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Nathan Bowe, Published January 20 2014

Group of Minn. cities eyes unusual new power source

DETROIT LAKES, Minn. – A group of city-owned utilities in western Minnesota – including Detroit Lakes, Lake Park and Moorhead – is looking at an unusual source of new power: a “pumped storage” hydroelectric project along the Missouri River in south-central South Dakota.

“It’s a huge project. It will take a number of utilities coming together to make it happen,” said Bill Radio, public relations director for Missouri River Energy Services.

Annual generation of the project is estimated at 3 million megawatt-hours of energy – enough to meet the electrical needs of 250,000 to 300,000 average homes.

The Federal Energy Regulatory Commission has issued a preliminary permit to the Western Minnesota Municipal Power Agency to study the feasibility of the Gregory County Pumped Storage Project.

WMMPA filed for the permit July 30.

If built, it will be located on Lake Francis Case on the Missouri River in Gregory, Charles Mix and Brule counties in South Dakota.

A pumped storage project works by pumping water from a lower-elevation reservoir to a higher-elevation reservoir, where the water is stored.

Pumping would occur during low-cost times, often during the overnight hours, Radio said. Then, during times when electricity prices are high, the stored water is released through turbine-generators to produce electricity.

In this case, the water would be drawn from the Missouri River and released back into the Missouri River, Radio said.

Early stages

The Gregory County Pumped Storage Project would consist of a new upper reservoir with a storage capacity of 47,000 acre-feet, a powerhouse containing eight 100-megawatt turbine units, a new tailrace from the powerhouse to Lake Francis Case, a new substation and transmission lines, and other necessary facilities.

The study is in its early stages and no cost estimate for the project is available, Radio said.

But options for steady, base power generation are limited, he said, especially with new Environmental Protection Agency rules that would set the first-ever limits on carbon dioxide emissions on power plants at levels that discourage coal as an energy source.

“The options now for what you can build to meet future growth needs are very few – different kinds of renewables and natural gas, that’s about it,” he said. “I don’t want to say it would be built regardless of cost – our members always are concerned about that – but whatever we do will be more expensive than what we were used to in the past.”

Help meet requirements

The history of the Gregory County concept dates to 1977, when a U.S. Army Corps of Engineers study identified the area as the best location on the Missouri River for a pumped storage project.

Since that time, there have been several technical and economic studies related to the project.

The hydro project would help Minnesota city-owned utilities meet the state’s renewable fuel requirements of 25 percent by 2025.

And the project would create infrastructure friendly to wind turbine generation.

“Gregory County has an added benefit in that it would provide the necessary control to support a significant amount of intermittent wind generation in the region,” said Ray Wahle, director of power supply and operations for Missouri River Energy Services.

Wind energy facilities can produce electricity only when the wind is blowing, meaning that other generation sources are needed to maintain a reliable baseline flow of energy.

The permit is in effect for three years or until the Western Minnesota Municipal Power Agency submits to the Federal Energy Regulatory Commission a development application for the project and that application is accepted for filing.

The WMMPA has a formal relationship through which it finances generation and transmission facilities for members of Missouri River Energy Services.

WMMPA’s membership primarily includes the Minnesota members of Missouri River Energy Services, including Lake Park, Moorhead, Henning, Wadena, Staples, Barnesville, Breckenridge, Elbow Lake and Alexandria.