Drought spurred by climate change cut 2024 U.S. hydropower to its lowest level in 18 years
Energize Weekly, November 13, 2024
U.S. hydropower plants – beleaguered by drought and above average temperatures – are projected to produce 13 percent less electricity in 2024 than the 10-year average, according to the federal Energy Information Administration (EIA).
This would be the smallest amount of electricity generated from hydropower since 2001. “Extreme and exceptional drought conditions have been affecting different parts of the United States, especially the Pacific Northwest, which is home to most U.S. hydropower capacity,” the EIA said.
The Pacific Northwest is part of the EIA’s Northwest electricity region, which also includes parts of Rocky Mountain states.
The agency projects hydropower generation in the Northwest electricity region to total 101.8 billion kilowatt-hours (kWh) in 2024, a 23 percent decrease from the 10-year average of 132.8 billion kWh and a 1 percent decrease from 2023.
At the end of September, 72.6 percent of the continental United States was experiencing dryer-than-normal to exceptional drought conditions, by the end of October that had edged up to 87.2 percent, according to the U.S. Drought Monitor.
The National Oceanic and Atmospheric Administration (NOAA) said October 2024 is likely to be one of the driest months ever recorded for the U.S. and that conditions are not projected to improve for November.
“Multiple regions are affected by drought conditions, but the effects on hydropower generation are more obvious in the Pacific Northwest,” the EIA said.
A University of Alabama study found hydropower generation was most vulnerable to drought in California and Washington state based on data from 2003 to 2020.
During that 18-year period, the University of Alabama researchers calculated that drought events led to a decline of approximately 300 million megawatt-hours of electricity resulting in an estimated loss of $28 billion to the sector.
The problem is not only a lack of rain, but hotter temperatures – a result of climate change – which evaporate more water from surface supplies.
A NOAA study found evaporative demand, or the “thirst of the atmosphere,” has played a bigger role than reduced precipitation in droughts since 2000. During the 2020-2022 drought, evaporation accounted for 61 percent of the drought’s severity, while reduced precipitation accounted for only 39 percent.
The Pacific Northwest’s Columbia River Basin – covering parts of Washington, Oregon, Idaho and Montana – is home to several of the largest hydropower dams in the county, including the 6.7-gigawatt Grand Coulee and the 2.4-gigawatt Chief Joseph.
Starting in April, the Washington State Department of Ecology declared most of the counties in the state under drought, a move made when the state’s water supply is less than 75 percent of normal.
In Oregon, Jefferson County declared a drought emergency in June, and in September, Lake County followed suit.
“The Dalles Dam located between Oregon and Washington, with a total net summer capacity of 1.8 GW, is considered a good indicator of water supply conditions in the upper Columbia River,” the EIA said.
Water supply at The Dalles Dam at the end of September was at 74 percent of the 30-year normal for the April-to-September period – the peak generation period to meet summer seasonal demand, according to the Northwest River Forecast Center.
Reservoir storage at the end of September was 48 percent of capacity in Oregon, 67 percent of capacity in Washington, 76 percent in Montana, and 60 percent in Idaho, according to the U.S. Department of Agriculture’s Basin Outlook Report.
