HomeMy WebLinkAboutHydro Review Article_Replacing Diesel Fuel with Hydroelectric Generation Sep 2002HYDRO*
REVIEW
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North Axterica,i HydrotTe�etric Industry
VoL XXI, No. 5, September 2002
Technologies for Tagging Fish
Taking a Closer Look at tarn Safety
Replacing Diesel Fuel
With Hydroelectric Generation
By using its new renewable energy source, the 6-MW Power
Creek Hydro Project, the Cordova Electric Cooperative will
reduce consumption of I million gallons of diesel fuel, improve
air quality, reduce consumer power costs, and benefit
businesses in this remote Alaskan community.
By Kenneth J. Gates and
Thom A. Fischer
overed with stands of spruce and
hemlock, the Chugach Moun-
tains in south-central Alaska
tower above the city of Cordova. At just
30 feet above sea level, the city is acces-
sible only by air or sea. It is bound on
the south by the Gulf of Alaska, on the
west by Prince William Sound, on the
north by 6,000-foot glacial mountains,
and on the east by the vast estuary of the
Copper River Delta. This area is home
to an abundant population of Sitka
blackmail deer, moose, and brown and
black bears.
With a year-round population of
2,600 and a summer census of about
5,000, Cordova's principal industry is
fishing and fish processing. It's a pris-
tine spot noted for salmon and halibut
fishing, as well as big game and water-
fowl hunting. The city also serves as a
base for hiking the scenic wilderness
and for viewing the annual migration of
more than 20 million waterfowl and
shore birds through the Copper River
Ken Gates is CEO and general manager
of Cordova Electric Cooperative, Inc.,
owner of the 6-MW Power Creek Hydro
Project. Thom Fischer is president of
the Whitewater Engineering Corpora-
tion, whic4 designed and constructed
Power Creek.
Delta. It also is noteworthy that the area
is prone to avalanches and earthquake
activity.
These environmental and structural
factors figured into the design of the 6-
MW Power Creek Hydro Project, which
began commercial operation January 1,
2002.
The 1,680 residences and businesses
that make up the 49-square-mile ser-
vice area of the Cordova Electric Co-
operative historically have relied on
diesel fuel for the generation of elec-
tricity. But, in the early 1990s, a com-
bination of unstable fuel prices and air
quality considerations made construc-
tion of a hydro plant on Power Creek
attractive.
With an average streamflow of 255
cubic feet per second (cfs), glacier -fed
Power Creek provides a consistent, reli-
able volume of water year-round. Pri-
vate developers and government agen-
cies have been interested in the site for a
bydro project for nearly 100 years.
However, geographic challenges to
building a dam at the site discouraged
development.
In the mid 1980s, Cordova Electric's
board of directors expressed interest in
pursuing two hydro projects —one at
Humpback Creek, 7 miles north of Cor-
dova, and one at Power Creek, 7 miles
east. The board hoped that, in addition
to stabilizing costs and reducing emis-
sions, the project would help retain and
expand existing area businesses, pro-
mote economic development, provide
lower costs for residential users, and
take advantage of a renewable resource.
The board tackled the 1.25-MW
Humpback Creek project first.' After its
completion in 1991, Whitewater Engi-
neering Corporation, which had worked
with Cordova Electric on the Humpback
project, saw an opportunity to build a
run -of -the -river project rather than a
storage project —on Power Creek.
Whitewater filed for a Federal Energy
Regulatory Commission (FERC) prelim-
inary permit as an independent power
producer. Despite the fact that The Eyak
Corporation, a local native corporation
that owned the underlying land, chal-
lenged the application, FERC issued the
preliminary permit to Whitewater in
1992.
Four years later, Whitewater, Cordova
Electric, and The Eyak Corporation
agreed that the way to deliver the least
expensive energy to ratepayers was for
Cordova Electric to own and operate the
project under the following terms:
— Cordova Electric would enter into
a 50-year lease with The Eyak Corpora-
tion for the 25 acres of land the project
required;
— The Eyak Corporation would
assist in obtaining federal grants; and
— Whitewater would design and con-
struct the facility.
In 1997, Cordova Electric contracted
with Whitewater to construct the proj-
ect, and Whitewater transferred the
FERC license to the cooperative. Con-
struction began in October 1998.
Design Considerations
When developers considered the site for
a hydro plant as early as 1908, their
plans called for a traditional project with
a dam and water storage reservoir. How-
ever, engineers and geologists ques-
tioned whether the local geology would
support such a structure because of the
inability to reach bedrock. In addition,
Power Creek floods in excess of 6,000
34 HYDRO REVIEW / SEPTEMBER 2002
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,k
Minimizing Risk
To minimize the risk of avalanche damage
to the penstock, the first 2,600 feet of the
welded steel, epoxy -lined pipe is buried.
The remaining section runs through the
Chugach Mountains via a 9-foot-diameter
tunnel, then continues to the powerhouse.
requests are approved, Cordova Electric
can lower its project debt and pass along
savings realized from reduced debt ser-
vice to its customers.
Since operations began, hydro gener-
ation has met 25 percent of winter
demand, with diesel -fuel generation
providing the rest. During the spring,
summer, and fall months, the hydro
plant is expected to meet 100 percent of
demand for electricity. On an annual
basis, the cooperative expects that hydro
generation will meet about 75 percent of
overall demand.
Operations of the hydro plant have
led to a 4-cent-per-kilowatt-hour drop
in diesel surcharges users now pay. Pro-
jections show an expected annual re-
duction of 1 million gallons of diesel
fuel. Part of the savings, however, will
be offset by debt service requirements.
Nonetheless, consumers will benefit not
only from lower and stable electricity
prices, but also from clean, emissions -
free generation. ■
Mr. Gates rnav be contacted at the
Cordova Electric Cooperative, Inc.,
705 Second Street, P.O. Box 20, Cor-
dova, AID 99574; (907) 424-5555; Fax:
(907) 424-5527, E-mail: legates@
cordovaelectric.com. Mr. Fischer may
be contacted at Whitewater Engineer-
ing Corporation, 625 Cornwall Avenue,
Bellingham, WA 98225; (360) 738-
9999, extension 111; E-mail: thom @
whrtewatereng. cold.
Note:
'Smith-Noggle, Laura, "Humpback
Creek Supplies Power To Alaskan
Village," Hydro Review, Volume XI,
No. 6, October 1992, pages 36-40.
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