Out Of Thin Air: California has set ambitious targets for renewable energy generation for the state. Wind power, including electricity generated by these turbines at the Altamont Pass wind farm east of San Francisco, will play a key role in meeting the state's goals. Justin Sullivan/Getty Images hide caption
This composite illustration shows what a proposed solar array built by Solargen Energy in the Panoche Valley would look like from ground level. Solargen Energy hide caption
This shipping container turned battery holds enough power for 1,500 homes and is made of 83,000 small lithium-ion battery cells. Electric grid operators can use battery technology like this to help smooth out fluctuations in electricity as a result of the irregularities of using renewable sources like wind and solar power. Lauren Sommer/KQED hide caption
Renewable energy advocates are looking to geothermal sources like this plant in Calipatria, Calif., to provide electricity to help California meet its goal of generating 33 percent of its power from renewable sources by 2020. But some conventional geothermal sites are, quite literally, running out of steam. David McNew/Getty Images hide caption
The Campo Kumeyaay Nation, a desert tribe east of San Diego, currently leases land to the only large-scale renewable power facility on tribal land in the country. Amy Standen/KQED hide caption
