41.8%
Recovered heat ratio, Homer, 15% heat loss assumed 35.5%
% total energy
rejected energy returned energy to JW
% of remaining non-
work energy
JW and aftercooler
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Aeronautica AW/Siva 250 power curve EWT DW 54-900 power curve
Northern NPS 360-39 power curve Vestas V39 power curve
Electric Load
For modeling purposes with Homer software, the Point Hope electric load was derived from calendar
year 2013 powerplant data forwarded to V3 Energy, LLC by North Slope Borough in an Excel spreadsheet
entitled 2013_Point_Hope_PPOR. The spreadsheet tabulates power output log readings hand-collected
(by the powerplant operators) hour for each diesel engine on-line. If two diesel engines are operating in
parallel, individual generator power output is summed to equal total hour (average) load. For each day,
generator output is summed to yield kWh produced per generator and aggregate. Below are the
monthly Point Hope load profile for 2013, an example of daily generator output/load data, and electrical
profile data used in Homer software for the system analysis.
Point Hope 2013 energy demand graph
0
100
200
300
400
500
600
700
1 2 3 4 5 6 7 8 9 10 11 12Electric Load (MWh)Month
Point Hope Powerplant, 2013
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Point Hope powerplant log data, sample day
For Homer input, load data is organized into 8,760 lines, representing 24 hours per day, 365 days per
year. In a number of instances diesel generator power (load) data was missing from the data set. In
these cases, missing data was interpolated with reference to data before and after the blank sections.
The graphs below show a summary of the Point Hope electric load from the referenced powerplant
Excel spreadsheet.
Engine 6
Caterpillar 3512
Serial # 67Z1167
Engine 7
Caterpillar 3512
Serial # 67Z1266
Engine 8
Caterpillar 3512
Serial # 67Z1165
Total Load Total Load Total Load
0:00 380.00 437.00 817.00 955.00
1:00 412.00 504.00 916.00
2:00 402.00 484.00 886.00
3:00 413.00 478.00 891.00
4:00 475.00 476.00 951.00
5:00 427.00 494.00 921.00
6:00 440.00 515.00 955.00
7:00 261.00 318.00 317.00 896.00
8:00 452.00 431.00 883.00
9:00 459.00 442.00 901.00
10:00 447.00 446.00 893.00
11:00 427.00 410.00 837.00
12:00 409.00 399.00 808.00
13:00 424.00 414.00 838.00
14:00 444.00 410.00 854.00
15:00 436.00 418.00 854.00
16:00 427.00 409.00 836.00
17:00 417.00 391.00 808.00
18:00 389.00 364.00 753.00
19:00 371.00 346.00 717.00
20:00 369.00 347.00 716.00
21:00 374.00 352.00 726.00
22:00 394.00 360.00 754.00
23:00 380.00 350.00 730.00
Total 2735 8421 8985 20,141.00
Point Hope Power Plant
March 6, 2013
Hour Total Hourly
Total Load
Peak Load of the
Day
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Point Hope electric load
Thermal Load
The Point Hope powerplant is equipped with a heat recovery system to extract jacket water waste heat
from the diesel generators and supply it to the following village thermal (heat) loads: powerplant,
school, utilidor, grey water plant, health clinic, and old water plant/washeteria. Possible additional
connection points are the PSO, fire station, USDW, and the sewage treatment plant according to a
February, 2010 draft RSA Engineering, Inc. report to North Slope Borough entitled North Slope Borough
Village Heat Recovery Project Analysis Report, CIP No. 13-222. Per the RSA report, the combined design
day heat load of the above-referenced structures is 4.03 MMBTU/hr. The additional thermal loads, if
connected, would increase the design data heat load by 3.60 MMBTU/hr. Data from the RSA Engineering
report details monthly existing waste heat (from the powerplant heat recovery system) consumption
and the estimated contribution of waste heat to the actual heat load. Additional data from RSA
Engineering is documented in the table below.
RSA Engineering thermal load data, existing heat loads
month
avg power
(kW)
available
waste heat
(BTU/hr)
available
heat
(MMBTU)
available
waste heat
(kWh)
hourly heat
available
(kW)
waste heat
consumed
(BTU/hr)
waste heat
consumed
(kW)
1 762 2,080,440 1,498 438,996 610 2,080,440 610
2 660 1,802,429 1,298 380,333 528 1,802,429 528
3 602 1,644,099 1,184 346,923 482 1,644,099 482
4 708 1,933,398 1,392 407,969 567 1,933,398 567
5 495 1,353,368 974 285,576 397 1,353,368 397
6 737 2,013,287 1,450 424,826 590 1,065,766 312
7 532 1,453,883 1,047 306,786 426 747,920 219
8 456 1,246,681 898 263,064 365 713,918 209
9 481 1,313,466 946 277,156 385 1,511,897 443
10 629 1,719,074 1,238 362,744 504 1,479,005 433
11 523 1,429,910 1,030 301,727 419 1,429,910 419
12 709 1,937,326 1,395 408,797 568 1,937,326 568
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Data from the above table and additional information obtained from RSA Engineering, Inc. for the village
of Kaktovik was converted to kW (heat) load and scaled by a factor of 1.22 as adjustment for the higher
thermal loads in Point Hope. Data was uploaded to Homer software to create a thermal load profile for
modeling purposes. Diurnal thermal load variation is not contained in the RSA report and is unknown,
hence modeled as constant.
Point Hope thermal load
Wind Turbine Configuration Options
Discussions between WHPacific Solutions Group, V3 Energy, LLC and North Slope Borough to date have
indicated that the borough’s goals with a wind-diesel system in Point Hope is to offset a significant
percentage of fuel used in the powerplant, but not create a highly complex system with significant
thermal offset and/or electrical storage capability. This philosophy dictates a medium penetration
design approach (see previous section of this report) where wind power supplies a reasonably high
percentage of the electric load, but diesel generation remains on-line to provide spinning reserve.
Medium penetration design, though, means that instantaneous wind power will at times be well over
100 percent of the load. This can result in unstable grid frequency, which occurs when electrical power
generated exceeds load demand. In a wind-diesel power system without electrical storage, there are
three options to prevent this possibility:
1. Curtail one or more wind turbines to prevent instantaneous wind penetration from exceeding 100
percent (one must also account for minimum loading of the diesel generator).
2. Install a secondary load controller with a resistive heater. The secondary load controller is a fast-
acting switch mechanism commanding heating elements to turn on and off to order to maintain
stable frequency. The resistive heating elements can comprise a device as simple as a heater
ejecting energy to the atmosphere or an interior air space, or more desirably, an electric boiler
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serving one or more thermal loads. The boiler can be installed in the powerplant heat recovery loop
and operate in parallel with fuel oil boilers.
3. Equip the wind turbines with output controllers (some wind turbines, such as the EWT DW 900 and
the NPS 360, are pre-equipped with these controllers) to enable reduction of turbine power to
match load demand. This is a more efficient turbine control strategy than curtailment, but of course
presents an additional cost to the project and “wastes” wind energy in the sense that one is
purposely throttling the turbine(s).
For medium penetration design, frequency control features as described above are necessary because,
generally speaking, diesel generators paralleled with wind turbines during periods of high wind energy
input may not have sufficient inertia to control frequency by themselves. This design philosophy is true
of most wind-diesel systems presently operational in Alaska and provides a solid compromise between
the minimal benefit of low penetration systems and the high cost and complexity of high penetration
systems.
Many utilities prefer to install more than one wind turbine for a village wind power project to provide
redundancy and continued renewable energy generation should one turbine be out-of-service for
maintenance, fault, or other reasons. This guidance is modified for Point Hope in that a single single
EWT DW 54-900 turbine configuration is included with the multi-turbine configuration options.
Referencing the medium wind power penetration design philosophy discussed above, modeled wind
turbine configuration options considered in this report are as follows:
Aeronautica AW 250, four turbines (1,000 kW capacity)
EWT DW 52-900, one turbine (900 kW capacity)
Northern Power NPS 360-39, three turbines (1,080 kW capacity)
Vestas V39, two turbines (1,000 kW capacity)
Turbine types are not mixed, however, as it is assumed that North Slope Borough will select only one
type of wind turbine. A typical configuration for this project is show below.
Sample Wind-diesel configuration for Point Hope
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System Modeling and Technical 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 philosophy: turbines are connected
to the electrical distribution system to serve the electrical load and a secondary load controller and an
electric heater or boiler to divert excess electrical power to offset thermal load(s) via a secondary load
controller.
HOMER energy modeling software was used to analyze the Point Hope power generation system.
HOMER 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. The following wind-diesel system
configurations were modeled for this conceptual design report. A one-line diagram of this proposed
system is presented in Appendix E.
Modeled wind-diesel configurations
Turbine
No.
Turbines
Installed
kW Tower Type
Hub Height
(meters)
Aeronautica
AW/Siva 250 4 1,000 Monopole 30
EWT DW 52-900 1 900 Monopole 35
Northern Power
NPS 360-39 3 1,080 Monopole 30
Vestas V39 2 1,000 Monopole 40
Modeling assumes that wind turbines constructed in Point Hope will operate in parallel with the diesel
generators. Excess energy presumably will serve thermal loads via a secondary load controller and
electric boiler that will augment the existing jacket water heat recovery system and is modeled as such
in the technical analysis of this report (although not in the economic analysis).
Although not considered in this report, deferrable electric and/or remote node thermal loads could be
served with excess system energy. This possibility be considered during the design phase of this project.
Technical modeling assumptions
Operating Reserves
Load in current time step 10%
Wind power output 50% (diesels always on)
Fuel Properties (no. 2 diesel for
powerplant)
Heating value 46.8 MJ/kg (140,000 BTU/gal)
Density 830 kg/m3 (6.93 lb./gal)
Fuel Properties (no. 1 diesel to serve
thermal loads)
Heating value 44.8 MJ/kg (134,000 BTU/gal)
Density 830 kg/m3 (6.93 lb./gal)
Diesel Generators
Efficiency 14.6 kWh/gal (North Slope Borough data)
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Minimum load 15%
Schedule Optimized
Wind Turbines
Net capacity factor 85% (adjusted by reducing mean wind speed in Homer
software)
Turbine hub height As noted
Wind speed 7.12 m/s at 30 m level at met tower site; wind speed scaled
to 6.51 m/s for 85% turbine net AEP
Density adjustment Density not adjusted
Energy Loads
Electric 18,581 kWh/day mean annual electrical load
Thermal 14,797 kWh/day mean annual via recovered heat loop
Fuel oil boiler efficiency 85%
Electric boiler efficiency 100%
Model Results
The Site B wind resource is presumed to be identical to that measured at the met tower site. Given the
flat, featureless terrain between the met tower and Site B, this is a reasonable assumption. Site B may
be height restricted, however, hence lowest possible turbine hub heights possible are modeled and
recommended. Given the Point Hope’s very strong wind resource and moderate wind shear, low hub
heights are acceptable and may be desirable from an aesthetic point of view to reduce visual impact of
the project. Note that turbine energy production is modeled at 85 percent net.
AW/Siva 250, four (4) turbines, 30 m hub height
This configuration models one AW/Siva 250 kW wind turbine at Point Hope Site B at a 30 meter hub
height and generating 85 percent of maximum annual energy production.
Energy table, four AW/Siva 250’s, 85% net AEP
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Chart, four AW/Siva 250’s
EWT DW 54-900, one (1) turbine, 35 m hub height
This configuration models one EWT DW 54-900 wind turbine at Point Hope Site B at a 35 meter hub
height and generating 85 percent of maximum annual energy production.
Energy table, one DW 54-900, 85% net AEP
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Chart, one DW 54-900
Northern Power NPS 360-39, three (3) turbines, 30 m hub height
This configuration models three Northern Power Systems NPS 360-39 wind turbines at Point Hope Site B
at a 30 meter hub height and generating 85 percent of maximum annual energy production.
Energy table, three NPS 360-39’s, 85% net AEP
-
100
200
300
400
500
600
700
1 2 3 4 5 6 7 8 9 10 11 12
Electric Load Turbine Energy Excess Energy to Thermal
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Chart, three NPS 360-39’s
Vestas V39, two (2) turbines, 40 m hub height
This configuration models two Vestas V39 wind turbines at Point Hope Site B at a 40 meter hub height
and generating 85 percent of maximum annual energy production.
Energy table, two V39’s, 85% net AEP
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Chart, two V39’s
Economic Analysis
Modeling assumptions are detailed in the table below. Many assumptions, such as project life, discount
rate, operations and maintenance (O&M) costs, etc. are AEA default values. 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 Point Hope powerplant with its present
configuration of diesel generators and the existing thermal loads connected to the heat recovery loop.
Fuel Cost
A fuel price of $5.44/gallon ($1.44/Liter) was chosen for the 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, 2103 and the 2013_06_R7Prototype_final_07012013 Excel
spreadsheet, also written by ISER. The $5.44/gallon price reflects the average value of all fuel prices
between the 2015 (the assumed project start year) fuel price of $4.63/gallon and the 2034 (20 year
project end year) fuel price of $6.41/gallon using the medium price projection analysis with an average
CO2-equivalent allowance cost of $0.57/gallon included.
By comparison, the fuel price for Point Hope reported to Regulatory Commission of Alaska for the 2012
PCE report is $4.30/gallon ($1.14/Liter), without inclusion of the CO2-equivalent allowance cost.
Assuming a CO2-equivalent allowance cost of $0.40/gallon (ISER Prototype spreadsheet, 2013 value), the
2012 Point Hope fuel price was $4.70/gallon ($1.24/Liter).
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Heating fuel displacement by excess energy diverted to thermal loads is valued at $6.49/gallon
($1.72/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 CO2-equivalent allowance cost) plus $1.05/gallon, assuming heating oil displacement
between 1,000 and 25,000 gallons per year.
Fuel cost table, CO2-equivalent allowance cost included
ISER med. projection 2015 (/gal) 2034 (/gal)
Average
(/gallon)
Average
(/Liter)
Diesel Fuel $4.63 $6.41
$5.44 $1.44
Heating Oil $5.68 $7.46 $6.49 $1.72
Wind Turbine Project Costs
Construction cost for wind turbine installation and integration with the diesel power plant will be
accurately estimated during the design phase of the project. Project costs are estimated in this
conceptual design report in order to provide comparative valuation. The client is strongly encouraged
not to select the wind turbine configuration option based on cost alone, especially with the highly
tentative costs presented in this conceptual design report, as other factors may be more important from
an operational, maintenance, integration, and support point of view.
Economic modeling assumptions
Economic Assumptions
Project life 20 years (2015 to 2034)
Discount rate for NPV 3% (ISER spreadsheet assumption)
System fixed capital cost (plant
upgrades required to accommodate
wind turbines)
Included in turbine project cost
Fuel Properties (no. 2 diesel for
powerplant)
Price (20 year average; ISER 2013,
medium projection plus social cost of
carbon)
$5.44/gal ($1.44/Liter)
Fuel Properties (no. 1 diesel to serve
thermal loads)
Price (20 year average; ISER 2013,
medium projection plus social cost of
carbon)
$6.49/gal ($1.72/Liter)
Diesel Generators
Generator capital cost $0 (already installed)
O&M cost $0.02/kWh (ISER spreadsheet assumption)
Efficiency 14.6 kWh/gal (North Slope Borough data)
Wind Turbines
Net capacity factor 85% (adjusted by reducing mean wind speed in Homer
software)
O&M cost $0.049/kWh (ISER spreadsheet assumption)
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Wind Turbine Costs
Modeling Results
The reader is cautioned to note that the economic benefit-to-cost ratios calculated by the ISER method
do not account for heat loss from the diesel engines due to reduced loading and subsequent impact on
heating fuel usage to serve the thermal loads. ISER cost modeling assumptions are noted above or are
discussed in the 2013_06_R7Prototype_final_07012013 Excel spreadsheet. Net annual energy
production of the wind turbines was assumed at 85 percent to reflect production losses due to
operations and maintenance down time, icing loss, wake loss, hysteresis, etc.
Economic comparison table of Point Hope wind turbine options
Data Analysis Uncertainty
There are a number of concern and potential problems with data used for modeling in this report.
Primary among them is that Point Hope powerplant data are manually-collected log readings, not
computer-calculated average power per hour as one might conclude by reviewing North Slope
Borough’s 2013_Point_Hope_PPOR file. While manually-collected logs may be desirable from an
Operations perspective, manual logs are not suitable for modeling as they represent only a brief
“snapshot” of the load at that moment and are generally unrepresentative, sometimes dramatically so,
of actual average load demand during the time period represented by the log entry.
Note that the manually-collected logs also likely account for the odd occurrences of very low electrical
loads for a particular hour that are bracketed by much higher loads on either side. In reality this load
variation most likely did not occur, but identifying and correcting every questionable occurrence in an
8,760 line data set is extremely tedious and was not considered necessary for this analysis.
The thermal load appears to be reasonably well documented, but the data is four years old.
Additionally, the RSA Engineering report was structured such that actual load demand is not readily
apparent. This will be a consideration during design should North Slope Borough wish to consider much
higher wind penetrations where thermal offset would be considerably larger than modeled.
Config-
uration
No.
Turbs Turbine Freight Install Civil
Distribu-
tion
Power-
plant
Project
Cost Cost/kW
AW 250 4 1,000 2.40 0.70 2.10 2.40 0.40 0.50 8.50 8,500$
EWT 900 1 900 1.75 0.70 1.80 1.80 0.40 0.50 6.95 7,700$
NPS 360 3 1,080 2.20 0.70 2.00 2.20 0.40 0.50 8.00 7,400$
V39 2 1,000 1.08 0.70 1.90 2.00 0.40 0.50 6.58 6,600$
Wind
Capacity
(kW)
Estimated Cost (in $millions)
Config-
uration
Project
Cost
NPV
Benefits
NPV
Costs
B/C
ratio
AW 250 1,000 8.50 10.05 7.55 1.33 143,700 4,700 148,400
EWT 900 900 6.95 10.16 6.17 1.65 145,000 5,000 150,000
NPS 360 1,080 8.00 12.53 7.11 1.76 170,600 12,500 183,100
V39 1,000 6.58 10.49 5.85 1.79 147,300 7,000 154,300
Diesel
Fuel
Saved
(gal/yr)
Heat Oil
Saved
(gal/yr)
Petroleum
Fuel
Saved
(gal/yr)
(in $ millions)
Wind
Turbine
Capacity
(kW)
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Project costs are estimated in this conceptual design report and will be determined with greater
accuracy during the design phase of the project.
Discussion
For this conceptual design report, only proven and robust wind turbines were considered for evaluation,
hence any of the configurations considered can be designed and operated to meet expectations of high
performance and reliability. Integration requirements will vary depending on the type of electrical
generator in the turbine (synchronous vs. asynchronous), inverter-conditioning, soft-start or other
similar grid stability control features, VAR support if necessary, minimum loading levels of the diesel
generators as a percentage of the electric load, secondary load controller resolution and response time,
among others. These design elements are beyond the scope of this conceptual design project, but the
technology has matured such that one may be assured that wind turbines are controllable when
operating in Point Hope in a medium penetration/non-storage mode.
With these issues in mind, the primary deciding factors for selection of wind turbine(s) for Point Hope
will be cost, reliability, aesthetics, redundancy, support, and commonality.
Cost
Note that the cost estimates in this report were not produced with the same level of precision and
accuracy as will occur during the design phase and so should be treated with a substantial level of
caution. Also note that many cost parameters such as operations and maintenance costs over the life of
the project are estimated using Alaska Energy Authority default values and may not be realistic for any
particular turbine configuration option. For this reason the benefit-to-cost ratios indicated in the
preceding table should not be ranked nor compared. The point of including the table is to indicate that
per the parameters of this analysis, all four turbine options exhibit beneficial economic potential for
North Slope Borough and the community of Point Hope.
Reliability
Turbine reliability can be obtained from manufacturer data, third party reviews, and utility experience.
Even with a great warranty and promises of strong manufacturer support, robust and reliable wind
turbines are highly desirable. Point Hope is an isolated community and expensive to visit, so it is
desirable to install equipment where the likelihood of nagging maintenance issues are minimal. All
warranty and maintenance support periods eventually end, and North Slope Borough will want to be
assured that the turbines they purchase will serve them well in the future.
Aesthetics
This is a highly subjective consideration that undoubtedly will elicit a number of strong and conflicting
opinions. Ultimately, Point Hope residents must collectively agree on the aesthetic impact of wind
turbines in their community. Simply put, wind turbines will have a visual impact in Point Hope and will
easily be the highest and most dominating structure(s) for miles around. Which is preferable: one large,
very high turbine or two or more smaller, clustered turbines? This is a difficult question for most people
to answer in the abstract because one must mentally imagine wind turbines at Site B (or the other sites)
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where at present the landscape is flat, bare and nearly featureless. Software modeling that
superimposes virtual wind turbine(s) onto the Google Earth image of Point Hope may prove beneficial
for the discussion.
Redundancy
A single wind turbine would be redundant in the sense that diesel generation will continue to function
to meet electrical load demand should the turbine be off-line for maintenance or a fault condition. On
the other hand, a single wind turbine is not redundant with respect to wind generation itself. Should a
single installation wind turbine be out of service for an extended period of time, wind energy would not
be generated during the outage.
Support
Manufacturer warranty and support will be a primary consideration of North Slope Borough given its
responsibility as electrical utility for Point Hope. The Borough must have confidence that the turbine
manufacturer and/or its representatives will be available throughout the life of the project. This is a
matter of trust and ultimately a value that North Slope Borough must determine for itself.
Commonality
This is a practical consideration for North Slope Borough. There are four Borough village wind projects
presently entering the design phase: Point Hope, Point Lay, Wainwright, and Kaktovik. In the related
Kaktovik project, North Slope Borough arranged a manufacturer site visit report in March 2014 to Halus
Power Systems in California (remanufacturer of Vestas turbines), Aeronautica Windpower in
Massachusetts, and Northern Power Systems in Vermont. Objectives of this trip were to meet company
representatives, establish relationships, and assess the desirability and potential of each as the “fleet
turbine” provider for the Borough.
There are many desirable aspects of a fleet turbine – whether a single turbine model or a family of
models – that would be attractive to North Slope Borough. These include a single supplier and point of
contact, a common control system for all turbines in the fleet, common parts, and utility and village
technicians that learn to service only one type of turbine, not two or more.
On the other hand, given the variability in electrical load profile and site dimensions and height
constraints, no one turbine manufacturer addressed in this conceptual design report provides the
perfect solution for all four North Slope Borough villages. It may be more optimal cost-wise to install a
turbine(s) from one manufacturer in one or more villages and turbine(s) from a different manufacturer
in the remaining villages.
Turbine Recommendation
A number of factors presented in the discussion section above are the province of North Slope Borough
and/or the community of Point Hope to decide, such as aesthetic considerations and confidence in
manufacturer guarantees and proffered support. These factors and others will influence the turbine
configuration decision for the design phase of the project. Nevertheless and with these issues in mind,
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the configuration of three Northern Power Systems NPS 360-39 wind turbines (with the possibility of
additional turbines in the future) is recommended by WHPacific Solutions Group and V3 Energy as the
preferred option for wind power development in Point Hope.
WHPacific Solutions Group and V3 Energy recommend a configuration of two Vestas V39 wind turbines
as an alternate option, and a configuration of four AW/Siva 250 wind turbines as a second alternate
option, but less is known about the Siva turbine compared to Vestas, hence some hesitancy about this
option at the present time.
These recommendations are based on the following considerations:
Cost – Preliminary cost modeling indicates that the EWT DW 900, NPS 360-39, and V39 options
are relatively equal with respect to life-cycle economic benefit. The AW/Siva 250 option
appears to have a lower life-cycle economic benefit, but still positive.
Reliability – All turbine options presented in this report are considered to be reliable machines
with proper maintenance and support.
Aesthetics – The NPS 360-39 is offered only on a relatively low 28.5 meter tower (for a 30 meter
hub height), minimizing the visual impact of this turbine compared to the others. The alternate
turbines, however, are available on at least 40 meter towers on the low end, so their visual
impact is not much greater.
Redundancy – With respect to redundancy, WHPacific Solutions Group and V3 Energy
recommend two or more wind turbines for Point Hope. Despite the admirably excellent
availability history of the EWT wind turbine in their typical grid-connected installations, it should
be recognized that all wind turbines considered in this conceptual design report have excellent
availability histories when grid-connected.
As a general rule though, wind turbine availability has been lower in Alaska village wind-diesel
systems than in grid-connected applications. There are many reasons for this, principally related
to integration and operational factors. Some of these issues can be mitigated with careful
design and planning, but an expectation of utility-experience wind turbine availability is
unrealistic in rural Alaska. With this reality in mind, installing at least two wind turbines enables
continuity of wind power production should one turbine be out of service for an extended
period of time.
Support – All four turbine manufacturers evaluated in this conceptual design report are highly
regarded companies with extensive depth and capability to provide warranty and continuing
support over time with both factory personnel and Alaska-based representatives. In addition, all
four companies will train North Slope Borough personnel to operate and maintain the turbines.
Commonality – Considering the electric load demand and wind turbine site constraints in Point
Hope, Point Lay, Wainwright and Kaktovik (North Slope Borough’s companion wind power
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project villages), only the Aeronautica, Northern Power Systems, and Vestas family of turbines
can be used in all four communities.
It is the opinion of WHPacific Solutions Group and V3 Energy LLC that North Slope Borough will
find it less demanding to manage one type of wind turbine among several village projects than
two or more turbine types, other factors aside.
Single Turbine Option
The EWT DW 900 is an admirable wind turbine and highly suitable for Point Hope, but recommending it
would counter the values of redundancy and commonality expressed above. Although WHPacific
Solutions Group and V3 Energy believe that North Slope Borough would be better served with
redundant wind turbine capacity in their project communities, this is not strictly necessary for a
successful wind project. It should be noted that EWT offers performance guarantees for their turbines
that mitigates the risk of a single turbine application which North Slope Borough may wish to consider.
Commonality of wind turbines for all four planned wind power projects (Point Hope, Point Lay,
Wainwright, and Kaktovik), however, is considered to be in the Borough’s best interests and hence the
recommendation of a wind turbine that will be suitable for all four communities. Should North Slope
Borough be willing to consider two turbine types, the EWT DW 900 may be the best choice for Point
Hope after all, especially if Site A is chosen as the project location. Given the very constrained nature of
Site A, it can accommodate up to two EWT 900 turbines (this presumes future expansion) but could not
accommodate the equivalent power output capacity (1,800 kW) with the other turbine models
addressed in this report (except for an Aeronautica AW 750, which was not presented, but is an option).
Wind Turbine Layout
Site B boundaries are not defined at present, but given the large Tikigaq land ownership in this site area
and lack of Native Allotment boundaries (except between airport access road and the coast, east side of
Site B area), available land for wind turbine layout is expected to be fairly unrestricted. The image
below shows three Northern Power Systems NPS 360-39 wind turbines (describer later in this report) in
a west-to-east alignment with four rotor diameter (approximately 160 meters) separation. This is within
the three to five rotor diameter separation generally recommended for turbine array design. Precise
turbine locations with attendant wake loss (array efficiency) calculations will be modeled during the
design phase of this project after site and turbine selections.
Refer to Appendix F for drawings of the existing electrical distribution system and necessary expansion
to connect wind turbines located at Site B. As indicated, only approximately 800 ft. (0.15 miles) of new
12.47 kV distribution is required. Should wind turbines be located at Site A, 2.6 miles of new 12.47 kV
distribution would be necessary, a distance seventeen times that for Site B.
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Proposed NPS 360-39 turbine layout, Site B
Data Collection Recommendation
Prior to or at least during the design phase of the Point Hope wind power project, North Slope Borough
is strongly encouraged to implement an enhanced power plant monitoring and data collection effort to
obtain average and transient load and other data not presently available. To capture transient behavior,
highly granular data (one second or less averaging time) is most desirable. Data of this nature is
extremely valuable for the design process and significantly reduces the risk of design errors and/or
omissions resulting from unknown or unrecognized behavior of existing system components.
Project Design Penetration Consideration
This conceptual design report focused on four wind turbine configuration options that achieved
approximately 33 percent wind power penetration. During design, presuming that the turbine type has
been selected, North Slope Borough is encouraged to consider the benefits and cost implications of
additional wind turbine capacity; for instance, 50 percent and higher average wind power penetration.
This evaluation can be achieved with Homer software and other modeling tools and may reveal a more
optimal and beneficial wind-diesel power system for the community of Point Hope than the
configurations presented in this report. Higher wind penetration though requires greater system
complexity and control; these factors are inter-mutual and cannot be de-linked. But, high penetration
yields the greatest benefit of wind power and North Slope Borough may want to examine and consider
this option carefully before committing to a design objective.
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Appendix A – FAA’s Notice Criteria Tool, Site A
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Appendix B – FAA’s Notice Criteria Tool, Site B
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Appendix C – FAA’s Notice Criteria Tool, Sites C and D
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Appendix D – Power Grid, Point Hope
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Appendix E – Proposed Power Distribution One-Line Diagram
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Appendix F – Power Distribution System Expansion for Sites B and A
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