Alcatraz Island in the San Francisco Bay, known for years as “The Rock”, spent 30 years as a high-security federal prison with a tough reputation. Now a National Historic Landmark and part of the National Park system, Alcatraz falls under President Obama’s mandate for federal agencies to greatly reduce greenhouse gas emissions (30 percent by 2020).
For years, Alcatraz has generated electricity by running two diesel generators, at a cost of $700,000 a year on fuel. But a couple of years ago, a plan was formulated to install solar capable of generating enough energy to power the island.
Installation couldn’t have come at a better time since solar panel prices are lower than ever before and diesel costs have been on a steady incline.
Already solar-generated power is cheaper than diesel: diesel-produced electricity cost about $0.76 per kWh and solar-produced electricity is at $0.71 per kWh, even with installation costs factored into the equation.
The solar farm on Alcatraz is installed on the former main cellhouse building and is a 307KW photovoltaic system that includes an independent microgrid. Any excess energy is stored with a two megawatt per hour lead-acid battery.
Although the diesel generators are still on site to act as an emergency backup, the entire island has been operating on 100 percent solar power. The one million annual visitors to Alcatraz will learn about the solar farm as part of their tour of the island.