Extreme Drought Could Shut Down a Hydroelectric Power Plant In California

Officials are preparing for the likelihood that California’s record breaking drought will come for its renewable energy stores. The West Coast state, which has been weathering wildfires, 126-year rainfall lows, and a historic heat dome, announced on Friday that it is preparing for a Butte County reservoir that supplies hydropower to dry up later this summer. 

This means that the Edward Hyatt power plant, located 75 miles north of Sacramento, is likely to shut down temporarily for the first time since opening in 1967, E&E News reported Friday. 

The plant, which runs on water from Lake Oroville, supplies 1,000 megawatts of power to California’s grid. Through reduced rainfall and dry conditions, the lake has seen its water levels fall steadily since May—they now sit around 15 percent lower than they were this time last year, and 25 percent below July, 2019 levels. 

Currently at 665 feet, the reservoir must fall an additional 35 to 45 feet before it can no longer power the Hyatt plant. For a state that’s already increasing its energy use to withstand extreme weather, this would not be good.

“Based on our May projections, we really didn't have 1,000 megawatts to lose,” Lindsay Buckley, director of communications and external affairs for the California Energy Commission, the state’s primary energy planning agency, told E&E News. “The climate impacts are coming at us hard and fast. We need all hands on deck, and that includes everyday Californians and just helping to conserve during these times.”

The amount of energy that California’s grid would lose if Edward Hyatt goes offline is only a sliver of its total peak demand (44,000 MW), but the state has been increasing its reliance on fossil fuels to make up for any lost power as the grid faces strain. Last week, Gov. Gavin Newsom lifted environmental restrictions on natural gas-fired power plants in a move to expand the state’s energy capacity. In the same executive order, he called on Californians to reduce their energy use from peak hours (4 to 9 p.m.) to lower the risk of rolling blackouts. 

Mohit Chhabra, senior scientist in the Natural Resources Defense Council’s Climate and Clean Energy Program, notes that the state’s grid should be able to handle a possible shutdown at the Hyatt plant. But withstanding future climate disasters will require a resilient grid, one that customers can depend upon without sacrificing their energy use.

“Vulnerable Californians need to adapt to climate change too,” Chhabra told Motherboard in an email. “For this they need efficient homes and appliances.” 

The plant’s shutdown represents a new, terrifying development in the feedback loop between climate change and grid resilience: Rising temperatures demand increased reliance on air conditioning and other cooling mechanisms, the energy use for which further contributes to climate change, and so on. In some parts of the country, like Texas, local electrical grids have proven unprepared to handle this strain. But the loss of hydropower, a renewable energy source, in response to extreme weather events like drought, is cause for concern.

“Climate change is increasing our need for clean electricity in the summer while decreasing summertime hydro availability,” Chhabra said. “To wean off gas in the long term, we need to plan for how future electricity demand and clean electric supply (especially hydro) will be impacted by climate change.” 

The possibility that drought would alter the Golden State’s hydropower capacity is not wholly new; in 2018, researchers at the University of California Irvine published a paper predicting that long-term drought would reduce the state’s hydro system’s spinning reserve (its unused, backup energy capacity to be used during periods of high strain) by 41 percent by 2046. The researchers called on grid operators to build additional reservoir capacity to prepare for this eventuality. 

This is the first time in the Edward Hyatt plant’s 54-year history that it would have to shut off, even temporarily. Its power generation is currently reduced in response to the reservoir shortage, and officials in the California Department of Water Resources (DWR) predict a complete shutdown won’t come until August or September. Though the state experienced similar droughts in 1977, 2014, and 2015, lake levels were high enough to withstand the need for shutdowns; this year’s drought could change that, the Department noted in an email to Motherboard.  

The Oroville Dam also powers another plant—the Thermalito Plant—in the same complex, but Yarbrough notes that this one would remain online with limited capacity, even if Hyatt shuts off. 

“DWR is taking actions to conserve as much water as possible within Oroville reservoir,”  John Yarbrough, assistant deputy director of the State Water Project at DWR said. “To ensure minimal amounts of cold water are available for when it is needed for the fall salmon run and for critical water uses in case drought conditions continue into 2022.”