HomeMy WebLinkAboutCosmos Hills Hydroelectric Reconnaissance Report - Sep 2010 - REF Grant 2195413Alaska Village Electric CooperaƟve
Cosmos Hills Hydropower Study:
Reconnaissance Report
Alaska Energy Authority Renewable Energy Fund,
awarded grant #2195413
Looking towards Cosmos Hills in late March
(photo by Elia Sakeagak)
September 22, 2010
WHPacific, Inc.
300 W. 31st Ave
Anchorage, AK 99503
www.whpacific.com
AVEC Cosmos Hills Hydropower Page i 22 September 2010
Executive Summary
The Cosmos Hills-area hydropower sites of Dahl Creek, Wesley Creek, Cosmos Creek and Kogoluktuk
River appear to be aƩ racƟve economically and environmentally to develop, and are recommended for
further study. With esƟmated capaciƟes ranging between 430 kW and 3,200 kW, these three sites are
the most appropriately scaled for the energy needs of Shungnak, Kobuk and Ambler, and are located
relaƟvely close to exisƟng road and power line infrastructure.The three other potenƟal run-of-river
hydroelectric sites evaluated (Shungnak River, Jade Creek-East Fork near Ambler, and Canyon Creek near
Kiana), have been excluded from further consideraƟon because the expected installaƟon cost is too high
compared to the expected energy generated.
Dahl Creek:
The Dahl Creek project, with an esƟmated 430 kW of installed capacity (well above the
Shungnak-bout 350 kW), could serve the combined electric loads
of Shungnak and Kobuk for about half the year.
The installaƟon cost of the 430-kW Dahl Creek project is esƟmated to be $10.3 million in 2010
dollars (including 2 miles of new power line to connect to the exisƟng Shungnak-Kobuk power
line).
The hydroelectric plant site is located near the exisƟng Dahl Creek airstrip, and Kobuk-Bornite
road, which provides convenient access to Kobuk.
The Dahl Creek site is recommended for further study due to its projected energy output, and
relaƟve proximity to electric load/exisƟng infrastructure. During the summer 2010 field season,
a new stream gauge will be installed on Dahl Creek, the aerial photography and LIDAR mapping
will be done of the proposed project area, studies will be conducted on wetlands and fisheries
habitat, and geotechnical condiƟons/hazards.
Wesley Creek:
The Wesley Creek project, with an esƟmated 480 kW of capacity (well above the Shungnak-
50 kW), could serve the combined electric loads of
Shungnak and Kobuk for about half the year.
The Wesley Creek site is located about 5 miles northwest of Kobuk.
The installaƟon cost of the 480-kW Wesley Creek project is esƟmated to be $13 million in 2010
dollars (including 1.7 miles of new power line to connect to the exisƟng Shungnak-Kobuk power
line).
The Wesley Creek site is very accessible due to its locaƟon along the exisƟng road to Bornite,
and the powerhouse site would be located less than 2 miles from the exisƟng Shungnak-Kobuk
power line.
AVEC Cosmos Hills Hydropower Page ii 22 September 2010
The Wesley Creek site is recommended for further study due to its projected energy output, and
relaƟve proximity to electric load/exisƟng infrastructure.During the summer 2010 field season,
a new stream gauge will be installed on Wesley Creek, the aerial photography and LIDAR
mapping will be done of the proposed project area, studies will be conducted on wetlands and
fisheries habitat, and geotechnical condiƟons/hazards.
Cosmos Creek:
The Cosmos Creek project, with an esƟmated 950 kW of installed capacity (well above the 660
kW combined peak load of Ambler, Shungnak and Kobuk) and about 31 miles of new power line,
could serve the combined electric loads of Ambler, Shungnak and Kobuk for about half the year.
The Cosmos Creek site is located about 7 miles north of Shungnak.
The installaƟon cost of the 950-kW Cosmos Creek project is esƟmated to be $16.3 million in
2010 dollars (including 8 miles of new power line to connect to Shungnak). The total esƟmated
cost of a project with an addiƟonal 23 miles of power line that would jointly serve Ambler,
Shungnak and Kobuk would be $25.3 million.
The Cosmos Creek site presently has limited accessibility. Approximately 8 miles of new road
and power line would have to be constructed to connect the site to Shungnak.
The Cosmos Creek site is recommended for further study due to its projected energy output,
and relaƟve proximity to electric load/exisƟng infrastructure. During the summer 2010 field
season, a new stream gauge will be installed on Cosmos Creek, the aerial photography and
LIDAR mapping will be done of the proposed project area, studies will be conducted on wetlands
and fisheries habitat, and geotechnical condiƟons/hazards.
Kogoluktuk River:
The esƟmated capacity of the Kogoluktuk River run-of-river site is up to 3.2 MW (well above the
Shungnak-, and could serve the combined electric
loads of Ambler, Shungnak and Kobuk for most of the year. A run-of-river Kogoluktuk
hydroelectric project would not necessarily need to be built up to a capacity of 3.2 MW, as
proposed by the 2006 study by Shaw, Stone & Webster. A smaller installaƟon could be built at
the site, more opƟmized to local community electric loads. Area residents report that the
cascade of the Kogoluktuk River near Kobuk flows all year long, which means that some water
could be available for run-of-river hydroelectric generaƟon when other streams are frozen.
The Kogoluktuk River site is located about 7 miles northeast of Kobuk.
The installaƟon cost of a 3.2 MW Kogolukutuk River run-of-river project is esƟmated to be $32
million in 2010 dollars (not including the new access road and power line).
The Kogoluktuk River site presently has limited accessibility. Approximately 8.5 miles of new
road and power line would have to be constructed to connect the site to Kobuk.
AVEC Cosmos Hills Hydropower Page iii 22 September 2010
The Kogoluktuk River site is recommended for further study due to its projected energy output,
and potenƟal ability to produce hydropower for more than half the year. During the summer
2010 field season, a new stream gauge will be installed on the Kogoluktuk River, and the aerial
photography and LIDAR mapping will be done of the proposed project area.
Shungnak River:
The Shungnak run-of-river project, with an esƟmated 5.8 MW of installed capacity, could serve
the combined electric loads of Ambler, Shungnak and Kobuk for most of the year. A smaller
installaƟon could be built at the site, more opƟmized to local community electric loads.
The Shugnak River hydroelectric site is located about 9 miles northwest of the community of
Shungnak.
The installaƟon cost of a 5.8 MW Shungnak River run-of-river project is esƟmated to be $58
million in 2010 dollars (not including the new access road and power line).
The Shungnak River site presently has limited accessibility. Approximately 11.5 miles of new
road and power line would have to be constructed to connect the site to Shungnak.
The Shungnak River run-of-river hydropower site is not recommended for further study because
of its limited accessibility, and greater distance to a community electric load compared to the
four other hydropower sites near Shungnak and Kobuk. The Shungnak River also has a smaller
watershed, and thus less expected year-round flow, compared to the Kogoluktuk River.
Jade Creek - East Fork:
The Jade Creek-East Fork project, with an esƟmated 105 kW of installed capacity, could parƟally
serve of the electric load of Ambler for about half the year.
The Jade Creek-East Fork is located about 9 miles northwest of the community of Ambler.
The Jade Creek-East Fork site presently has limited accessibility. Approximately 9 miles of new
road and power line would have to be constructed to connect the site to Ambler.
The Jade Creek-East Fork hydropower site is not recommended for further study because of its
small esƟmated generaƟon capacity, limited accessibility, and relaƟvely long distance to a
community electric load.
Canyon Creek (Kiana):
The Canyon Creek project, with an esƟmated 150 kW of installed capacity, could parƟally serve
of the electric load of Kiana for about half the year.
The Canyon Creek site is located about 8 miles northeast of the community of Kiana.
AVEC Cosmos Hills Hydropower Page iv 22 September 2010
The Canyon Creek site presently has limited accessibility. Approximately 10 miles of new road
and power line would have to be constructed to connect the site to Kiana, would require a
crossing of the Squirrel River.
The Canyon Creek hydropower site is not recommended for further study because of its small
esƟmated generaƟon capacity, limited accessibility, and relaƟvely long distance to a community
electric load.
AVEC Cosmos Hills Hydropower Page v 22 September 2010
Contents
ExecuƟve Summary ........................................................................................................................................ i
1. IntroducƟon .......................................................................................................................................... 1
ExisƟng Energy Scenario ........................................................................................................................... 2
Future Energy Demand Trends in the Cosmos Hills Area ......................................................................... 4
Project Benefits ......................................................................................................................................... 6
Project Risks .............................................................................................................................................. 7
2. Hydroelectric Site Descriptions ............................................................................................................. 9
Dahl Creek ........................................................................................................................................... 12
Wesley Creek ...................................................................................................................................... 14
Cosmos Creek ...................................................................................................................................... 16
Jade Creek - East Fork ......................................................................................................................... 18
Canyon Creek (Kiana) .......................................................................................................................... 20
Shungnak River.................................................................................................................................... 22
Kogoluktuk River ................................................................................................................................. 24
3. Design ConsideraƟons......................................................................................................................... 27
Civil Works .............................................................................................................................................. 27
Dam or Weir ........................................................................................................................................ 28
Silt Basin/Forebay Tank ....................................................................................................................... 30
Intake/Trashrack ................................................................................................................................. 31
Penstock .............................................................................................................................................. 32
Tailrace ................................................................................................................................................ 33
Powerhouse ............................................................................................................................................ 33
Turbine and Generator ....................................................................................................................... 34
Governing and Electronic Control Systems ......................................................................................... 35
Electric Power Transmission/DistribuƟon .............................................................................................. 35
Access Roads and Other Infrastructure .................................................................................................. 36
OperaƟon and Maintenance ConsideraƟons .......................................................................................... 36
Ice Problems and MiƟgaƟon Measures .................................................................................................. 36
Induced Ice Cover FormaƟon .............................................................................................................. 37
Mechanical Ice Removal ..................................................................................................................... 37
AVEC Cosmos Hills Hydropower Page vi 22 September 2010
PrevenƟon of Ice AccumulaƟon on Intake Trashrack ......................................................................... 37
Penstock Icing ..................................................................................................................................... 38
Frozen Ground Issues .......................................................................................................................... 38
4. Preliminary Project Cost EsƟmates ..................................................................................................... 39
5. Economic Analysis ............................................................................................................................... 40
6. Land Ownership .................................................................................................................................. 41
7. Environmental Requirements ............................................................................................................. 43
Environmental Permits ........................................................................................................................... 43
FERC Licensing Requirements ............................................................................................................. 43
FERC Licensing ExempƟons ................................................................................................................. 44
Summer 2010 Environmental Studies .................................................................................................... 45
Office-Based Wetlands DelineaƟon .................................................................................................... 45
Fisheries and AquaƟc Resources Study............................................................................................... 45
Office-Based Cultural Resources Study ............................................................................................... 45
8. Public Outreach ................................................................................................................................... 46
9. Conclusions and RecommendaƟons ................................................................................................... 48
10. References .......................................................................................................................................... 50
Table 1: Electricity consumpƟon in the Upper Kobuk communiƟes (FY2008 PCE report) ........................... 3
Table 2: Delivered fuel prices for electricity generaƟon in Upper Kobuk (2009 AVEC data) ....................... 4
Table 3: PotenƟal run-of-river hydropower sites in the Upper Kobuk region ............................................ 10
Table 4: USGS stream flow data for Dahl Creek.......................................................................................... 10
Table 5: Run-of-river hydropower site selecƟon decision matrix............................................................... 11
Table 6: Dahl Creek site esƟmates .............................................................................................................. 13
Table 7: Cosmos Creek site esƟmates......................................................................................................... 17
Table 8: Wesley Creek site esƟmates ......................................................................................................... 15
Table 9: Jade Creek-East Fork site esƟmates .............................................................................................. 19
Table 10: Canyon Creek site esƟmates ....................................................................................................... 21
Table 11: Proposed Shungnak river hydroelectric alternaƟves (Shaw Stone & Webster, 2006) ............... 22
Table 12: Proposed Kogoluktuk River hydroelectric alternaƟves (Shaw Stone & Webster, 2006) ............ 24
Table 13: Turbine-generator unit price quotes from Canyon Hydro (March 2010, not incl. shipping from
SeaƩ le) ........................................................................................................................................ 34
Table 14: Power line cost esƟmates for Cosmos Hills projects (assumed installed cost of power lines:
$400,000/mile) ........................................................................................................................... 36
Table 15: PotenƟal costs of Upper Kobuk hydroelectric concepts ............................................................. 39
Table 16: Preliminary Results of HOMER economic model for Dahl and Cosmos hydropower sites ......... 40
AVEC Cosmos Hills Hydropower Page vii 22 September 2010
Figure 1: LocaƟon of possible hydroelectric sites in the Shungnak-Kobuk area (map by Paula Hansen) .... 9
Figure 2: Google Earth perspecƟve of proposed Dahl Creek hydroelectric site ......................................... 12
Figure 3: Topo map of proposed Dahl Creek hydroelectric site (map by Paula Hansen) ........................... 13
Figure 4: Google Earth perspecƟve of proposed Cosmos Creek hydroelectric site ................................... 16
Figure 5: Topo map of proposed Cosmos Creek hydroelectric site (map by Paula Hansen) ...................... 17
Figure 6: Google Earth perspecƟve of proposed Wesley Creek hydroelectric site .................................... 14
Figure 7: Topo map of proposed Wesley Creek hydroelectric site (map by Paula Hansen) ....................... 15
Figure 8: Google Earth perspecƟve of proposed Jade Creek East Fork hydroelectric site, and power line
connecƟng to Ambler ................................................................................................................. 18
Figure 9: Topo map of proposed Jade Creek-East Fork hydroelectric site (map by Paula Hansen) ........... 19
Figure 10: Google Earth perspecƟve of proposed Canyon Creek hydroelectric site, and power line
connecƟng to Kiana .................................................................................................................... 20
Figure 11: Topo map of proposed Canyon Creek hydroelectric site (map by Paula Hansen) .................... 21
Figure 12: Topo map of proposed Shungnak River hydroelectric site (map by Polarconsult Alaska, Inc.) 23
Figure 13: Topo map of proposed Kogoluktuk River hydroelectric site (map by Polarconsult Alaska, Inc.)
.................................................................................................................................................... 25
Figure 14: Kogoluktuk River (photo by Doug Vaught) ................................................................................ 26
Figure 15: Kogoluktuk River (photo by Doug Vaught) ................................................................................ 26
Figure 16: Typical layout of a small-scale, run-of-river hydroelectric plant (drawing by Jason McGrew) . 27
Figure 17: Diagram of typical diversion weir and intake structure for a small hydroelectric plant (drawing
by Brian Yanity) ........................................................................................................................... 28
Figure 18: Looking upstream at intake/diversion structure, with inflatable dam inflated, of the Power
Creek hydroelectric plant near Cordova, Alaska (photo courtesy of Cordova Electric
CooperaƟve) ............................................................................................................................... 29
Figure 19: Looking downstream at intake structure, with inflatable dam deflated, during the
construcƟon of the Power Creek hydroelectric plant near Cordova, Alaska (photo courtesy of
Cordova Electric CooperaƟve) .................................................................................................... 29
Figure 20: Diversion weir and intake structure under construcƟon at the Kasidaya Creek hydroelectric
plant near Skagway, Alaska (photo courtesy of Alaska Power & Telephone Company) ............ 30
Figure 21: Side-view diagram of forebay tank consisƟng of silt basin and trashrack (drawing by Brian
Yanity) ......................................................................................................................................... 31
Figure 22: Intake screens and pipe for the Black Bear Lake hydroelectric plant on Prince of Wales Island,
Alaska (photo courtesy of Alaska Power & Telephone Company) ............................................ 32
Figure 23: Penstock under construcƟon for McRoberts Creek hydroelectric plant (photo courtesy of
Polarconsult Alaska, Inc.) ............................................................................................................ 33
Figure 24: Small concrete powerhouse structure for 100-kW McRoberts Creek hydroelectric plant.
(photo courtesy of Polarconsult Alaska, Inc.) ............................................................................. 33
Figure 25: Turbine-generator set for 100-kW McRoberts Creek plant (photo courtesy of Polarconsult
Alaska, Inc.) ................................................................................................................................. 34
Figure 26: Possible hydroelectric sites and power line routes (map by Paula Hansen) ............................. 35
AVEC Cosmos Hills Hydropower Page viii 22 September 2010
Figure 27: Land ownership of possible hydroelectric sites and power line routes, with the Cosmos and
Dahl sites labeled (map by Paula Hansen)..................................................................................41
Figure 28: Land ownership of possible hydroelectric sites and power line routes, closer view of Cosmos
Hills area (map by Paula Hansen)..............................................................................................42
Figure 29: Public meeƟng in Ambler, March 24, 2010 (photo by Elia Sakeagak).......................................46
Figure 30: Public meeƟng in Shungnak, March 24, 2010 (photo by Elia Sakeagak)...................................47
Figure 31: Public meeƟng in Kobuk, 25 March 2010 (photo by Eva Harvey).............................................47
Appendices
Appendix A: Proposed Summer 2010 Work Plan
Hydrology
Mapping/surveying
Geotechnical and hazards review
Wetlands study
Fish and fish habitat survey
Cultural resources office study
Appendix B: Public MeeƟng Minutes;Ambler, Shungnak and Kobuk, March 24-25, 2010
Appendix C: Cosmos Hills Hydroelectric Feasibility Study FERC Requirements and Field Study
RecommendaƟons by Robin Reich of SolsƟce Alaska ConsulƟng, Inc.
AƩ achment A: Fish Stream InformaƟon
AƩ achment B: Agency and Stakeholder Contacts
Appendix D: Preliminary Project Cost EsƟmates by Chuck Clark of NANA WorleyParsons
Dahl Creek
Cosmos Creek
Appendix E: Federal Energy Regulatory Commission, Issued Preliminary Permits prepared by
Daniel Hertrich of Polarconsult Alaska, Inc.
Shungnak River
Kogoluktuk River
Appendix F: HOMER Computer Models of Hydroelectric Site Economics
Dahl Creek
Cosmos Creek
AVEC Cosmos Hills Hydropower Page 1 22 September 2010
1.Introduction
The Alaska Village Electric CooperaƟve (AVEC) is embarking on a Resource Assessment/Feasibility
Analysis/Conceptual Design project for a regional evaluaƟon of potenƟal hydropower sites and
associated transmission lines in the Kobuk River Valley, in collaboraƟon with NANA Regional
CorporaƟon. Seven sites are under evaluaƟon for their hydroelectric potenƟal. The Cosmos Hills group
of projects will potenƟally serve the communiƟes of Kobuk, Shungnak and Ambler. Canyon Creek near
Kiana is also being evaluated.
Currently, diesel-fuel power generaƟon is the only source of electricity for the upper Kobuk River
communiƟes of Ambler, Shungnak, and Kobuk. Possible renewable energy resources known to exist in
the area are wind, hydroelectric, and biomass energy. Wind energy resources for the region are already
being assessed by NANA and potenƟal sites for small-scale run-of-river hydroelectric plants, which do
not have a water storage dam, are worthy of exploraƟon. Run -of-river hydroelectric plants do not
require a large dam, and rely on the natural flow volume of the stream or river. Such faciliƟes tend to
have far less environmental impacts compared to convenƟonal dam-storage hydroelectric plants
because of the lack of a large arƟficial reservoir. With proper siƟng, construcƟon techniques, and
operaƟon and maintenance, run-of-river hydropower in the upper Kobuk River region could have
minimal impacts on fisheries and other subsistence resources.
The purpose of small hydroelectric plants would be to displace diesel fuel used for power generaƟon.
Hydroelectric power plants are expensive to build, but have no fuel costs. Run-of-river hydro sites in this
area could provide electricity from about mid-April unƟl early November. The challenge is that the peak
Ɵme of demand for electricity is winter, when the hydro plants would be producing no power. If the
hydro sites near Ambler, Shungnak and Kobuk prove viable, they will produce stable-priced power for
the long term, for about half the year. The projects, if viable, would come online in 2013 at the soonest,
assuming funding is available. A properly designed and well built hydro plant can last 50 years or more.
In 1979, the Alaska Power AdministraƟon (then a part of the US D epartment of Energy) conducted a
small hydropower evaluaƟon study of AVEC-served villages, which idenƟfied Jade Creek near Ambler,
and Cosmos Creek near Shungnak as potenƟal hydro sites. In 1981, the US Army Corps of Engineers,
Alaska District hired consultants to further evaluate small hydro power sites in Northwest Alaska. This
study further evaluated Jade Creek, Cosmos Creek, and Dahl Creek near Kobuk, and Canyon Creek near
Kiana. The 2006 Shaw Stone & Webster study for NovaGold conducted an iniƟal evaluaƟon of hydro
power potenƟal to support faciliƟes infrastructure and mining operaƟons at the proposed mine north of
the Cosmos Hills. The 2006 study also looked at Cosmos and Dahl creeks, and proposed three
alternaƟves each for developing the Shungnak and Kogoluktuk rivers, including proposals for dams. Due
to these very high construcƟon costs and possible environmental concerns, AVEC is not looking at
exploring the dam proposals expressed in the 2006 Shaw Stone & Webster report. However, AVEC,
NANA and other regional stakeholders are interested in further study and evaluaƟon of the run-of-river
opƟon at the Kogoluktuk site proposed by the 2006 study. This is because the river has much greater
flow volume than the creeks closer to Shungnak and Kobuk, and thus could offer an annual hydropower
generaƟon season longer than six months.
AVEC Cosmos Hills Hydropower Page 2 22 September 2010
In 2009, AVEC received $1,025,000 of pre-
Renewable Energy Fund (REF) program. This report represents the first of a series of documents to be
produced under the REF grant. It is a reconnaissance report which reviews work completed by others in
the past, updates cost esƟmates and reruns economic analyses. The goal of this document is to arrive at
a short list of hydro sites suitably size for village electric loads, which are recommended for feasibility-
level analysis, permiƫ ng and conceptual design. These future phases will be limited to the evaluaƟon of
only the recommended sites.
Existing Energy Scenario
AVEC is a member owned cooperaƟve electric uƟlity and typically owns and maintains the generaƟon,
fuel storage, and distribuƟon faciliƟes in the villages it serves. AVEC currently provides power to the
community of Shungnak, Ambler, and Kiana with diesel generators. Electricity generated by the AVEC
diesel power plant in Shungnak is sold to the Kobuk Valley Electric CooperaƟve via the Shungnak-Kobuk
power line to serve customers in Kobuk. AVEC-provided electricity staƟsƟcs are shown in Table 1 and
Table 2. FY2009 residenƟal, unsubsidized power rates were $0.69/kWh in Kiana, $0.80/kWh in Ambler,
$0.73/kWh in Shungnak, and $0.87/kWh in Kobuk. The communiƟes that would be served through this
project use diesel and heaƟng oil as the primary energy resources. They also use wood heat to a limited
degree. The load of the four villages listed above is highest during the winter months, with the bulk of
electricity consumed by residences and public faciliƟes such as schools. Lower power rates are possible
from hydroelectric power displacing diesel generaƟon.
AVEC Cosmos Hills Hydropower Page 3 22 September 2010 Table 1: Electricity consumpƟon in the Upper Kobuk communiƟes (FY2009 PCE report) Community EsƟmated total housing units Annual electricity consumpƟon, kWh Annual Diesel Consumed for Power GeneraƟon, gallons Electric Power Infrastructure Shungnak/ Kobuk 90 1,477,747 108,121 A 1,248-kW diesel power plant is located at Shungnak. The Kobuk Valley Electric CooperaƟve also has its own 75-kW back-up diesel power plant. The Kobuk Valley Electric CooperaƟve purchases power from AVEC over the Kobuk-Shungnak interƟe. According generaƟon staƟsƟcs, the peak demand recorded in 2009 at the Shungnak AVEC power plant is 343 kW, with an overall average plant load in 2009 of 174 kW. Ambler 83 1,189,915 90,941 A 982-kW diesel power plant is located in Ambler. AccorgeneraƟon staƟsƟcs, the peak demand recorded in 2009 at the Ambler AVEC power plant is 277 kW, with an overall average plant load in 2009 of 143 kW. Kiana 129 1,663,716 128,931 An 1163-kW diesel power plant is located in -of-year 2006 generaƟon staƟsƟcs, the peak demand recorded to date at the Kiana AVEC power plant is 365 kW, with an overall average plant load in 2009 of 188 kW.
AVEC Cosmos Hills Hydropower Page 4 22 September 2010
Table 2: Delivered fuel prices for electricity generaƟon in Upper Kobuk (2009 AVEC data)
Community Number of fuel
deliveries in
2009
Gallons of diesel
fuel delivered in
2009
Average annual cost
per gallon
Fuel-only cost of
electricity (as reported in
effecƟve April 1, 2010)
Shungnak 27 122,828 $4.35 $0.34/kWh
Ambler 15 110,001 $3.79 $0.24/kWh
Kiana 2 127,402 $3.17 $0.29/kWh
Future Energy Demand Trends in the Cosmos Hills Area
AVEC records indicate that the average electric load in Ambler increased an average of 1.7% per year
between 1991 and 2009, and the average load in Shungnak increased an average of 2.1% per year
between 1997 and 2009. These increases are presumably related to natural populaƟon growth, and
these trends are expected to conƟnue, barring any widespread new uses of electricity such as heaƟng.
The Ɵme of year for hydropower producƟon (May-October) in the Kobuk Valley does not correspond to
the Ɵme of peak electricity demand (November-April). However, surplus electricity generated during the
warmer months by the hydroelectric plant(s) could find new uses associated with local economic
development. It is certain that new customers for surplus electricity during the warm months would
increase the economic value of the hydroelectric projects. However, the ideas for using surplus energy
presented below are being discussed by NANA and other stakeholders in the region as community
economic development pilot projects. AVEC is not endorsing such energy uses merely to provide
jusƟficaƟon for the Cosmos Hills hydropower projects, but is merely aware of proposals by other
stakeholders in the region.
In decades past, small-scale jade mining was an important industry in the Upper Kobuk region.
NovaGold and NANA are presently discussing further mineral exploraƟon in the Ambler mining district,
about 20 miles
northeast of Kobuk. A commercial, large-scale mining operaƟon near the Cosmos Hills area would
certainly have a large demand for electric power, probably in excess of 20 MW. However, the reliability
ct, especially for long-term planning. This is because the
profitability of a mining operaƟon is dependent on volaƟle fluctuaƟons in the global prices for metals,
and many mines in the world have been shut down prematurely due to high operaƟng costs. At this
Ɵme, large-
power system planning for Ambler, Shungnak and Kobuk. However, mineral exploraƟon camps at Dahl
Creek and Bornite could offer a more short-term summer demand for locally-generated hydropower.
The Dahl Creek camp and airstrip are located only a half mile from the Dahl Creek powerhouse site, and
AVEC Cosmos Hills Hydropower Page 5 22 September 2010
is not yet connected to the local Shungnak-Kobuk power system. The Bornite camp is located 11 road
miles from the Dahl Creek powerhouse site, and thus is too far for an economical power line connecƟon.
However, a potenƟal 200-kW hydro site at Ruby Creek was idenƟfied about 2 miles north of Bornite by
the 2006 Shaw study. NANA and other regional stakeholders may invesƟgate Ruby Creek in future as a
source of power for the Bornite camp.
Electric heaters, for both space and water heaƟng, could be used during hydropower producƟon season
(April-October) to displace heaƟng oil. InterrupƟble loads, such as electric hot water heaters and electric
boilers, are a proven means for regulating output of a hydropower plant during the high-flow months of
summer. The hot water produced by the electric boilers could be uƟlized in individual faciliƟes or in
community-wide/district heaƟng systems. Heat produced by excess renewable power is typically first
used to heat criƟcal power generaƟon infrastructure such as standby/prime diesel powerplants. Once
electrical infrastructure heat requirements are met other facility or infrastructure heat requirements can
be met including schools, water treatment plants, community buildings or district heaƟng systems that
serve all faciliƟes. AVEC has experience operaƟng electric heaters with wind-diesel systems in
Quinhagak, Mekoryuk, Toksook Bay, Kasigluk, Chevak, Hooper Bay, Gambell and Savoonga.
Excess electric power is typically dispatched via a SCADA communicaƟon system to an electric boiler
located in a facility or heaƟng plant (in the case of district heaƟng). Within a facility such as a school or
water plant the electric boiler is typically piped as a secondary loop in series with the (fuel oil) boiler(s).
As electric heat is dispatched, based on the load requirements of the hydroelectric power system,
electric heat serves to pre-heat the fuel oil boilers and preclude their operaƟon and reducing fuel oil
consumpƟon.
The use of hot water produced from surplus hydroelectric power could be combined with biomass
boiler-driven district heaƟng system, which is being studied as part of the NIHA Upper Kobuk woody
biomass energy study. Woody biomass is being studied for uƟlizaƟon in the producƟon of thermal
energy for facility heaƟng as a supplement to fuel oil heaƟng. The scale of a biomass heaƟng system i s
driven by the available wood resource in the vicinity of the Upper-Kobuk/Cosmos Hills. Field work in the
summer of 2010 will begin to quanƟfy the wood resource and determine the sustainable yield of the
area. If the wood resource is determined be sustainable on a large scale then the uƟlizaƟon of the heat
in community wide or district heaƟng systems may prove to be feasible.
In terms of a seasonal thermal energy plan for village heaƟng needs, excess hydroelectric power can be
used during the early-summer and early-fall seasons (May through September/October) with biomass
heaƟng for the winter and early-spring seasons (November through April/May). Facility thermal needs
are lower during the summer months however domesƟc water heaƟng and water treatment system
heaƟng are sƟll needed. Peak thermal demands for the Upper-Kobuk communiƟes are esƟmated be as
follows based on commercial facility boiler capaciƟes and residenƟal esƟmates:
- Kobuk = 3-4 mBTU/hr = 900-1200 kW-thermal
- Shungnak = 4-5 mBTU/hr = 1200-1500 kW-thermal
- Ambler = 5-6 mBTU/hr = 1500-1800 kW-thermal
AVEC Cosmos Hills Hydropower Page 6 22 September 2010
According to esƟmates in the NANA Region Strategic Energy Plan (NANA Pacific, 2008), Shungnak and
Kobuk combined annually consume about 160,000 gallons of diesel heaƟng fuel . Assuming that one
gallon of diesel heaƟng oil is equivalent to 30 kWh of surplus hydropower used for electric heat,
Shungnak and Kobuk combined annually consume the equivalent of 4,800,000 kWh for total heaƟng
needs. Assuming that 75% of the total heat energy demand of both communiƟes happens during the
coldest months of no hydropower producƟon or is in buildings that could not be conveniently connected
to electric heat, this sƟll leaves 40,000 gallons of diesel heaƟng fuel that could be displaced with
hydropower when the stream or river is flowing. If Ambler were connected by power line to the
Shungnak-Kobuk system, an addiƟonal 35,000 gallons of heaƟng fuel could be displaced using the same
assumpƟons.Electricity sold by AVEC for heaƟng purposes would most likely be sold at an interrupƟble
rate that is lower than the normal retail rate. The cost of this interrupƟble power for heaƟng is unknown
at this Ɵme, and would depend on the cost of the hydroelectric plant and the cost of electric heat
infrastructure. The 1,200,000 kWh to 2,500,000 kWh of surplus electricity needed each year to power
electric heaters during the autumn and spring shoulder seasons could possibly be available from a run-
of-river hydropower development on the Kogoluktuk River, but likely not from the smaller sites of Dahl,
Wesley, and Cosmos creeks (see secƟon 2 below).
A coordinated effort between the Upper Kobuk biomass and Cosmos Hills hydroelectric studies will help
to address the annual thermal needs of the Upper Kobuk communiƟes. As the quanƟty of surplus
hydroelectric power becomes more defined the quanƟty of the annual biomass energy harvest (cords of
wood) can be adjusted accordingly. Through the economic analysis of each study the cost of thermal
energy from wood and water resources will also guide future efforts to develop each resource. Another
issue being discussed in the NANA region is food security and local agriculture uƟlizing greenhouses with
heat and lighƟng powered by hydroelectric electricity generated from the Cosmos Hills plants. Growing
season corresponds to the Ɵme of year of run-of-river hydroelectric power output.
Project Beneϐits
The primary benefit of the hydropower development in the Cosmos Hills is the reducƟon of the amount
of diesel fuel used for power generaƟon. Diesel fuel is the primary source of heat and power generaƟon
for all of the communiƟes in this region. As a result of complex logisƟcs and the need for on -site fuel
storage, retail fuel costs are exceedingly high. The region suffers from some of the highest prices in the
naƟon for electricity.
The anƟcipated benefits of the Cosmos Hills hydroelectric project(s) are many; primary among these are
meeƟng long term regional energy vision and reducing the negaƟve impact
of the cost of energy on the NANA Region by providing a renewable energy alternaƟve. This project
would have many environmental benefits resulƟng from a reducƟon of hydrocarbon use. These benefits
include:
Reduced potenƟal for fuel spills or contaminaƟon during transport, storage, or use (thus
protecƟng vital water and subsistence food sources)
Improved air quality
Decreased contribuƟon to greenhouse gas emissions from fossil fuel use
Minimizing risk associated with the inability of river barges to reach Upper Kobuk communiƟes
StabilizaƟon of electric energy costs
AVEC Cosmos Hills Hydropower Page 7 22 September 2010
NANA Regional CorporaƟon has a vision for the NANA region to be 75% reliant on regionally available
energy resources for heaƟng and power generaƟon by the year 2030 . It is their vision to decrease the
need for transportaƟon fuel imported into the region by 50% by the year 2030. As part of this vision,
imported fossil fuels would be relied upon only as emergency/back-up fuel. AVEC has its own desire to
greatly reduce the amount of diesel consumed in its rural power plants, and is partnering with NANA to
implement more renewable energy projects in the region. Regionally available resources include
renewables such as hydropower, solar, wind, geothermal, biomass, hydroge n and fuel cells; alternaƟve
fuels such as regionally available coal to gas resources; and regional fossil fuels such as natural gas and
energy vision is on what can be developed locally, within its region.
disadvantaged residents are forced to choose between heaƟng their homes and
buying groceries. The impacts felt within the NANA region are magnified by the addiƟonal costs
associated with bulk fuel shipping, and the poor economies of scale in power generaƟon and
distribuƟon for such small, isolated communiƟes. With more affordable energy available in the villages,
community stability and wellness and helping to stem the Ɵde of rural migraƟon.
Project Risks
LogisƟcal challenges and delays associated with fieldwork in our remote rural Alaskan communiƟes
represent potenƟal barriers to the success of the proposed project. The tributaries proposed as sites for
this project are remotely located from the nearest hub airport, and are reachable by ATV trail,
helicopter, small airplane, snowmachine, or seasonally available barges which travel on local waterways
to bring supplies, fuel and other goods to the villages. In recent years, it has been increasingly difficult
for barges on the Kobuk River to reach these communiƟes, with the river depth being insufficient for
much of the summer. The proposed hydroelectric projects are likely to require the construcƟon of new
access roads, or upgrades to exisƟng roads and trails. The very remote nature of the sites makes
collecƟon of topography, geology and hydrology data Ɵme consuming and expensive. Because of
changeable weather condiƟons and the complex logisƟcs involved in transporƟng materials to such
remote locaƟons, the season for barge transport is extremely limited, and shipping delays are quite
common. However, AVEC and NANA are accustomed to dealing with such limitaƟons, and its proposed
partners also have extensive experience in addressing the difficulƟes associated with conducƟng
business in such challenging condiƟons. Shipping arrangements for research equipment and supplies will
be made with ample allowance for possible delays, and sufficient flexibility will be included in fieldwork
schedules to ensure on-Ɵme and successful compleƟon of all project phases. AVEC will only select
contractors and transportaƟon providers with remote construcƟon experience in Northwest Alaska.
The construcƟon and operation of hydroelectric plants in cold climates also presents the possibility of
special problems such as working in permafrost soils and icing problems in rivers and streams. The
proposed Cosmos Hills project sites wil
North America has yet been built this far north. The AVEC project should study the experience of
hydropower in other cold regions of the world, such as exisƟng hydroelectric plants in Canad
and Northwest Territories or in Russia and Scandinavia, by reviewing technical arƟcles and publicaƟons.
AVEC Cosmos Hills Hydropower Page 8 22 September 2010
Both intake ice and penstock icing problems have the potenƟal to cause significant project operaƟonal
expense and loss of power generaƟon capacity during the 'shoulder' months of May and October.
AVEC Cosmos Hills Hydropower Page 9 22 September 2010
2.Hydroelectric Site Descriptions
The locaƟons of the conceptual Shungnak, Cosmos, Wesley, Dahl, and Kogoluktuk hydroelectric plant
sites, as well as the communiƟes of Shungnak and Kobuk, are shown on the map in Figure 1.
Figure 1: LocaƟon of possible hydroelectric sites in the Shungnak-Kobuk area (map by Paula Hansen)
Due to the cold winters of the Kobuk River region, small run-of-river hydroelectric plants would be able
to produce power for about six months of the year: between mid-April and early November. However,
the winter months of low or no stream-flow coincide with the strongest reported winds in the region, so
the combined development of wind and hydroelectric power generaƟon could potenƟally reduce diesel
fuel use in Ambler, Shungnak and Kobuk and possibly even Kiana and Noorvik. PotenƟal wind energy
sites could exist in the Cosmos Hills area near proposed power line routes, but li Ʃ le is known of the local
wind resources at this Ɵme. CharacterisƟcs of the seven potenƟal run-of-river hydroelectric sites in the
Cosmos Hills area are listed in Table 3.
AVEC Cosmos Hills Hydropower Page 10 22 September 2010
Table 3: PotenƟal run-of-river hydropower sites in the Upper Kobuk region
Hydroelectric
site
Drainage
area, sq.
mi.
Installed
capacity,
kW
Est.
annual
energy,
MWh
Est. net
head, Ō .
Est.
hydraulic
capacity,
cfs
# of
units
Turbine
type
Dahl Creek 9 430 1,800 220 35 1 Crossflow
Cosmos Creek 13 950 3,700 290 50 1 VerƟcal
Pelton
Wesley Creek 6 480 2,200 300 25 1 Pelton or
Turgo
Jade Creek-East
Fork
5 100 250 350 5 1 Horizontal
Pelton
Canyon Creek 10 150 400 150 20 1 Crossflow
Shungnak River 200 5,800 19,900 138 600 2 Francis
Kogoluktuk River 290 3,200 12,000 57 800 2 Francis
Table 4: USGS stream flow data for Dahl Creek
Month 1986-2008 USGS Dahl Creek mean of
monthly discharge at Kobuk (cfs)
January 4.5
February 3.9
March 3.5
April 4.0
May 54
June 59
July 37
August 62
September 45
October 28
November 11
December 6.3
Annual mean 26.5
For the Dahl and Cosmos sites preliminary cost esƟmates for are described in more detail in Appendix D,
and HOMER computer simulaƟon summary reports are given in Appendix F. Topographical informaƟon,
such as net head esƟmates and penstock lengths, were esƟmated using Google Earth. Hydrologic
informaƟon and design flows were esƟmated using data from the exisƟng USGS stream gauge on Dahl
Creek (shown in Table 4 above), located near the Dahl Creek airstrip about a half mile downstream from
the proposed powerhouse site. A full hydrological analysis, including the risk of dry years causing a
reducƟon in expected power generaƟon, will be evaluated aŌer sufficient stream flow data has been
collected from Cosmos Hills streams
AVEC Cosmos Hills Hydropower Page 11 22 September 2010
As shown in 5, Dahl Creek, Wesley Creek, Cosmos Creek, and Kogoluktuk River appear to be the most
aƩracƟve economically and environmentally to develop, and are recommended for further study. With
esƟmated capaciƟes of 430 kW and 950 kW respecƟvely, these two sites are the most appropriately
scaled for the energy needs of Shungnak, Kobuk and Ambler, and are located relaƟvely close to exisƟng
road and power line infrastructure. The proposed installed capacity of Dahl Creek is 430 kW, well above
the Shungnak-
Creek is 950 kW, well above the 660 kW combined peak load of Ambler, Shungnak and Kobuk. However,
during the April-October period of hydropower generaƟon, the highest combined load of Ambler,
Shungnak and Kobuk is about 530-kW (in October), with a combined July peak of about 370 kW. The
opƟons of either Cosmos Creek or Dahl Creek serving combined loads of Ambler, Shungnak and Kobuk
during hydropower generaƟon season will be explored in the economic analysis secƟon.
The proposed dams on the Shungnak River and Kogoluktuk River would have esƟmated capital costs
ranging between $50 million and $160 million each, and generaƟon capaciƟes ranging between 7 and 13
MW per site. These capital costs and generaƟon capaciƟes are far too large for village power. The
esƟmated cost and capacity of run-of-river opƟons at Shungnak River ($58 million for 5.8 MW) and
Kogoluktuk River ($32 million for 3.2 MW) also appear too large for community energy needs of
Shungnak and Kobuk. However, AVEC and other regional stakeholders are interested in further study of
the Kogoluktuk River, which offers the possibly of exploitable flow for more than six months a year, and
is located closer to a community load than the Shungnak River. The two other potenƟal run-of-river
hydroelectric sites, Jade Creek-East Fork near Ambler and Canyon Creek near Kiana, have been excluded
from further consideraƟon because the expected installaƟon cost is too high compared to the expected
energy generated.
Table 5: Run-of-river hydropower site selecƟon decision matrix
Criteria, each weighted 20%, and
ranked 1 (worst) to 5 (best):
Proximity to
electric
load/exisƟng
power line
Ease of
access/
proximity to
exisƟng road
Appropriate
installed capacity,
relaƟve to size of
exisƟng electric
demand
EsƟmated
cost of
installaƟon
per kW
Expected
length of
hydropower
generaƟon
season
Total
score
Dahl Creek 5 5 5 4 3 4.4
Wesley Creek 5 5 5 3 3 4.2
Cosmos Creek 3 3 4 3 3 3.2
Kogoluktuk River (run-of-river) 2 2 2 5 5 3.2
Shungnak River (run-of-river) 2 2 2 5 4 3.0
Jade Creek East Fork 2 2 4 1 2 2.2
Canyon Creek 1 1 4 1 3 2.0
AVEC Cosmos Hills Hydropower Page 12 22 September 2010
Dahl Creek
The 1981 Corps study considered a 140-kW hydroelectric installaƟon on Dahl Creek to serve both Kobuk
and Shungnak, at a site located about 3 miles north of Kobuk (shown in Figure 2 and Figure 3). The
average annual plant factor of this site was esƟmated to be only 0.28, with no power producƟon
occurring from December through April. A Turgo-type turbine was recommended. The environmental
constraints listed in the report are whitefish and grayling in the creek. The 2006 Shaw report esƟmated a
larger hydro plant configuraƟon of 500 kW capacity, with design flow increased to 35 cfs (up from 10
cfs). For the 35 cfs design flow, the penstock pipe inner diameter (I
recommended a 430-kW crossflow turbine. This study is using the assumpƟons listed in Table 6. The
hydroelectric plant site is located near the exisƟng Dahl Creek airstrip, and Kobuk-Bornite road, which
provides convenient access to Kobuk.
Figure 2: Google Earth perspecƟve of proposed Dahl Creek hydroelectric site
AVEC Cosmos Hills Hydropower Page 13 22 September 2010
Figure 3: Topo map of proposed Dahl Creek hydroelectric site (map by Paula Hansen)
Table 6: Dahl Creek site esƟmates
Watershed drainage area (sq. mi.) 9
Installed capacity (kW) 430
Est. annual energy (MWh) 1,800
Est. net head (Ō.) 220
Est. hydraulic capacity (cfs) 35
Number of turbine-generator units 1
Turbine type Crossflow
Est. penstock pipe I.D. (inches) 32
Est. penstock length (Ō.) 7,800
Est. power line distance (miles) 2
Recommended for further study? Yes, due to projected energy output, and relaƟve
proximity to electric load/exisƟng infrastructure
The installaƟon cost of the 430-kW Dahl Creek project is esƟmated to be $10.3 million in 2010 dollars
(including 2 miles of new power line to connect to the exisƟng Shungnak-Kobuk power line). Assuming a
50-year plant life, the HOMER soŌware esƟmates a cost of electricity from Dahl Creek of $0.43/kWh.
AVEC Cosmos Hills Hydropower Page 14 22 September 2010
Wesley Creek
The potenƟal Wesley Creek hydroelectric site is located just west of Dahl Creek, about 5 miles northwest
of Kobuk, as shown in Figure 4 and Figure 5. The Wesley Creek drainage is very accessible due to its
locaƟon along the exisƟng road to Bornite, and the powerhouse site would be located less than 2 miles
from the exisƟng Shungnak-Kobuk power line. Flowing water was observed during the March 25, 2010
site visit, and the size and locaƟon of the creek merits the installaƟon of a stream gauge to start
collecƟng hydrological data. This study is using the assumpƟons listed in Table 7.
Figure 4: Google Earth perspecƟve of proposed Wesley Creek hydroelectric site
AVEC Cosmos Hills Hydropower Page 15 22 September 2010
Figure 5: Topo map of proposed Wesley Creek hydroelectric site (map by Paula Hansen)
Table 7: Wesley Creek site esƟmates
Watershed drainage area (sq. mi.) 6
Installed capacity (kW) 480
Est. annual energy (MWh) 2,200
Est. net head (Ō.) 300
Est. hydraulic capacity (cfs) 25
Number of turbine-generator units 1
Turbine type Pelton or Turgo
Est. penstock pipe I.D. (inches) 28
Est. penstock length (Ō.) 12,000
Est. power line distance (miles) 1.7
Recommended for further study? Yes, due to projected energy output, and relaƟve
proximity to electric load/exisƟng infrastructure
The installaƟon cost of the 480-kW Wesley Creek project is esƟmated to be $13 million in 2010 dollars
(including 1.7 miles of new power line to connect to the exisƟng Shungnak-Kobuk power line). This
figure is based on the cost esƟmate for the similar Dahl Creek site, with an increased penstock cost due
to its longer length at Wesley Creek. Assuming a 50-year plant life, the HOMER soŌware esƟmates a cost
of electricity from Wesley Creek of $0.44/kWh.
AVEC Cosmos Hills Hydropower Page 16 22 September 2010
Cosmos Creek
The Cosmos Creek site, shown in Figure 6 and Figure 7, is roughly 7 miles north of Shungnak. The 1981
Corps study proposed a 144-kW installaƟon on Cosmos Creek, with an esƟmated average annual plant
factor of only 0.26. A Turgo-type turbine was recommended. No power producƟon would occur from
December through April, and the environmental constraints listed are the presence of whitefish and
arcƟc grayling in the stream. The 2006 Shaw Stone & Webster report proposed a 1,000-kW run-of-river
installaƟon, with an average annual energy producƟon of 2,900 MWh with a much higher esƟmated
design flow (50 cfs) than the 1981 study (10 cfs). Also, the net head was esƟmated to be 290 feet, up
from 200 feet proposed by the 1981 study. Based on USGS and Google Earth topographical informaƟon
available that confirms the 2006 study esƟmate, a For the
assuming an overall fricƟonal head loss of 10% for the enƟre length of the pipe and a roughness
c -
kW verƟcal Pelton turbine. This study is using the assumpƟons listed in Table 8.
Figure 6: Google Earth perspecƟve of proposed Cosmos Creek hydroelectric site
AVEC Cosmos Hills Hydropower Page 17 22 September 2010
Figure 7: Topo map of proposed Cosmos Creek hydroelectric site (map by Paula Hansen)
Table 8: Cosmos Creek site esƟmates
Watershed drainage area (sq. mi.) 13
Installed capacity (kW) 950
Est. annual energy (MWh) 3,700
Est. net head (Ō.) 290
Est. hydraulic capacity (cfs) 50
Number of turbine-generator units 1
Turbine type VerƟcal Pelton
Est. penstock pipe I.D. (inches) 34
Est. penstock length (Ō.) 10,600
Est. power line distance (miles) 8
Recommended for further study? Yes, due to projected energy output, and relaƟve
proximity to electric load/exisƟng infrastructure
The installaƟon cost of the 950-kW Cosmos Creek project is esƟmated to be $16.3 million in 2010 dollars
(including 8 miles of new power line to connect to Shungnak). An addiƟonal 23 miles of power line
would be needed to connect to Ambler, at a cost esƟmated to be $9 million. Therefore, the total
esƟmated cost of a project that would serve Ambler, Shungnak and Kobuk would be $25.3 million.
Assuming a 50-year plant life, the HOMER soŌware esƟmates a cost of electricity from Cosmos Creek of
$0.49/kWh (serving all three communiƟes).
AVEC Cosmos Hills Hydropower Page 18 22 September 2010
Jade Creek - East Fork
The East Fork site of Jade Creek is located about 9 miles northwest of Ambler, as shown in Figure 8 and
Figure 9. There is no exisƟng road access near the potenƟal project area or power line corridor. The Jade
Creek-East Fork site appears to have too small of an expected capacity (105 kW) to warrant the
construcƟon of a 9-mile power line to Ambler. The cost of developing such a facility is likely to be too
high for the amount energy produced. This study is using the assumpƟons listed in Table 9.
Figure 8: Google Earth perspecƟve of proposed Jade Creek East Fork hydroelectric site, and power line connecƟng to Ambler
AVEC Cosmos Hills Hydropower Page 19 22 September 2010
Figure 9: Topo map of proposed Jade Creek-East Fork hydroelectric site (map by Paula Hansen)
Table 9: Jade Creek-East Fork site esƟmates
Watershed drainage area (sq. mi.) 5
Installed capacity (kW) 100
Est. annual energy (MWh) 250
Est. net head (Ō.) 350
Est. hydraulic capacity (cfs) 5
Number of turbine-generator units 1
Turbine type Horizontal Pelton
Est. penstock pipe I.D. (inches) 12
Est. penstock length (Ō.) 9,300
Est. power line distance (miles) 9
Recommended for further study? No, due to low projected energy output, and relaƟvely
long distance to electric load/exisƟng infrastructure
AVEC Cosmos Hills Hydropower Page 20 22 September 2010
Canyon Creek (Kiana)
Canyon Creek is located about 8 miles north of Kiana as shown in Figure 10 and Figure 11, and about 60
miles west of Ambler. There is no exisƟng road access near the potenƟal project area or power line
corridor, and construcƟon of a power line and new road to the site would require a crossing of the
Squirrel River. It is assumed that Canyon Creek would provide power to Kiana only. Like Jade Creek,
Canyon Creek appears to have too small of an expected capacity (150 kW) to warrant the construcƟon
of such a long power line. This study is using the assumpƟons listed in Table 10.
Figure 10: Google Earth perspecƟve of proposed Canyon Creek hydroelectric site, and power line connecƟng to Kiana
AVEC Cosmos Hills Hydropower Page 21 22 September 2010
Figure 11: Topo map of proposed Canyon Creek hydroelectric site (map by Paula Hansen)
Table 10: Canyon Creek site esƟmates
Watershed drainage area (sq. mi.) 10
Installed capacity (kW) 150
Est. annual energy (MWh) 400
Est. net head (Ō.) 150
Est. hydraulic capacity (cfs) 20
Number of turbine-generator units 1
Turbine type Crossflow
Est. penstock pipe I.D. (inches) 24
Est. penstock length (Ō .) 8,000
Est. power line distance (miles) 9
Recommended for further study? No, due to low projected energy output, and relaƟvely
long distance to electric load/exisƟng infrastructure
AVEC Cosmos Hills Hydropower Page 22 22 September 2010
Shungnak River
--foot high dam) or a
-foot high dam) hydroelectric development on the Shungnak River. The
proposed hydroelectric site is located about 8.5 miles northwest of the community of Shungnak, as
shown in Figure 12. In either case, the installaƟon would produce no power from January through April.
A 5.8 MW run-of-river (with no dam) hydroelectric plant was also proposed for the Shungnak River, but
was judged to not be as economical as a dam-storage facility. An 11.5-mile power line would need to be
built connecƟng Shungnak River site and the community of Shungnak. Key figures for each of the three
Shungnak River alternaƟves are shown in Table 11.
Table 11: Proposed Shungnak river hydroelectric alternaƟves (Shaw Stone & Webster, 2006)
Site Hydroelectric
Plant
ConfiguraƟon
Installed
capacity,
kW
Est.
annual
energy,
MWh
Dam
height at
max
secƟon,
Ō.
Est. net
head,
Ō.
Reservoir
full
volume,
acre-feet
EsƟmated
capital
installaƟon
cost, million
$
EsƟmated
capital cost
per kW
capacity
installed, $
Shungnak
River
Drainage
area: 200
sq. mi.
Hydraulic
capacity:
600 cfs
Storage dam,
full-sized
13,000 52,400 195 310 428,000 83.7 6,900
Storage dam,
reduced-sized
10,600 42,700 135 253 99,000 62 5,850
Run-of-river 5,800 19,900 n/a 138 n/a 58 10,000
AVEC Cosmos Hills Hydropower Page 23 22 September 2010
Figure 12: Topo map of proposed Shungnak River hydroelectric site (map by Polarconsult Alaska, Inc.)
AVEC Cosmos Hills Hydropower Page 24 22 September 2010
Kogoluktuk River
The 1979 DOE study references a 1966 statewide inventory of hydropower sites conducted by the
Alaska Power AdministraƟon, which proposed a 8,400-kW (8.4 MW) hydroelectric plant on the
Kogoluktuk River. This project included a 205-foot high concrete arch dam to provide 100% stream flow
regulaƟon. However, the DOE study also describes the possibility of a much smaller installaƟon where
the Kogoluktuk River flows through a narrow canyon about 7 miles northeast of Kobuk (shown in Figure
13, Figure 14 and Figure 15). The 2006 study by Shaw Stone & Webster propo -
(with a 175-hydroelectric development at
the same locaƟon on the Kogoluktuk River. In either case, the installaƟon would produce no power from
January through April. A 3.2 MW run-of-river (with no dam) hydroelectric plant was also proposed for
the Kogoluktuk River. Key figures for each of the three Kogoluktuk River alternaƟves are shown in Table
12.
Table 12: Proposed Kogoluktuk River hydroelectric alternaƟves (Shaw Stone & Webster, 2006)
Site Hydroelectric
Plant
ConfiguraƟon
Installed
capacity,
kW
Est.
annual
energy,
MWh
Dam
height
at max
secƟon,
Ō.
Est.
net
head,
Ō.
Reservoir
full
volume,
acre-feet
EsƟmated
capital
installaƟon
cost,
million $
EsƟmated
capital
cost per
kW
capacity
installed,
$
Kogoluktuk
River
Drainage
area: 290
sq. mi.
Hydraulic
capacity:
800 cfs
Storage dam,
full-sized
11,700 51,500 175 210 1,228,000 158.2 13,500
Storage dam,
reduced-
sized
7,000 30,600 90 125 40,000 80 11,400
Run-of-river 3,200 12,000 n/a 57 n/a 32 10,000
possibly of exploitable flow for more than six months a year, and is located closer to a community load
than the Shungnak River. As described on page 5 of this report, the combined maximum winter heaƟng
load of Shungnak and Kobuk is the electrical equivalent of 2 to 3 MW. If electric heaters, combined with
exisƟng oil heaters as backup, were used extensively in both communiƟes, the hydropower from
Kogoluktuk River could be sufficient to supply a significant amount of heat energy demand in autumn,
late winter and early spring. However, it is not yet known if the flow characterisƟcs of the site would
allow for safe, reliable operaƟon during the cold season. Therefore, it is recommended that a stream
gauge be installed on the Kogoluktuk River, just upstream from the narrow canyon area.
AVEC Cosmos Hills Hydropower Page 25 22 September 2010
Figure 13: Topo map of proposed Kogoluktuk River hydroelectric site (map by Polarconsult Alaska, Inc.)
AVEC Cosmos Hills Hydropower Page 26 22 September 2010
Figure 14: Kogoluktuk River (photo by Doug Vaught)
Figure 15: Kogoluktuk River (photo by Doug Vaught)
AVEC Cosmos Hills Hydropower Page 27 22 September 2010
3.Design Considerations
The purpose of this secƟon is to provide a more detailed descripƟon of run-of-river hydropower
infrastructure and equipment, and provide examples of designs of operaƟng Alaska run-of-river faciliƟes
of similar scale.
Civil Works
A typical layout of a small-scale, run-of-river hydroelectric plant is shown in Figure 16.
Figure 16: Typical layout of a small-scale, run-of-river hydroelectric plant (drawing by Jason McGrew)
PredicƟo
geotechnical/geology site study would be required for a comprehensive feasibility study, as well as
recommendaƟons for protecƟon from natural hazards (rock fall, flooding, avalanches, etc).
The cold-climate problems of the site (low winter stream-flow, intake ice problems, and penstock icing)
will not preclude hydropower development, but these Kobuk Valley sites demand special design
consideraƟons and maintenance procedures. While hydroelectric plants in this area could produce
reliable power for at least six months of the year, design must include accommodaƟon of winter season
AVEC Cosmos Hills Hydropower Page 28 22 September 2010
Also important will be maintaining minimal stream flow in the exisƟng creek channel , in the stream
reach between the intake and tailrace. AVEC will work with regulatory agencies to determine what this
minimum flow requirement would be.
Dam or Weir
For a small-scale, run-of-river hydroelectric plant unobtrusive dam-like
structure used to raise the water level and ensure the intake is deep enough for s design flow.
At least part of the weir structure could be made from natural rock elements found in the streambed. A
diversion weir is a small dam whose purpose is to increase water level near the hydroelectric plant
intake, and not to store a substanƟal volume of water. Figure 17 is a diagram of a typical diversion weir
and intake structure for a micro-hydroelectric plant.
Figure 17: Diagram of typical diversion weir and intake structure for a small hydroelectric plant (drawing by Brian Yanity)
The Cosmos Hills projects are being evaluated primarily as run-of-river hydroelectric plants. Large
storage dams in remote arcƟc areas pose significant logisƟcal and construcƟon cost problems, and will
not be considered for the Dahl, Cosmos, Wesley, Canyon or Jade Creek-East Fork sites. Small-scale
inflatable dams, which are periodically deflated during high water levels and to allow sediment passage,
have been used successfully in Cordova, Alaska and at various recent run-of-river hydropower
developments in BriƟsh Columbia. Shown in Figure 18 and Figure 19, is the intake structure for the
Power Creek hydroelectric plant near Cordova, which uses an inflatable rubber dam, made by
Bridgestone. Another variaƟon on an inflatable dam, the Obermeyer gate installed in 2008 at the
Kasidaya Creek near Skagway is shown in Figure 20.
ConstrucƟng a weir made from rock Gabions is a simpler approach than using inflatable dams, and it is
this type of weir assumed for the Dahl Creek and Cosmos Creek project cost esƟmates used in this
report.
AVEC Cosmos Hills Hydropower Page 29 22 September 2010
Figure 18: Looking upstream at intake/diversion structure, with inflatable dam inflated, of the Power Creek hydroelectric
plant near Cordova, Alaska (photo courtesy of Cordova Electric CooperaƟve)
Figure 19: Looking downstream at intake structure, with inflatable dam deflated, during the construcƟon of the Power Creek
hydroelectric plant near Cordova, Alaska (photo courtesy of Cordova Electric CooperaƟve)
AVEC Cosmos Hills Hydropower Page 30 22 September 2010
Figure 20: Diversion weir and intake structure under construcƟon at the Kasidaya Creek hydroelectric
plant near Skagway, Alaska (photo courtesy of Alaska Power & Telephone Company)
Silt Basin/Forebay Tank
slows down the flow speed of the water entering the intake. Such a silt
basin is needed for many Alaska rivers and streams, which have a high
eroded sediment. Much of this water-borne sediment is composed of hard abrasive materials, which can
cause expensive damage to the turbine. Also, enough sediment may cause blockage of the intake. A
sluice-type spillway, directed downstream back into the stream or river, can be used to periodically
clean out the silt basin and handle overflow condiƟons.
that incorporates an intake trashrack. A side-view diagram of typical forebay tank for a micro-hydro
plant is shown in Figure 21.
speed of the water entering the intake, so that at least some of the floaƟng sediment parƟcles will seƩ le
on basin floor instead of entering the penstock. Such a silt basin is needed for a stream with a high
amount of eroded sediment. Some of this waterborne sediment could be composed of hard abrasive
materials such as sand, which can cause damage to the turbine. A water turbine may have to be
replaced in as early as liƩ le as a few years if silt and sand are not properly controlled. The finest type of
stream sediment, glacial flour, can easily pass through the silt basin and be carried through the turbine.
However, glacial flour generally causes less damage than coarser parƟcles of stream sediment due to its
smaller size. The basin would be effecƟve in catching sand and large -grained parƟcles. The nature of
load is site-specific, and samples of water-borne sediment need to be taken at each of
the streams under study.
AVEC Cosmos Hills Hydropower Page 31 22 September 2010
Figure 21: Side-view diagram of forebay tank consisƟng of silt basin and trashrack (drawing by Brian Yanity)
Intake/Trashrack
made from metal bars, in order to block large debris (large rocks, pieces of wood, etc.) that cannot be
captured by a seƩling basin. The locaƟon of the intake structure (including the weir and forebay) would
be as high up on the valley slope as possible. -rack is shown in Figure 22.
-spring flood. A
side intake helps avoid the brunt of destrucƟve flood flows. The locaƟon of the intake also needs to be
at a point in the stream where there is a low seƩ lement build-up, a certain distance upstream from the
weir itself. For minimum debris, the intake should be located in the part of the stream where there is
the fastest current, such as on the outside radius of a bend, and off to the side of the natural creek bed,
as long as the flow is not too turbulent. The intake pipe, which is the beginning of the penstock, must
also be located at sufficient water depth to avoid freezing. The intake trashrack and screens should be
able to prevent fish from entering the penstock.
AVEC Cosmos Hills Hydropower Page 32 22 September 2010
Figure 22: Intake screens and pipe for the Black Bear Lake hydroelectric plant on Prince of Wales Island, Alaska
(photo courtesy of Alaska Power & Telephone Company)
Penstock
The penstock will consist of a pipe which carries water downhill from the intake to the powerhouse.
OpƟons for insulated pipe will be explored, and the cost esƟmates for Dahl and Cosmos Creeks in this
report include insulated penstocks for each site. Above-ground installaƟon is preferred because buried
penstock, even if it is insulated, would take too long to warm up in the spring due to cold ground
temperature. Figure 23 shows a buried penstock under construcƟon at the 1 00-kW McRoberts Creek
hydroelectric plant in 1990.
The assumed pipe head loss for the Cosmos, Dahl, Jade and Canyon sites is assumed to be 10%. The
proposed design flow/length of pipe. The penstock pipe inner-diameter chosen was deliberately over-
sized for the assumed design flow. The outer-diameter of the penstock pipe, or pipe wall thickness,
needs to increase further downhill, in order to handle increasing water pressure. Material choices for
the penstock pipe include high-density polyethylene (HDPE) plasƟc for low pressures, and steel for
higher pressure. At the end of the penstock, inside the powerhouse, a valve controls the amount of flow
reaching the turbine(s). When the plant needs to be shut down, this valve needs a slow-closing
blockage of water. Such surge pressures, while only temporary, can severely damage the penstock pipe
and other parts of the hydroelectric plant.
AVEC Cosmos Hills Hydropower Page 33 22 September 2010
Figure 23: Penstock under construcƟon for McRoberts Creek hydroelectric plant
(photo courtesy of Polarconsult Alaska, Inc.)
Tailrace
The tailrace conduit carries water out of the powerhouse and back into the stream, and needs to be
powerhouse.
Powerhouse
Permafrost may be encountered beneath the powerhouse, so the thermal regime of the permafrost
must be maintained to provide stability. A typical powerhouse for this scale of hydroelectric plant, of the
McRoberts Creek development near Palmer, is shown in Figure 24. The powerhouse in the photo is
constructed from concrete blocks. The type of powerhouse building for Cosmos Hills remains to be
determined, and will likely consist of some sort of prefabricated structure with ArcƟc insulaƟon.
Figure 24: Small concrete powerhouse structure for 100-kW McRoberts Creek hydroelectric plant.
(photo courtesy of Polarconsult Alaska, Inc.)
AVEC Cosmos Hills Hydropower Page 34 22 September 2010
Turbine and Generator
The most pracƟcal turbine type for the hydropower sites in the Kobuk Valley will vary from site to site
(shown in Table 13). Power generaƟon on the scale of 100 kW and above is generally done with a three-
phase, 60-Hz alternaƟng current (ac) synchronous generator. Connected to the generator inside the
powerhouse will be a load controller, and addiƟonal protecƟve and control equipment. A flywheel is
also used by many small-scale hydro generators to provide frequency stability. A typical micro-hydro
turbine and generator unit is shown in Figure 25. An asynchronous (inducƟon) generator could also be
used, which is generally less expensive than a synchronous generator of equal capacity. An inducƟon
generator is more easily synchronized with a local distribuƟon grid, though must be self-excited (with
capacitors) during a grid outage. The prices of all equipment packages in Table 13 are based on the use
of a synchronous generator and are water to wire powerhouse equipment package feasibility level
esƟmates. In addiƟon to the turbine types idenƟfied by Canyon Hydro in the table below, Turgo turbine
opƟons should be explored.
Table 13: Turbine-generator unit price quotes from Canyon Hydro (March 2010, not incl. shipping from SeaƩle)
Hydro site (configuraƟon) Turbine type # of units Unit capacity (kW) Cost per unit
Dahl Creek Crossflow 1 430 $250,000
Cosmos Creek VerƟcal Pelton 1 950 1,500,000
Jade Creek Horizontal Pelton 1 105 135,000
Canyon Creek Crossflow 1 150 164,000
Shungnak (full dam) Francis 2 6,800 3,000,000
Shungnak (limited dam) Francis 2 5,500 2,800,000
Shungnak (run-of-river) Francis 2 3,000 3,000,000
Kogoluktuk (full dam) Francis 2 6,100 3,800,000
Kogoluktuk (limited dam) Francis 2 3,600 3,800,000
Kogoluktuk (run-of-river) Kaplan 2 1,600 2,500,000
Figure 25: Turbine-generator set for 100-kW McRoberts Creek plant
(photo courtesy of Polarconsult Alaska, Inc.)
AVEC Cosmos Hills Hydropower Page 35 22 September 2010
Governing and Electronic Control Systems
The electronic control system should include an automaƟc shutdown for very low water periods or
emergencies such as a freeze-up or ice jam at the intake trashrack. A three-phase electronic load
electric heater inside the powerhouse.
Electric Power Transmission/Distribution
Power lines must be constructed to connect the hydroelectric plants to communiƟes. An exisƟng
7.2/12.4 kV power line connects Shungnak to Kobuk. Figure 26 shows the possible Cosmos Hills
hydroelectric site locaƟons and conceptual power line routes that would connect them to the
communiƟes of Ambler, Shungnak and Kobuk. The approximate route of the exisƟng Shungnak -Kobuk
line is shown in red. Table 14 shows the esƟmated costs of these conceptual power lines. Power lines
should be designed to anƟcipate future capacity increases (such as if addiƟonal hydropower plants are
built over Ɵme), as well as poles that could also accommodate communicaƟon lines between
communiƟes.
Figure 26: Possible hydroelectric sites and power line routes (map by Paula Hansen)
AVEC Cosmos Hills Hydropower Page 36 22 September 2010
Table 14: Power line cost esƟmates for Cosmos Hills projects (assumed installed cost of power lines: $400,000/mile)
Proposed power line EsƟmated length (miles) EsƟmated cost
Kogoluktuk River-Kobuk 8.5 $3,400,000
Dahl Creek-Kobuk 2 800,000
Cosmos Creek-Shungnak 7 2,800,000
Shungnak River-Cosmos Creek 4.5 1,800,000
Shungnak River-Ambler 18.5 7,400,000
Jade Creek East Fork-Ambler 9 3,600,000
Canyon Creek-Kiana 8.5 3,400,000
Access Roads and Other Infrastructure
Access roads to the hydroelectric plants may have to be improved or constructed. The Alaska
Department of TransportaƟon and Public FaciliƟes will soon be conducƟng planning, design and
engineering studies of new roads in the Ambler Mining District, including upgrades to the Kobuk-Bornite
road. Possible new roads connecƟng from the Cosmos Hills area to the proposed Western Access Road
(connecƟng from the Dalton Highway to Nome) will also be studied.
Operation and Maintenance Considerations
The operators of hydroelectric plants in the Cosmos Hills area should shut down the faciliƟes between
November and April, in a winter . During shutdown, the penstock should be drained
of water and the intake covered. -
penstock during cold temperatures, so adequate drains are needed in the penstock and powerhouse.
Some exisƟng small hydroelectric plants in cold regions are shut down during lowest-flow period of the
cold season.
Remote monitoring systems should be explored for hydroelectric plant operaƟons, similar to what
Alaska Energy Authority is doing now with diesel generaƟon plants in rural Alaska.
exisƟng diesel powerhouses in Shungnak and Ambler will have to be upgraded to accommodate
connecƟon to a new hydroelectric plant. Combined with new communicaƟons systems, this is esƟmated
to cost $150,000 per diesel powerhouse.
Ice Problems and Mitigation Measures
Frazil ice is likely to occur in the Kobuk during the shoulder season of late spring and
early fall. This type of ice consists of small parƟcles which form in turbulent or open water during
excepƟonally cold temperatures. Of parƟcular concern for the formaƟon of frazil are upstream cascades.
Frazil ice can sƟck to an intake trashrack, potenƟally blocking all flow into the power plant. Electrically -
heated intake trashrack bars help prevent ice from sƟcking could take a significant amount of power
AVEC Cosmos Hills Hydropower Page 37 22 September 2010
other types of ice may have to be mechanically cleared from the intake area during cold weather. AVEC
will study the possibility of operators regularly visiƟng the operaƟng hydroelectric plants during the
shoulder season, including a real-Ɵme camera on the intake area to monitor icing problems. It is
reasonable to expect that operators could travel by ATV or snowmachine from Shungnak or Kobuk to
aƩend to ice problems during the shoulder season, barring stormy weather.
Induced Ice Cover Formation
Surface ice cover formaƟon, upstream from the hydro plant intake, is the most effecƟve way to prevent
frazil ice problems. However, varying condiƟons at different hydroelectric plants may necessitate other
methods of managing frazil ice. An ice cover is by far the best protecƟon against frazil ice formaƟon due
to its insulaƟng properƟes. Water underneath a solid ice cover will remain above 0°C, and thus the cover
effecƟvely eliminates supercooling. Water velocity during the freeze-up period should be kept low.
Ideally, an ice cover should be created as early as possible during the cold season, before Ɵmes of peak
power demand.
An ice cover can even be induced earlier in the cold season than normal by a sheet ice retenƟon
structure form a floaƟng
surface-ice blockade to reduce water turbulence, can be a useful tool to induce ice cover formaƟon of
rivers with low velocity flow. Other methods of causing an ice cover to form include arrays of ropes or
nets to capture frazil ice parƟcles. However, the topography for a turbulent mountain stream such as
those in the Cosmos Hills limits the size of the pool at the plant intake. On a stream with steep gradient,
sheet ice retenƟon structures would only be pracƟcal in the pool created by the intake weir, which may
not be large enough to reduce frazil ice producƟon upstream.
Mechanical Ice Removal
Raking is the most widespread method of removing frazil ice once it has accumulated on a trashrack,
though requires cauƟon of not leƫ ng the raked ice get sucked into the penstock. Raking the intakes by
hand is the most common method, but other techniques include back flushing, which reverses
differenƟal pressure on a trashrack. The amount of water that needs to be used for flushing ice is
directly proporƟonate to the amount of ice that needs to be flushed. The flush -clearing process uses a
lot of water, which is usually scarce when ice problems are most severe for a run-of-river hydro plant.
Another possible technique of mechanical ice removal is using air bubbles, and is used on the intakes of
some large hydroelectric faciliƟes with reservoirs. It is uncertain how any of these mechanical ice-
removal techniques would work on small-scale, run-of-river sites like those in the Kobuk Valley.
Prevention of Ice Accumulation on Intake Trashrack
While energy-intensive, heaƟng can be an effecƟve method to prevent intake ice buildup, and is
commonly used at hydroelectric plants in cold regions. However, to be effecƟve, heaƟng must begin
before frazil ice starts forming in the river. Usually, trashrack heaƟng can only prevent ice parƟcles from
sƟcking to the metal bars of the intake structure, and is not capable of melƟng an accumulated mass of
ice. In principle, the metal bar surfaces only need to be slightly above freezing to prevent the ice from
sƟcking. Direct electric heaƟng of the intake trashrack is also a reliable method, and is a pracƟce nearly a
century old. The leading edge of the trashrack bars is the most important place for heaƟng. Electric
cable designed for heaƟng soil has also been used for this purpose. Another method used at some
AVEC Cosmos Hills Hydropower Page 38 22 September 2010
hydroelectric faciliƟes covering the area of the intake structure by a heated roof to stop heat loss from
the water, and also to prevent snow buildup on the structure.
Power requirements for electric trashrack heaƟng, in terms of power per volume of water flow, are
between 5 and 10 kW per m3/sec. Hydroelectric plants in the Cosmos Hills should be able to spare up
this amount of power to heat up the trashrack if it is needed keep the system going. However, these
power requirements are only necessary when the water flowing through the trashrack is supercooled.
An electronic thermo-sensor at the intake could be used to detect when the water flowing into the
intake is supercooled, so that the electric heaƟng circuit is only acƟvated when needed. A greater
challenge would be the cost of providing a power cable up the length of the penstock pipe to provide
electricity to the intake heaƟng system, as no power generaƟon would occur at the intake site itself.
Perhaps some other heat source could be delivered to the intake area if needed in an emergency, such
as heaƟng oil.
Certain trashrack coaƟngs and materials such as HDPE also help prevent ice from sƟcking. On the
Tazimina Hydroelectric Plant near Lake Clark, Alaska, trashracks made from HDPE plasƟc were used to
reduce frazil ice accumulaƟon. In addiƟon, electric heat-trace placed in the concrete walls of the intake
box, designed to be used in case of plant shutdown.
Penstock Icing
When the hydroelectric plant is operaƟng in air temperatures well below freezing, there is an inherent
risk in taking water j (and ice) at the intake - of above
ground penstock. Significant heat loss can occur from the water through the pipe if it is not insulated,
leading to icing at perimeter & eventual closing of line with ice. Insulated pipe is necessary to help
prevent and miƟgate penstock icing problems possible during cold nights in late spring and early
autumn.
Frozen Ground Issues
For micro-scale hydroelectric plants in cold regions, penstock ice problems are rare compared to those
which happen at the intake. However, any hydroelectric penstock can freeze if it is leŌ dewatered or
quiescent for extended periods of low temperatures. Such extreme circumstances need to be prepared
for in order to protect the microhydro plant from ice damage. The risks of construcƟon on permafrost,
or frozen bedrock (which may contain ice lenses between the rock strata) also need to be explored.
However, the cost esƟmates in this report assumes no special ArcƟc foundaƟon for the powerhouse and
other infrastructure because of the strong possibility they will be built atop a gravel foundaƟon, and not
permafrost soil.
AVEC Cosmos Hills Hydropower Page 39 22 September 2010
4.Preliminary Project Cost Estimates
Preliminary installed cost esƟmates are summarized in Table 15. The costs shown for the Shungnak and
Kogoluktuk sites are from the 2006 mine energy study by Shaw, Stone & Webster. The Dahl and Cosmos
esƟmates were provided in April 2010 by Chuck Clark and Erhling Young, PE, of NANA WorleyParsons
(see Appendix D), and the Wesley Creek cost esƟmate is based on the Dahl Creek site.
Table 15: PotenƟal costs of Upper Kobuk hydroelectric concepts
Site Hydroelectric
Plant
ConfiguraƟon
Installed
capacity,
kW
EsƟmated
capital
installaƟon cost,
million $
EsƟmated capital cost
per kW capacity
installed, $
Dahl Creek Run-of-river 430 10.3 24,000
Wesley Creek Run-of-river 480 13.0 27,080
Cosmos Creek Run-of-river 950 25.3 26,600
Shungnak River
Storage dam,
full-sized 13,000 83.7 6,900
Storage dam,
reduced-sized 10,600 62 5,850
Run-of-river 5,800 58 10,000
Kogoluktuk River
Storage dam,
full-sized 11,700 158.2 13,500
Storage dam,
reduced-sized 7,000 80 11,400
Run-of-river 3,200 32 10,000
AVEC Cosmos Hills Hydropower Page 40 22 September 2010
5.Economic Analysis
The esƟmated cost of energy generated by the proposed Dahl Creek, Wesley Creek and Cosmos Creek
hydroelectric projects appears to be compeƟƟve with diesel generaƟon. However, these esƟmates are
only preliminary, and more detail designs and cost esƟmates must be completed for a more accurate
analysis. Table 16 shows the results of a simplified cost-of-electricity calculaƟon done using the HOMER
soŌware. The full results on the HOMER program models for Dahl and Cosmos sites are shown in
Appendix F.
AssumpƟons used in HOMER model:
50 year plant life/loan term
6% interest rate
No inflaƟon
Power line losses not included
Table 16: Preliminary Results of HOMER economic model for Dahl and Cosmos hydropower sites
Project Dahl Creek Cosmos Creek
EsƟmated installed cost $10,300,000 $25,300,000
EsƟmated annual O&M cost $100,000 $200,000
Nominal capacity 430 kW 952 kW
Average output 205 kW 418 kW
Capacity factor 48%44%
Annual electricity demand 1,522,417 kWh
(Shungnak & Kobuk)
2,883,511 kWh
(Ambler, Shungnak & Kobuk)
Total annual hydroelectric
energy producƟon
(May-October only)
1,741,048 kWh 3,660,523 kWh
Total annual excess energy
(May-October only)
1,064,338 kWh 2,378,784 kWh
GeneraƟon cost of hydropower $0.43/kWh $0.49/kWh
For the 480-kW, $13 million Wesley Creek site, assuming an annual energy producƟon of 2,200,000
kWh, the esƟmated generaƟon cost of hydropower is $0.44/kWh. This cost is based on the HOMER
model for the similar Dahl Creek site, taking into account the small differences in installaƟon cost and
annual energy output.
-only generaƟon cost of
$0.34/kWh, the esƟmated cost of hydroelectric-generated electricity at Dahl Creek and Wesley Creek
appears compeƟƟve with a diesel fuel cost of $5.50/gallon, and Cosmos Creek appears compeƟƟve with
a diesel fuel cost of $6.30/gallon. These are the fuel prices that HOMER predicts will result in equivalent
diesel/hydro generaƟon costs for each plant opƟon. It is worth noƟng that the cost of hydropower
generated will be fixed, while the cost of diesel-generated electricity is unpredictable, and is generally
expected to increase in the years ahead.
AVEC Cosmos Hills Hydropower Page 41 22 September 2010
6.Land Ownership
Most of the potenƟal Cosmos Hills hydropower sites are located on NANA property. NANA is commiƩed
to this project and will provide the required land-use permits for AVEC. The Cosmos, Wesley, Dahl and
Canyon sites are located on NANA land. The Kogoluktuk River, Shungnak River, and Jade Creek
hydropower sites may be at least parƟally located on federal (BLM) land. The land ownership map in
Figure 27 and Figure 28 shows the locaƟon of the various potenƟal hydropower sites in t he Kobuk
Valley.
With the probability that barging in materials for construcƟon and operaƟons along the Kobuk River,
addiƟonal coordinaƟon with the NaƟonal Parks Service and U.S. Fish and Wildlife Service may be
required as transport will be conducted through federal parkland (Kobuk Valley NaƟonal Park, Selawik
NaƟonal Wildlife Refuge).
Figure 27: Land ownership of possible hydroelectric sites and power line routes, with the Cosmos and Dahl sites labeled (map
by Paula Hansen)
AVEC Cosmos Hills Hydropower Page 42 22 September 2010
Figure 28: Land ownership of possible hydroelectric sites and power line routes, closer view of Cosmos Hills area
(map by Paula Hansen)
AVEC Cosmos Hills Hydropower Page 43 22 September 2010
7.Environmental Requirements
Environmental Permits
As required by various federal, state, and local laws, hydroelectric projects, including the in-water
components and associated roads and power lines, must acquire specific permits and approvals before
iniƟaƟng construcƟon. Based on preliminary work, it is expected that the following permi ts would be
needed: (A detailed list of required environmental permits will be developed as the project moves
forward.)
Federal Approvals
U.S. Army Corps of Engineers (USACE) SecƟon 404 Permit for work within waters of the U.S.,
including wetlands and SecƟon 10 permit for work within navigable waters
NaƟonal Oceanic and Atmospheric AdministraƟon (NOAA) Fisheries EssenƟal Fish Habitat
ConsultaƟon (if EssenƟal Fish Habitat would be impacted)
U.S. Fish and Wildlife Service (USFWS) SecƟon 7 (Endangered Species Act) ConsultaƟon
USFWS Bald Eagle NesƟng Tree CoordinaƟon
USFWS Migratory Bird ProtecƟon
State Approvals
Alaska Department of Environmental ConservaƟon (ADEC) Water CerƟficate of Reasonable
Assurance
Alaska Department of Fish and Game (ADF&G) Title 16 Fish Habitat Permit (for anadromous and
resident fish streams)
Alaska Department of Natural Resource (ADNR) Division of Coastal and Ocean Management
(DCOM) Coastal Zone Enforceable Policies Consistency DeterminaƟon (a porƟon of Cosmos Hills
is
ADNR ApplicaƟon for Water Rights
ADNR State Historic PreservaƟon Officer SecƟon 106 (of the NaƟonal Historic PreservaƟon Act)
Review
Local Approvals
Northwest ArcƟc Borough Title 9 Land Use Permit
FERC Licensing Requirements
In addiƟon to the environmental permits listed above, it is possible that some of the proposed Cosmos
Hills hydroelectric projects may fall under the jurisdicƟon of the Federal Energy Regulatory Commission
(FERC) under the Federal Power Act.
In 2009, AVEC secured separate Preliminary Permits from the FERC for developing hydroelectric projects
AVEC Cosmos Hills Hydropower Page 44 22 September 2010
the Shungnak and Kogoluktuk Rivers was asserted by NOAA that Pacific salmon
would be impacted. To maintain these permits and obtain approval for construcƟon and operaƟon of
hydroelectric faciliƟes on the Shungnak and Kogoluktuk Rivers, AVEC is required to complete the
following tasks under the integrated licensing process:
File a NoƟce of Intent/Preliminary ApplicaƟon Document
Complete Scoping AcƟviƟes
DraŌ and revise a Proposed Study Plan (PSP) and complete fieldwork following the PSP
DraŌ a Preliminary Licensing Proposal or DraŌ License ApplicaƟon
File a License ApplicaƟon
FERC Licensing Exemptions
Small hydropower projects, which are 5 megawaƩ s (MW) or less, that uƟlize a natural water feature for
head, may be exempt from the FERC licensing process. However, if a hydroelectric project impacts
required. Although addiƟonal informaƟon, especially related to salmon use, must be gathered for
confirmaƟon, it is expected that the following Cosmos Hills Hydroelectric Projects could fall under a
FERC exempƟon from licensing:
Jade Creek near Ambler
Cosmos Creek near Shungnak
Dahl Creek near Kobuk
Canyon Creek near Kiana
As specified in the exisƟng preliminary permits, the Kogoluktuk and Shungnak River Hydroelectric
projects would not be exempt as currently proposed; however, smaller projects on these rivers could be
exempt, depending on the proposal and depending on whether it is determined that essenƟal fish
habitat under the NOAA Fisheries jurisdicƟon could be impacted.
The exempƟon process is similar to the FERC licensing process, including the pre -filing process,
summarized above. The applicaƟon for exempƟon should include the following:
General InformaƟon
IniƟal Statement
Exhibit A (Project descripƟon and proposed operaƟng mode)
Exhibit E (Form and contents of an environmental assessment)
Exhibit F (General drawings)
Exhibit G (In GIS, project boundary and maps)
As summarized above, exempƟons from licensing are subject to mandatory terms and condiƟons from
the USFWS, NOAA Fisheries, ADNR, ADF&G, and other regulatory agencies.
FERC may revoke an exempƟon if construcƟon of a hydroelectric project has not begun within two years
or has not been completed within four years from the date on which the exempƟon was granted.
AVEC Cosmos Hills Hydropower Page 45 22 September 2010
Summer 2010 Environmental Studies
Anadromous Stream Mapper and the USFWS NaƟonal Wetland Inventory (NWI), the following
environmental studies are recommended for this phase of work:
Office-Based Wetlands DelineaƟon
Fisheries and AquaƟc Resources Study
Office-Based Cultural Resources Study
In general, based on preliminary projects plans, the study area could include:
A 2.2-mile-long reach within Dahl Creek
A 4.0-mile-long reach within Wesley Creek
A 3.8-mile-long reach within Cosmos Creek
Based on conversaƟons with FERC representaƟves and experts, field studies can be conducted o n a
potenƟal hydroelectric project without a FERC-approved Proposed Study Plan in place; however, the
project would risk having to repeat the work if the study methodology is not approved by resource
agencies. For this reason, an agency meeƟng to discuss the project and potenƟal fieldwork and
fieldwork methodology is recommended prior to iniƟaƟng any fieldwork.
Ofϐice-Based Wetlands Delineation
An office-based wetlands delineaƟon with a minimal field check is recommended for the Cosmos Hills
Hydroelectric Project to determine where areas of wetlands occur. The work would consist of using
Geographic InformaƟon Systems (GIS) mapping to delineate wetland areas in the office. A short field
reconnaissance would be conducted to determine wetland types. A complete and intense field
delineaƟon is not recommended unƟl a final project is selected and preliminary engineering is
completed.
Fisheries and Aquatic Resources Study
A study of fisheries and stream and river habitat is recommended to determine whether and what fish
species could be impacted by the possible Cosmos Hills Hydroelectric Project. Visual surveys, fish traps,
and electroshocking could be used to complete surveys within areas that could be impacted by
proposed hydroelectric faciliƟes; however, it is recommended that the methods for study of these
streams be developed together with ADF&G, NOAA Fisheries, USFWS and other interested agencies.
Ofϐice-Based Cultural Resources Study
An office study of cultural and historical features is recommended to iniƟate the idenƟficaƟon and
evaluaƟon of archaeological and historical resources within the hydroelectric project area of potenƟal
effect. All perƟnent archeological and historical literature and the records of the Alaska Heritage
Resources Survey will be reviewed to compile informaƟon. The work would focus on any known
buildings, structures, and objects in the APE that are listed in or otherwise eligible for the NaƟonal
Register of Historic Places.
AVEC Cosmos Hills Hydropower Page 46 22 September 2010
8.Public Outreach
Public meeƟngs on the Cosmos Hills hydropower studies were held in Ambler and Shungnak on March
24, 2010, and in Kobuk on March 25, 2010 (Figure 29, Figure 30 and Figure 31). The main purpose of the
meeƟngs was to inform community members about both the Upper Kobuk River Valley Biomass Study
and the Cosmos Hills Hydroelectric Feasibility Study projects. The other purposes for the meeƟngs were
to begin gathering local knowledge about the study areas, to answer quesƟons, and to hear any
concerns that community members may have about the projects. An informaƟonal pamphlet was
created, and distributed during the public meeƟngs.The pamphlet and minutes are given in Appendix B.
Each meeƟng followed the same agenda. Elia Sakeagak began each meeƟng by inviƟng a local elder to
open with a prayer, which she followed with introducƟons of the project team members. Next, Bill Wall
gave his presentaƟon on the Upper Kobuk River Valley Biomass project, follow
presentaƟon on the Cosmos Hills Hydroelectric Feasibility Study. Each presentaƟon was followed by a
quesƟon and answer period. Toward the end of each meeƟng the team invited community members up
to the presentaƟon tables where maps depicƟng study areas were laid out. There community members
pointed out subsistence use areas, animal migraƟon routes, dominant wind direcƟons, and other
miscellaneous pieces of informaƟon. Generally, residents of each village expressed the following
comments:
General posiƟve interest in the hydroelectric proposals
LocaƟons of fish and wildlife habitat
QuesƟons about the type of penstock pipe (length, diameter, material type, etc.)
QuesƟons about the number and locaƟon of hydroelectric plants that would be developed, and
communiƟes that would be served
QuesƟons about dams that were proposed in the past for the Shungnak and Kogoluktuk rivers
Figure 29:Public meeƟng in Ambler, March 24, 2010 (photo by Elia Sakeagak)
AVEC Cosmos Hills Hydropower Page 47 22 September 2010
Figure 30: Public meeƟng in Shungnak, March 24, 2010 (photo by Elia Sakeagak)
Figure 31: Public meeƟng in Kobuk, 25 March 2010 (photo by Eva Harvey)
AVEC Cosmos Hills Hydropower Page 48 22 September 2010
9.Conclusions and Recommendations
The Cosmos Hills-area hydropower sites of Dahl Creek, Wesley Creek, Cosmos Creek and Kogoluktuk
River appear to be aƩ racƟve economically and environmentally to develop, and are recommended for
further study. With esƟmated capaciƟes ranging between 430 kW and 3,200 kW, these three sites are
the most appropriately scaled for the energy needs of Shungnak, Kobuk and Ambler, and are located
relaƟvely close to exisƟng road and power line infrastructure. The three other potenƟal run-of-river
hydroelectric sites evaluated (Shungnak River, Jade Creek-East Fork near Ambler, and Canyon Creek near
Kiana), have been excluded from further consideraƟon because the expected installaƟon cost is too high
compared to the expected energy generated.
Dahl Creek:
The Dahl Creek site, with an esƟmated 430 kW of installed capacity, is recommended for further study
due to its projected energy output, and relaƟve proximity to electric load/exisƟng infrastructure. The
installaƟon cost of the 430-kW Dahl Creek project is esƟmated to be $10.3 million in 2010 dollars
(including 2 miles of new power line to connect to the exisƟng Shungnak-Kobuk power line). During the
summer 2010 field season, a new stream gauge will be installed on Dahl Creek, the aerial photography
and LIDAR mapping will be done of the proposed project area, studies will be conducted on wetlands
and fisheries habitat, and geotechnical condiƟons/hazards.
Wesley Creek:
The Wesley Creek site, with an esƟmated 480 kW of installed capacity, is recommended for further
study due to its projected energy output, and relaƟve proximity to electric load/exisƟng infrastructure.
The installaƟon cost of the 480-kW Wesley Creek project is esƟmated to be $13 million in 2010 dollars
(including 1.7 miles of new power line to connect to the exisƟng Shungnak-Kobuk power line). During
the summer 2010 field season, a new stream gauge will be installed on Wesley Creek, the aerial
photography and LIDAR mapping will be done of the proposed project area, studies will be conducted on
wetlands and fisheries habitat, and geotechnical condiƟons/hazards.
Cosmos Creek:
The Cosmos Creek site, with an esƟmated 950 kW of installed capacity , is recommended for further
study due to its projected energy output, and relaƟve proximity to electric load/exisƟng infrastructure.
The installaƟon cost of the 950-kW Cosmos Creek project is esƟmated to be $25.3 million in 2010 dollars
(including over 30 miles of new power line to connect the site to Shungnak and Ambler). During the
summer 2010 field season, a new stream gauge will be installed on Cosmos Creek, the aerial
photography and LIDAR mapping will be done of the proposed project area, studies will be conducted on
wetlands and fisheries habitat, and geotechnical condiƟons/hazards.
Kogoluktuk River:
The Kogoluktuk River run-of-river site, with an esƟmated installed capacity of up to 3.2 MW, is
recommended for further study due to its projected energy output, and potenƟal ability to produce
hydropower for more than half the year. The installaƟon cost of a 3.2 MW Kogolukutuk River run-of-
river project is esƟmated to be $32 million in 2010 dollars (not including the new access road and power
AVEC Cosmos Hills Hydropower Page 49 22 September 2010
line). During the summer 2010 field season, a new stream gauge will be installed on the Kogoluktuk
River, and the aerial photography and LIDAR mapping will be done of the proposed project area.
Shungnak River:
The Shungnak River run-of-river hydropower site, with an esƟmated 5.8 M W of installed capacity, is not
recommended for further study because of its limited accessibility, and greater distance to a community
electric load compared to the four other hydropower sites near Shungnak and Kobuk. The installaƟon
cost of a 5.8 MW Shungnak River run-of-river project is esƟmated to be $58 million in 2010 dollars (not
including the new access road and power line). The Shungnak River also has a smaller watershed, and
thus less expected year-round flow, compared to the Kogoluktuk River.
Jade Creek - East Fork:
The Jade Creek-East Fork hydropower site, with an esƟmated 105 kW of installed capacity, is not
recommended for further study because of its small esƟmated generaƟon capacity, limited accessibility,
and relaƟvely long distance to a community electric load.
Canyon Creek (Kiana):
The Canyon Creek hydropower site, with an esƟmated 150 kW of installed capacity, is not
recommended for further study because of its small esƟmated generaƟon capacity, limited accessibility,
and relaƟvely long distance to a community electric load.
AVEC Cosmos Hills Hydropower Page 50 22 September 2010
10. References
NANA Region Strategic Energy Plan. Prepared by NANA Pacific for NANA Regional CorporaƟon,
December 2008.
Cold Climate Problems of a Micro-Hydroelectric Development on Crow Creek, Alaska. Brian Yanity.
Masters thesis, University of Alaska Anchorage, School of Engineering, December 2007.
Crimp, Steve Colt, and Mark A. Foster. Presented at ArcƟc Energy Summit, Anchorage, October 2007.
Mine Power Study: ArcƟc Project Ambler Mining District Alaska. Shaw Stone & Webster Management
Consultants, Inc., February 2006.
Rural Hydroelectric Assessment and Development Study, Phase 1 Report. Prepared by Locher Interests
Ltd. for Alaska Department of Community and Regional Affairs, Division of Energy, Anchorage, 1997.
Reconnaissance of Surface-Water Resources in the Kobuk River Basin, Alaska, 1979-80. Joseph M.
Childers and Donald R. Kernodle, US Geological Survey, Water-Resources InvesƟgaƟons Report, 1983.
Regional Inventory and Reconnaissance Study for Small Hydropower Projects: Northwest Alaska. OƩ
Water Engineers, Inc., prepared for the U.S. Army Corps of Engineers, Alaska District, May 1981.
Small Hydroelectric Inventory of Villages Served by Alaska Village Electric CooperaƟve, U.S. Dept. of
Energy, Alaska Power AdministraƟon, December 1979.