Coal and natural gas rank second and third and then is nuclear power with less than 10 percent.
Alternative fuels such as solar, wind, even ethanol account for just 6.8 percent of our energy use.
Will there be a day when the sun, wind and agriculture replace coal, natural gas and oil as energy sources?
"Well we're well on the way in California but nationally we haven't even really started to get serious," said Dan Kammen from U.C. Berkeley.
U.C. Berkeley Energy and Resources Group professor Dan Kammen says we don't need 100 percent replacement of existing sources to make a difference.
"We would get a long way towards reaching the climate goals, and more immediately reducing the price increases we are seeing at the pump by simply bringing down our demand. Even curtailing the growth and demand would impact because it would take the pressure off in many of those areas," said Kammen.
There's a moratorium on nuclear plants in California until a new method of disposing spent fuel is found and even then, nuclear plants won't produce liquid fuels for cars.
The biofuel industry, once seen by many as the renewable answer to gasoline, is increasingly complicated because of land-use impacts.
California has a goal of 20 percent renewables by the year 2010. PG&E says its already got renewable energy contracts accounting for 22 percent of its energy generation.
Hal LaFlash is a PG&E Director of Emerging Clean Technology Policy.
"A lot of solar, geothermal, wind and wave, a lot of biomass and hydro along with that," said LaFlash.
LaFlash says PG&E is also working on ways to someday get its clean energy into electric vehicles on the street, but there are challenges.
"One of the biggest difficulties right now is that most renewables require some kind of tax credit to be economic and the tax incentives are caught up in Washington right now," said LaFlash.
California is giving a $4,100 dollar rebate to homeowners who buy $20,000 dollar wind turbine. They are available from a company called Fresco Solar.
"They generally require some kind of subsidy for them to make sense. That's just where the technology's at," said Sean Kenny from Fresco Solar.
CEO Sean Kenny says it will pay for itself in five to eight years.