Grandfather Falls Hydro Plant Penstock Replacement

The Grandfather Falls Hydroelectric Power Plant is located 13 miles north of Merrill, Wisconsin, on the Wisconsin River and has two units with a total of 17.1 MW of generation capacity. This project, constructed for Wisconsin Public Service (WEC Energy Group), included the demolition and replacement of existing dual wood stave penstocks. Leakage from these pipes had increased four-fold over the past two years and was occurring between the wood staves and butt joints. Each new welded steel penstock waterline stretches 1,300 LF with one pipe 156″ and the other pipe 132″ in diameter. The project also included storm drainage piping, concrete thrust blocks, coatings, and site restoration.