Previously , the plan to transition Alcatraz Island to some degree of solar power, and off of diesel generators, was discussed. That was about two years ago, and now that plan has come to fruition. About two thousand gallons of diesel fuel were being used per week to generate electricity on the small island.

Now, they have a 307-kW photovoltaic solar system, and their own microgrid. What used to be the main cellhouse building, containing dangerous criminals, is now the site of many solar panels. Next to the new solar power plant is a two-megawatt-per-hour lead-acid battery for storing surplus energy. (The development of a solar system on the island coincided with declining solar technology costs and rising diesel prices.) All of the island’s electricity demand can be met by the solar system, but diesel generators are used to fill in when needed.

Before the solar power microgrid was completed, the island’s electricity cost the National Park Service about $0.76 per kWh. Now that cost is about $0.71 per kWh, including the cost of the solar plant’s construction.

While a 307-kW solar system on a small island in the San Francisco Bay may seem like ‘small potatoes’ to some, consider the fact that over one million visitors are there each year. Of course, a big part of the Alcatraz experience is the educational aspect focused on the history of the prison and who the inmates were. Now, a portion of what visitors learn about is clean energy, and that educational component will be in place for many years to come.