San Francisco, July 23, 2012 - "Machine Gun
Kelly," Al Capone, the "Birdman" - Alcatraz prison has had some
infamous residents on the craggy island known as "The Rock" in the
middle of San Francisco Bay.
Now, the prison is host to 1,300 solar panels, powering lights
and appliances that for three-quarters of a century were powered by
diesel fuel ferried across the bay.
The panels are part of an effort by the National Park
Service (NPS) and the U.S. Department of Energy's (DOE)
National Renewable Energy Laboratory (NREL) to bring clean energy
to national parks and landmarks.
Blackberries and honeysuckles still grace Alcatraz Island, and
black-crowned night herons and slender salamanders still circle
above and below. But diesel fuel use has been slashed, and that
means far less corrosion of pipes and smokestacks, and less
pollution in the bay.
Instead, a 307-kilowatt photovoltaic (PV) array sits on the roof
of the main Cellhouse building, attached to two 2,000-amp-hour
battery strings and an inverter plant.
The new 1,300-panel system produces close to 400,000
kilowatt-hours of electricity a year, reducing carbon dioxide (CO2)
emissions by about 337,000 kilograms a year and reducing the time
the generator runs from 100% to 40%.
The NPS also made some energy efficiency changes, such as better
light bulbs and changes in operation to reduce energy
A massive solar battery system helps power the island when the
sun doesn't shine - and it, too, is hidden from the view of the 1.4
million visitors the island and prison get each year.
The $3.6 million project was funded by the American Reinvestment
and Recovery Act - and, importantly, it is saving money. The cost
of transporting diesel fuel to the island (maintenance costs and
the price of the fuel itself) boosted the cost of electricity for
the island to about 76 cents a kilowatt-hour, said Andy Walker, a
senior engineer and task leader for design assistance in the
DOE Federal Energy Management Program (FEMP)
The PV project brings that cost to 71 cents a kilowatt-hour, and
that includes the capital costs of buying the solar panels and
erecting them on roofs.
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