Persistent drought in the West over the last two decades has limited the amount of electricity that hydropower dams can generate, costing the industry and the region billions of dollars in revenue. The sector lost about 300 million megawatt hours of power generation between 2003 and 2020 due to drought and low water compared with the long-term average, researchers from the University of Alabama found. That equals about $28 billion in lost revenue. Half of the drop in power generation was due to drought in Oregon, Washington and California, which produce half the hydropower generated in the U.S. The researchers published their findings July 23 in the journal Environmental Research Letters.