Backers drop plan for massive energy storage project at Missouri River site

Backers of a multibillion-dollar proposal to build a giant reservoir for energy storage in rural south-central South Dakota said Tuesday they are no longer pursuing the project at that location.

“Not due to the opposition. Due to the financial risk of the project,” said Tim Blodgett, vice president of member services and communications for Missouri River Energy Services in Sioux Falls.

There was considerable public opposition to the project, expressed in the media and in formal written comments and public meetings.

The plan was called the Gregory County Pumped Storage Project. It would have included the construction of a massive new reservoir above the western bluffs of the Missouri River, about 20 miles northeast of Gregory. Pumped storage projects work like colossal batteries. They pump water into a reservoir when electricity demand is low, thereby storing excess energy produced by renewable sources like wind and solar panels. Then, when demand is high, the water is released through a hydroelectric plant.

The two entities involved, MidAmerican Energy and Missouri River Energy Services, said the decision not to pursue the project was made following their evaluation process. 

Missouri River Energy Services announced the decision to abandon the project in a news release Tuesday. Blodgett told South Dakota Searchlight the company remains committed to exploring all possible options for delivering reliable, affordable and resilient energy resources, including continued evaluation of pumped storage technology.

“For us, this is not the end of us pursuing pumped storage along the Missouri River,” Blodgett said. “This is just the end of this project.”