Alcatraz Prison Goes Solar

Solar panels on the Cellhouse roof at Alcatraz | Photo: National Park Service

The National Renewable Energy Laboratory (NREL) is reporting that one of San Francisco's most notorious tourist attractions has gone solar. Alcatraz Island, a forbidding outcrop in the middle of San Francisco Bay that was used as a prison from 1861-1963, now gets most of its electrical power from solar panels.

Now a unit of the National Park Service (NPS), the island has been kept off the mainland power grid due to the mile and a half of water between it and San Francisco. Until recently, any electrical power on the island was provided by diesel generators. But now due to a partnership between NREL and NPS, 1,300 solar panels provide 60% of the island's power.

The islands solar panels, which occupy the roof of the historic Cellhouse building, feed power to a bank of batteries in the prison's basement. With 2,000 amp-hours of storage capacity, the batteries help maintain solar power to the island's mini-grid even when one of San Francisco's trademarked summer fogs rolls in.

The project has actually been in the works since 1995, when NPS asked NREL to conduct feasibility studies on the park unit's solar potential. Historic preservation concerns proved an obstacle that had to be overcome: the Cellhouse building and the so-called New Industries Building -- the prison workhouse -- are historic landmarks, and a protection group objected to solar panels on the workhouse roof that were visible to tourists. A deal with the Sacramento Municipal Utility District (SMUD) fell through after the Park Service couldn't guarantee completion of a project given lingering historic preservation concerns.

But with those concerns assuaged by less-visible panels atop the Cellhouse, the project was restarted in 2010 with $3.6 million in American Reinvestment and Recovery Act funding. 307 kilowatts of photovoltaic capacity now pumps about 400,000 kilowatt-hours into Alcatraz's wires a year, significantly cutting down the amount of diesel exhaust the island emits into the Bay Area's already overburdened airshed.

It's an urban PV success story, and if it can happen in one of the foggiest places in California it can happen anywhere.

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