Minnesota power agency works with Corps on Iowa hydro project

The Western Minnesota Municipal Power Agency on Oct. 23 filed with the Federal Energy Regulatory Commission a Regulating and Operating Plan for an up-to-55-MW hydro project in Iowa.

The plan has been developed in consultation with the U.S. Army Corps of Engineers, which by letter issued Oct. 21 concurred with the plan. The project would be built at the Corps’ existing Red Rock Dam.

The plan has been developed by Western Minnesota Municipal Power Agency (WMMPA) to describe: the designed mode of hydropower operation; reservoir flow diversion and regulation requirements for operation of the Corps project during construction; and integration of the operation of the hydro facility into the Corps’ emergency action plan.

In April 2011, CRD Hydroelectric LLC obtained an original license from FERC to construct, operate and maintain the Red Rock Hydroelectric Project. In January 2012, FERC approved transfer of the license from CRD Hydroelectric to WMMPA. In April 2012, FERC issued an order amending the license to reflect changes that reduce impacts on the dam’s existing structures and improve constructability and dam safety.

This project includes:

  • an approach channel and stand-alone intake structure;
  • a powerhouse containing two vertical Kaplan units, each connected to a generator and fed by two reinforced concrete penstocks with steel lining on downstream side of the dam 
(one for each unit);
  • a tailrace channel; and
  • a substation and 4.5-mile-long, 69-kV transmission line between the powerhouse and the City of Pella West Substation, parts of which will be buried (a total 
of about 1.24-miles or 6,520-feet) and the remainder of which will be overhead.

The concrete powerhouse will be built directly downstream of the existing dam and to the left of the spillway gates. The 185-foot-long and 127-foot-wide powerhouse will contain two vertical Kaplan units, each connected to a generator. Two reinforced concrete penstocks (one for each unit) will provide water from the intake to the units. The penstocks will be steel lined on the downstream side of the dam.

As licensed, the project is rated at 36.4 MW at rated head, rated flow, and best gate efficiency. Under certain conditions (high head/high flow), the project will be capable of generating up to 55 MW.

About Barry Cassell 20414 Articles
Barry Cassell is Chief Analyst for GenerationHub covering coal and emission controls issues, projects and policy. He has covered the coal and power generation industry for more than 24 years, beginning in November 2011 at GenerationHub and prior to that as editor of SNL Energy’s Coal Report. He was formerly with Coal Outlook for 15 years as the publication’s editor and contributing writer, and prior to that he was editor of Coal & Synfuels Technology and associate editor of The Energy Report. He has a bachelor’s degree from Central Michigan University.