In-state hydropower output dropped 50% from the norm in California in 2014. The difference is being made up with increased use of natural gas, as well as wind and solar. However, natural gas power does require substantial amounts of water for cooling, creating a bit of a Catch-22. California also imports large amounts of energy from big hydro in Washington and coal plants in Utah, Arizona, and New Mexico.
California’s drought, which began in 2011, has resulted in a significant decline in hydropower generation. On average, hydropower accounted for 20% of California’s in-state generation during the first six months of each year from 2004 to 2013. During the first half of 2014, however, hydropower accounted for only 10% of California’s total generation. Monthly hydropower generation in 2014 has fallen well below the 10-year range for each individual month.
Wind and solar generation are also playing an increasingly significant role in California’s generation mix. For the first time, wind generation surpassed hydro generation in California, doing so in both February and March of 2014.
The Columbia River Basin in Washington supplies 40% of hydropower in the US. Some parts are in drought but nowhere near as severe as California.