Drought is forecast to slash California’s supply of hydroelectricity in half this summer. That’s bad news for residents’ air quality and utility bills, the US Energy and Information Administration (EIA) said in its forecast. The state will likely lean on more expensive, polluting natural gas to make up for the shortfall in hydropower.

Nearly 60 percent of California is currently coping with “extreme” drought or worse, according to the national drought monitor map. California’s current water woes stem from low levels of snowpack, which quenches the state’s reservoirs when it melts. In early April, when snowpack usually peaks, the water content of the state’s snowpack was 40 percent lower than the normal levels over the past 30 years.

Image: Richard Heim, NOAA/NCEI

Two of California’s most important water reservoirs, Shasta Lake and Lake Oroville, were already “critically low” by early May. We haven’t even reached the summer, when the weather could become even more punishingly dry and hot and demand for air conditioning places extra stress on the power grid.

Hydroelectricity is a significant source of energy in the US. It typically makes up about 15 percent of California’s electricity generation during “normal water conditions,” according to the EIA. But that’s expected to drop to just 8 percent this summer, the EIA says.

Sometimes California can buy hydropower from other states in the Pacific Northwest. But Washington State and Oregon are also dealing with drought, so gas may have to fill in the gaps. As a result, the EIA says electricity prices in the Western US will likely be 5 percent higher over the next few months. In California, the drought will result in 6 percent higher carbon dioxide emissions in the energy sector.

California is no stranger to drought, but things have gotten historically bad this year. The first few months of 2022 were the driest in over 100 years. Governor Gavin Newsom has asked Californians to voluntarily change their habits — including taking five-minute showers instead of baths and sweeping rather than hosing down outdoor areas when cleaning — in an effort to reduce the state’s water consumption. In some places, local governments are mandating water cuts. Starting today, many residents in the Los Angeles area will only be allowed to water their lawns once a week.

As climate change shapes a future with worsening droughts, it could become difficult for the US to rely on hydropower as a clean energy source to reach its climate goals. The nation relied on hydropower for nearly a third of its renewable electricity in 2021. The Biden administration has a goal of getting the US power grid to run completely on carbon pollution-free energy by 2035.