Western Minnesota Municipal Power Agency granted permit to study Gregory County Pumped Storage Project

SIOUX FALLS, S.D. – The Federal Energy Regulatory Commission (FERC) has issued a preliminary permit to the Western Minnesota Municipal Power Agency (WMMPA) to study a pumped storage hydroelectric project along the Missouri River in south central South Dakota. WMMPA filed for the permit July 30, 2013 to study the feasibility of the Gregory County Pumped Storage Project to be located on Lake Francis Case on the Missouri River in Gregory, Charles Mix, and Brule Counties in South Dakota.

WMMPA is an organization of 23 municipalities in the State of Minnesota that own and operate municipal electric distribution systems. All of the WMMPA members also are members of Missouri River Energy Services (MRES). WMMPA provides financing for generation and transmission facilities that are used to serve the wholesale electricity needs of 61 MRES member municipalities in the states of Iowa, Minnesota, North Dakota, and South Dakota.

The history of the Gregory County concept dates back 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.

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. Then, during times when electricity prices are high, the stored water is released through turbine-generators to produce electricity. “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 MRES. Wind energy facilities can only produce electricity when the wind is blowing, meaning that other generation sources are needed to maintain a reliable flow of energy.

If built, 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.

It is estimated that the annual generation of the project would be three million megawatt-hours of energy or enough to meet the electrical needs of 250,000 to 300,000 average homes.

The permit is in effect for three years or until WMMPA submits to the FERC a development application for the project and that application is accepted for filing.

For more information, contact MRES Member and Public Relations Director Bill Radio, phone: 605-338-4042;  e-mail: bill.radio@mrenergy.com.