Decline in hydropower puts pressure on power grids in times of drought
After water levels at a California dam fell to historically low levels this summer, the main hydroelectric plant it powers was shut down. At the Hoover Dam in Nevada, one of the largest hydroelectric generators in the country, production fell 25%. If an extreme drought persists, federal officials say a dam in Arizona could stop producing electricity in years to come.
A severe drought in the west has drained reservoirs this year, reducing hydropower production and further straining the region’s power grids. And as extreme weather conditions become more common with climate change, grid operators are adjusting to fluctuations in hydropower production.
“The challenge is finding the right resource, or the right mix of resources, that can deliver the same energy and power as hydropower,” said Lindsay Buckley, spokesperson for the California Energy Commission.
U.S. hydropower production is expected to decline 14% this year from 2020, according to a recent federal forecast. The projected declines are concentrated in Western states that are more dependent on hydropower, with California output set to fall by nearly half.
The reductions complicate grid operations, as hydropower is a relatively flexible renewable energy source that can be easily scaled up or down, experts say, such as in the evening when the sun goes down and solar power production declines. .
“Hydropower is an important part of the plan to make the entire system work,” said Severin Borenstein, renewable energy expert at the University of California at Berkeley and a board member of the California Independent System Operator. , which manages the state’s electricity grid.
Borenstein noted that hydropower is important as the state works to expand its electricity storage options, including installing batteries that can deliver power when needed.
Ben Kujala of the Northwest Power and Conservation Council, which manages energy planning for the Columbia River Basin, also noted that grid operators have adapted the way they deploy hydropower in recent years to ensure it complements solar and wind power.
Power grids connecting the western regions also offer some relief. While California can face periods of dry weather over several years, the Pacific Northwest generally receives enough precipitation in the winter to recover and produce hydropower for export.
But this year, the Northwest was also hit by extreme heat and less precipitation, according to Crystal Raymond, a climate change researcher at the University of Washington. As energy planners factor in years of drought, Raymond said long-term climate change could further reduce the amounts of melting snow in the mountains that fill reservoirs in the spring.
In August, California authorities shut down the Edward Hyatt hydroelectric plant for the first time in its 60-year history after Lake Oroville water levels hit historic lows. The plant can produce enough electricity for up to 750,000 homes, but generally operates at lower levels.
At Lake Powell, on the Arizona-Utah border, federal officials recently said there was a 34% chance that the Glen Canyon Dam would not be able to generate electricity at a given time in 2023, up from 3% for next year, if extreme drought persists.
The decline in hydroelectric generation in California this summer coincided with heat waves, forcing the state to purchase additional electricity. To avoid blackouts in late September, state officials said they were deploying temporary emergency generators.
“The drought has made it more difficult to meet demand,” said Jordan Kern, an energy and water systems expert at North Carolina State University.
In some northwestern states, hydropower production has returned to nearer-normal levels after dropping just below their 10-year ranges earlier this year. California hydropower levels remained at the low end of the state’s 10-year range until June. Federal forecasts indicate that much of the west is expected to continue to experience drought conditions until the end of the year.
Declines in hydropower production mean production bumps for other energy sources. Natural gas electricity is expected to increase 7% in California and 6% in the Northwest this year from last year, according to federal forecasts. Coal production is expected to increase 12% in the Northwest.
The California Air Resources Board says the state has been able to continue reducing greenhouse gas emissions from the electricity sector despite fluctuations in hydroelectric production in recent years.