A pumped storage project study for the Missouri River in Gregory County from a Minnesota-based power authority has received initial approval from the Federal Energy Regulatory Commission.

The preliminary permit, issued Sept. 7, allows the Western Minnesota Municipal Power Agency to study the feasibility of the 1,200-megawatt project for the next three years. The site would be about five miles northeast of the tiny Gregory County unincorporated village of Lucas, about 13 miles northeast of Burke and 15 miles southwest of Platte.

The WMMPA, a municipal corporation based in Ortonville, Minnesota, has filed the permit. It finances the construction and acquisition of generation and transmission facilities for members of Missouri River Energy Services, based in Sioux Falls, which provides energy to a number of municipalities in South Dakota, North Dakota, Minnesota and Iowa. WMMPA and MRES previously held a similar permit that lapsed in 2016.

The preliminary permit application faced some opposition from the area's tribal entities. The Yankton Sioux Tribe stated that the permit should have been denied because of the 1858 treaty regarding land and water rights in Lake Francis Case. The tribe also asserted that fisheries and wildlife would be damaged from construction and operation of the plant, which would harm the tribe's right to fish and hunt.

"Because preliminary permits do not authorize construction and operation of the project and the development of a license application is not guaranteed, it is premature to enter into government-to-government consultation with the Yankton Sioux Tribe and Rosebud Sioux Tribe," wrote Janet Hutzel, the chief of the Midwest Branch of FERC's Division of Hydropower Licensing. "If and when Western Minnesota files its notice of intent to file a license application and preliminary application document the Commission will take steps to consult with the tribes."

The proposed project calls for an open-loop pump storage project, with an upper reservoir, which will cover 1,350 acres and be constructed by a 62-foot-high earthen levee. An open-loop project is one that is connected to a naturally flowing water feature, which in this case is lake Francis Case and the Missouri River, the lower reservoir in this case. An underground powerhouse would be located more than 600 feet below the river level, Missouri River Energy Services Manager of Generation Resources Brent Moeller said.

The idea's concept dates back to 1977, when the U.S. Corps of Engineers completed a study of water resources along the Missouri River, with the Gregory County site being the best location for a pumped-storage project. The state of South Dakota applied for a permit to study the idea in 2002, and a feasibility study in 2004 conducted for the Department of Environment and Natural Resources said it wasn't a favorable project considering the economic conditions of the time.

During low demand periods, water would be pumped up the side of the river bluffs - about 700 feet - to the levee reservoir. During high demand periods, the water would flow back down to the pumps and turbines and would be generated into electricity.