POWER December 2015 - 26

TOP PLANTS
Blue Lake Expansion Project,
Sitka, Alaska
Owner/operator: City and Borough of Sitka
Courtesy: Desiree Brandis/City and Borough of Sitka
When you live on an island in a relatively isolated location with no connection to a
mainland power grid, having a reliable source of electricity is important. The Blue
Lake Expansion Project provides exactly that for Sitka, allowing hydropower to supply
100% of the town's needs.:
Aaron Larson
B
aranof Island is home to Sitka, Alaska.
Located on the outer coast of Alaska's
Inside Passage, it is accessible only
by air and sea (although once on the island,
standard forms of transportation are common).
Due to its relatively isolated location,
the island is not connected to a larger electric
power grid, which means the City and Borough
of Sitka must operate its own electrical
system and plan for changes in load.
It might surprise readers to learn that Sitka's
climate is extremely mild for its latitude,
on the 57th parallel north. The lowest recorded
temperature is -1F, logged in February 1948.
However, with its oceanic climate, the area
receives abundant rainfall. The average annual
precipitation in Sitka is 131.74 inches,
more than three times the amount received in
Seattle, Wash., which is considered one of the
rainiest cities in the U.S. In fact, some form
of precipitation is documented in Sitka during
two out of every three days on average.
26
The Oil-Electricity Link
The City and Borough of Sitka owns and operates
two hydroelectric projects, which generate
electricity for the area. The Blue Lake
Project was originally licensed in March 1958,
while the Green Lake Project was added 21
years later. In 2002, Sitka began the process
of relicensing the Blue Lake Project. At the
time, fuel oil prices in Sitka were low ($0.71
per gallon) and electricity demand growth
was predicted to be less than 1% annually. In
other words, the Blue Lake Project seemed adequately
sized to accommodate future needs.
However, from 2002 through 2008, the
price of fuel oil rose steadily, to $3.24 per
gallon. That increase led many residents and
businesses in Sitka to switch from fuel oil to
electric heating systems. Although the heating
changes played a large role in electricity
demand growth, the local seafood processing
industry also saw unexpected growth. In 2006
alone, the city experienced a 7% load increase,
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followed by 5% the next year. Those two years
of increases consumed 12 years of expected
cushion. Something needed to be done.
The city conducted feasibility studies to
determine how best to meet demand. It evaluated
hydro, diesel, wind, tidal, and geothermal
energy. Based on the results, hydroelectric
generation was considered the best alternative.
Expansion of the Blue Lake Project made
more sense than expanding the Green Lake
Project or developing an entirely new project.
The Blue Lake Project had more water inflow
than the existing turbines could use, and the
dam was built in a canyon that could geotechnically
support a significantly higher dam.
" Building the dam is the easiest part, " said
Dean Orbison, project manager for the City
and Borough of Sitka. " It's getting permission
that's the hardest. "
Sitka filed a notification of intent to apply for
a capacity-related amendment to the Blue Lake
Project license with the Federal Energy RegulaPOWER
| December 2015
http://www.powermag.com
POWER December 2015

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