The Federal Energy Regulatory Commission on Oct. 25 approved some design changes requested by the Western Minnesota Municipal Power Agency for its licensed and so far unbuilt Red Rock hydroelectric project in Iowa.
The project is located at the U.S. Army Corps of Engineers’ Red Rock Dam on the Des Moines River in Marion County, Iowa. The Corps operates the dam for flood control and recreation purposes, providing a daily discharge based on stream flow and reservoir conditions.
The hydroelectric project, as licensed, would include:
- a powerhouse located directly downstream of the existing spillway that will house two 18.2-MW generators with vertical Kaplan turbines and have a total installed capacity of 36.4 MW;
- aeration systems installed on the project turbines;
- air injection on the project turbines; and
- a 4.5-mile-long, 69-kV transmission line.
The project was amended in April 2012 to include a redesigned intake and powerhouse, and to install two units instead of three. The licensee states that the reason for this latest amendment is to capture the changes in the project geometry as a result of the development of the detailed design of the project since the previous amendment.
It plans to modify the intake structure, the penstock geometry, the penstock liner, the reinforced concrete diaphragm wall, the cutoff wall, the temporary construction laydown yard/future vehicle turnaround at the intake structure, the flow bypass conduit, the substation elevation, and eliminate the upstream submerged weir.
On April 22, the commission issued an order extending the deadline to commence construction to April 18, 2015, and to complete construction by April 18, 2018. The licensee provided in its amendment application a revised construction schedule, which falls within the authorized construction period of license Article 306.