Friday, August 24, 2012

Solar Cells Light Up Prison Cells on 'The Rock'

Alcatraz Island in San Francisco Bay is referred to as "The Rock" and was home to a notorious prison for 75 years. National Renewable Energy Research Laboratory (NREL) recently helped the National Park Service and the DOE Federal Energy Management Program transform the island's electricity source from diesel fuel to photovoltaic panels on the rooftop of the Cellhouse Building

"Machine Gun Kelly," Al Capone, the "Birdman" — Alcatraz prison has had some infamous residents.

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.
This photo shows several rows of tilted solar panels in the foreground, with the blue waters of the San Francisco Bay and the leafy forest of the California mainland in the background.
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 consumption.

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.... 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) at NREL. 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.

NREL's involvement began in 1995, when FEMP enlisted NREL's Applying Technologies team to monitor the strength of the sun at the island, do a feasibility study, and mock up what a solar installation would look like from up close and from across the bay.

FEMP and the NPS contracted with the Sacramento Municipal Utility District (SMUD) to install PV on Alcatraz's New Industries Building and sell power to NPS for a penny less per kilowatt-hour than what it was costing for diesel electricity.

SMUD got as far as putting a new roof on Alcatraz's New Industries Building and installing roof stanchions to hold the solar panels.

But a historic landmark group protested that the solar panels would be too visible. They could be seen by tourists from an exit door in the exercise yard — and that would mar the historic nature of the New Industries Building, where Al Capone once worked a sewing machine, and Machine Gun Kelly did the laundry.

The Cellhouse became a possible alternative because its roof was less visible from the ground or from the bay.

National Renewable Energy Laboratory (NREL)
July 23, 2012

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