In 2007, hydroelectric power plants produced 43,625 gigawatt-hours of electricity, or 14.5 percent of the total. Hydro facilities are broken down into two categories larger than 30 megawatts capacity are called "large" hydro. Smaller than 30 MW capacity is considered "small" hydro and are totalled into the renewable energy portfolio standards. The amount of hydroelectricity produced varies each year. It is largely dependent on rainfall.
California has nearly 400 hydro plants, which are mostly located in the eastern mountain ranges and have a total dependable capacity of about 14,000 MW of capacity. The state also imports hydro-generated electricity from the Pacific Northwest.
- 2007年度で43,625 GWhの発電量