States across the West are at risk of electricity shortages this summer as a crippling drought reduces the amount of water available to generate hydroelectric power.
Some of the region’s largest reservoirs are at historically low levels after a dry winter and spring reduced the amount of snowpack and precipitation feeding rivers and streams. The conditions are especially dire in drought-stricken California, where officials say the reservoir system has seen an unprecedented loss of runoff this spring—800,000 acre-feet, or enough to supply more than a million households for a year.
The California Department of Water Resources operates eight major hydroelectric facilities that are now forecast this year to be about 30% of their 10-year average generation, the agency said. Hydroelectric power, some of which was imported from other states, accounted for about 16% of California’s generation mix in 2019, according to state data. California needs all the electricity it can get when temperatures climb: The margin for error is slim when it comes to balancing supply and demand, so any reduction in generation capacity can pose significant challenges.
Meanwhile, streamflow forecasts for Utah, Wyoming, Colorado, New Mexico and Arizona are among the five driest on record, according to an update this month by the National Oceanic and Atmospheric Administration.
The Colorado River’s Lake Powell is projected to receive only 25% of the water it normally would between April and July, according to the agency. Lake Powell is the main reservoir that feeds Nevada’s Lake Mead, where the Hoover Dam is located. The dam is one of the nation’s largest hydroelectric facilities, capable of producing enough power to serve about 1.3 million people. About 23% of its output serves Nevada, and 19% serves Arizona. Most of the remainder serves Southern California.