Though the prison closed in 1963, 1.4 million visitors now tour Alcatraz each year. “The Rock” has been powered for 75 years by diesel fuel ferried across the bay. In 2012, a 280 kW solar photovoltaic system was installed on the roof of the island’s main cell house and provides roughly 66% of the island’s electricity needs. The solar array operates in combination with an extensive battery-based energy storage system to maximize solar electricity generation and use.
Alcatraz solar project competing for 2014 Intersolar Award