An Idaho company has gotten approval to explore building a dam and reservoir near Prineville to store water for generating electricity.
The developers envision the project called “pumped hydro storage” as a complement to balance intermittent supplies from such sources as wind turbines, the Bend Bulletin reported.
The project would create a smaller dam and reservoir above Bowman Dam and the Prineville Reservoir, which supplies irrigation water.
Water would be pumped uphill at night from the larger reservoir into the smaller one.
During the day, when power demand is high, it would flow downhill through turbines to generate electricity and flow back into the larger reservoir, to be pumped again to the smaller one for a new round of generation.
An underground powerhouse would contain three 50-megawatt turbines and generate enough electricity for about 30,000 homes.
The Federal Energy Regulatory Commission granted a preliminary permit July 19 to Prineville Energy Storage LLC, an affiliate of Boise-based Gridflex Energy. It allows a feasibility study for a 40-foot dam and reservoir.
The Bowman Dam is 240 feet tall, and the Prineville Reservoir behind it covers 3,030 acres. The upper reservoir used for power generation would cover 57 acres.
The process known as pumped hydro storage has been around for 100 years, said Matthew Shapiro, CEO of Gridflex Energy.
“It’s the oldest form of large-scale energy storage,” he said.
Gridflex Energy has about 15 pumped hydro storage projects under development in nine states, according to its website.
Federal energy experts see the need for energy storage as the nation generates more electricity from sources like wind and solar, which produce electricity only when the wind blows and the sun shines.
But in the current market and with existing regulatory hurdles, building new hydropower plants for pumped storage may not be cost effective, according to an April study conducted for the U.S. Energy Department. However, the market is likely to change, the report said, which could provide more incentive to build.
A decision from the federal energy agency said concerns raised by the U.S. Bureau of Reclamation and two irrigation units could be addressed if Gridflex finishes the feasibility study and files for a license.