California's severe drought could cut its summer hydropower generation nearly in half from 15% of the state's electricity under normal conditions to 8%, the U.S. Energy Information Administration said in a new analysis.
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EIA's Short-Term Energy Outlook (STEO) forecasts for California hydroelectric generation currently rely on a simple econometric model that assumes monthly generation in the future will mimic average historical patterns.
"In our Drought case, we found that California’s summer hydroelectric share of generation mix was nearly halved, falling from 15% to 8%.
"To offset the reduction in hydroelectric generation, California purchases more electricity from neighboring markets and increases in-state natural gas generation, which rises from 45% in the Median case to 50% of total summer generation mix in the Drought case.
"In the Drought case, increased natural gas generation contributed to higher modeled wholesale electricity prices, as well as an increase in CO2 emissions.
"The analysis in this STEO supplement focuses on the drought’s effect on hydropower generation in California.
"Though the impact of drought on water-cooled thermal power plants was not explicitly modeled here, it is not expected to have a significant near-term effect on thermal generation in California."
California purchases more electricity from neighboring markets and increases in-state natural gas generation, which rises from 45% in the Median case to 50% of total summer generation mix in the Drought case.
"We found that California’s total summer hydroelectric generation (from June to September) in 2022 would fall from 13 million MWh in the Median case to 7 million MWh in the Drought case, a 48% drop in hydroelectric generation and comparable to generation in 2015 (Figure 8).
"As a result, hydroelectric generation’s share of total summer generation falls from 15% in the Median case to 8% in the Drought case (Figure 9).
"The replacement power to make up for the reduced hydroelectric generation is about evenly divided between an increase in out-of-state market purchases and in-state natural gas generation.
"In-state natural gas generation in the Drought case is 8% higher than the Median Case, with the natural gas share of generation rising from 45% to 50% of total summer generation to make up for the reduced share from hydropower.
"Given identical load between the two cases, the additional rise in natural gas generation in California leaves 2.9 million MWh to be made up by imported power.
"Although California already makes out-ofstate market purchases to meet one-third of its electricity demand, WEIM provides another opportunity to import electricity.
"The real-time nature of WEIM matches well with California’s greater need for resources that can respond quickly to the within-the-hour-generation variability characteristic of solar and wind resources." ■