According to a study released by the U.S. Energy Information Administration (EIA) in May 2022, California’s extended drought could nearly halve its summer hydroelectric generation from 15% to 8%.[1] The study, titled “Short-Term Energy Outlook Supplement: Drought Effects on California Electricity Generation and Western Power Markets,” found that lower hydropower generation will bump up the state’s natural gas generation, leading to a 6% increase in carbon dioxide emissions from the state’s energy sector, and an average 5% increase in wholesale electricity prices across the region.

The state is currently in its third year of drought, and these conditions have impacted its hydropower resources, which is usually the state’s third largest source of electricity. Many of California’s reservoirs have low levels of storage at the moment; the two largest — Lake Shasta and Lake Oroville — were at 48% and 67% of historical storage averages, respectively, as of April 1, 2022. The EIA stated that hydroelectric generation in 2021 was 48% lower than the state’s 10-year average. These drought conditions come as the state transitions toward more clean sources of energy. The study notes that about 6.5 GW of natural gas units have been retired since 2015, while solar capacity has increased by 8.8 GW in that same period. Even accounting for added battery storage capacity, California’s total share of dispatchable resources is lower in 2022 than it was in 2015.

[1] https://www.eia.gov/outlooks/steo/special/supplements/2022/2022_sp_02.pdf