Chevron will partner with BrightSource Energy to develop 29 megawatts of thermal power from the sun. The process uses mirrors to concentrate the solar rays onto a water tank, turning the water to steam. The steam can then be used to turn a turbine and produce electricity or pumped down a well to loosen heavy oils.

The plant slated for the Coalinga Oil Field near Fresno will employ at least 3,000 mirrors to concentrate light on a more than 300-foot tower with water inside. Chevron hopes it will be fully operational by the end of next year. “The only problem we have is when it’s cloudy,” said Sergio Hoyos, a business developer at Chevron Technology Ventures.

Currently, oil companies like Chevron will usually burn natural gas to produce the steam necessary to get the oil going, and that method probably still be used at night and part of the day.