Solar startup BrightSource will build a solar thermal plant in California for oil giant, Chevron.

Chevron isn't using the solar plant for electricity, it's using it for steam generation, which will be used for getting oil out of the ground.

Reuters explains it:

The second-largest U.S. oil company said the solar thermal plant, which will collect reflected sunlight from thousands of mirrors at a 323-foot (98-meter) tower where the water boils, will replace some steam production now powered by natural gas.

Steam is injected into wells to heat up heavier oil and thus lower its viscosity to make it easier to extract.

...Although [Sergio Hoyos, a business developer at Chevron Technology Ventures] said solar thermal could never replace natural gas in steam production, it is an opportunity for Chevron to save energy while championing a technology pegged by some as a winner in the long run.

It's also an opportunity for Chevron to reduce its carbon emissions. If the cap and trade bill is passed, Chevron might even get big carbon rebates for investing in this technology.