The large-scale adoption of electric vehicles will increase demand for hydropower and put more pressure on water supplies in Eastern Washington, according to a new Washington Department of Ecology forecast for the Columbia River Basin.

Along with population growth and data centers, electric vehicles are expected to drive demand for hydropower by up to 34% by 2040.  

Washington PUD Association Deputy Executive Director Liz Anderson said it was conceivable that efficiencies, pumped storage and selling less power to other states could increase the availability of hydropower.

“It is not realistic to believe that the existing hydropower system can increase output by 34%,” she said in an email Thursday.

“Especially given the operating constraints on the system to support fish and considering the discussions around the removal of the four Lower Snake River dams,” she said.

Ecology collaborates with Washington State University every five years to forecast water supply and demand in the Columbia River Basin for the next 20 years.

The basin spans portions of seven states, including Washington east of the Cascades. The University of Utah and Aspect Consulting contributed to the forecast.

Because of climate change, November through May will be wetter and June through October will be drier, according to the forecast. Overall, the water supply is expected to increase slightly in an average year. 

Agriculture is the largest out-of-stream user of water. Agricultural water use is expected to remain fairly steady, though irrigators can expect peak water supplies to come earlier.

The forecast cites the connection between electric vehicles and the demand for water.

The forecast projected up to 837,902 registered electric vehicles by 2040, compared to 51,036 in 2020, according to an Ecology spokeswoman. All new cars and light-duty pickups must be electric by 2030, according to a state goal.

Minus electric vehicles and data centers, demand for hydropower could grow by as little as 5%, according to the forecast.

“Though significant uncertainty remains around which factors will actually drive demand for electricity, it is clear that demand for hydroelectric power is likely to increase,” the forecast states.

Combined with efforts to restore fish runs, “this will place further pressure on limited (water) supplies,” the forecast states.

Besides meeting more demand, electric utilities will have to replace energy generated by coal and natural gas.

The state’s clean-energy law bars utilities from using new or expanded hydropower projects to meet their obligation to be carbon-neutral by 2045.

“It is difficult to say with confidence how utilities will meet greenhouse gas neutrality goals,” according to the forecast.

The Biden administration, Gov. Jay Inslee and Sen. Patty Murray, D-Wash., continue to show interest in breaching the four Lower Snake River dams to help salmon and steelhead.

A draft report done as part of the Inslee-Murray process for looking at removing the dams said the dams produce carbon-free electricity and help the region meet peak demands in the winter.

Breaching the dams, according to the report, would roughly double the chances electric utilities would have to “shed load or take other undesirable emergency actions.”