The vegetation at Yosemite National park has run on solar energy for millions of years. Humans are finally following nature's example and using solar panels to power their facilities.

The park installed a 672-kilowatt solar panel system just outside the park’s boundaries in El Portal, California. 8-by-12-foot solar panels fill almost every available space on rooftops and sides of buildings, as well as the roofs of carports and parking garages at Yosemite’s Administrative Complex.

The solar array began operating at the end of June. The Administrative Complex in El Portal, its visitor facilities in the park and the Ahwahnee Hotel in Yosemite Valley have been powered by solar energy since then. Contractors finished the 2,800 panel system last February, but Pacific Gas and Electric (PG&E) needed time to inspect the panels and install equipment to connect Yosemite’s solar panels to their grid.

The solar panel array is the largest grid-connected solar panel system operated by the National Park Service.

Yosemite’s solar panels will provide 800,000 kilowatt-hours of electricity each year. This cuts the park’s use of electricity from PG&E by almost 12 percent. It is estimated they will save almost $50,000 a year in electricity purchases.

Overall, Yosemite’s solar panel system cost $4.4 million. Funding came from the $754 million reserved for the national park system from American Recovery and Reinvestment Act funds. Not only did the project develop an efficient energy source, it also reduced pollution and provided jobs.

Yosemite’s new system has double the amount of solar panels as the array installed on Alcatraz in San Francisco Bay. The Alcatraz site has 1,300 panels.