California's worsening drought could disrupt hydropower electricity generation this summer

California's drought is getting worse — and the drying lakes and reservoirs could severely disrupt the state's ability to generate electricity ahead of the hot summer months.

California's energy commission says the state gets 10% of its electricity from power plants at dams along lakes and reservoirs. But when there's no water, those plants are unable to generate power.

"As we have the continued drought, the availability of hydropower in California has been significantly undercut," power grid expert Steven Weissman said.

According to a report from the U.S. Energy Information Administration, Shasta Lake and Oroville Lake — which supply water to two of the state's hydropower plants — are at historically low levels. Shasta, the largest hydroelectric facility in the state, generated 46% less power last year, compared with a 10-year average. Meanwhile Oroville, the second-largest reservoir in California, hit record low levels, forcing the Edward Hyatt hydropower plant to go offline for the first time. Officials say electricity generation from Edward Hyatt in 2021 was 81% than the 10-year average.

Last year, the summer months were the hottest on records across the contiguous United States, according to NOAA, prompting several flex alerts in California.

In spite of the unseasonably high temperatures forecast for much of California this week, there are no flex alerts planned in the immediate future. However, experts are predicting the worsening drought will strain the state's power grid even more this summer.