Eastmain-1 hydroelectric generating station, commissioned in 2006, adds 480 MW to the installed capacity of Hydro-Québec's generating fleet.

In addition to the powerhouse, the development includes a dam across the Rivière Eastmain, a spillway on the right bank of the river and 32 dikes which hold back water contained in the reservoir, covering a surface area of 603 square kilometres.

A 315-kV transmission line connects the powerhouse to Nemiscau substation. A permanent 80-km access road was built from this substation to the powerhouse.