Mossyrock Dam is a concrete arch-gravity dam on the Cowlitz River near Mossyrock in Lewis County, Washington. The reservoir created by the dam is called Riffe Lake and the primary purpose of the dam is hydroelectric production while flood control is secondary.
The dam is the tallest in Washington State and its hydroelectric power station supplies 40% of Tacoma Power's electricity.
The Mossyrock Dam's power plant contains two Francis turbine hydroelectric generators, each rated at 150 MW, or 300 MW total capacity. They are fed by three penstocks ranging from 248 – 285 feet in overall length. One of the three penstocks is presently unused, awaiting possible future installation of a third turbine.
In 2006, GE Energy was selected to upgrade the two turbines. The $50 million project included replacing the turbines, stators, wicket gates and transformers. Installation of the first generator began in 2008; it began operation in 2009. Replacement of the second generator was completed in late 2010. The power plant upgrade increased the total capacity by 70 MW, with an expected overall energy-conversion efficiency of near 95 percent. More details
The dam is the tallest in Washington State and its hydroelectric power station supplies 40% of Tacoma Power's electricity.The Mossyrock Dam's power plant contains two Francis turbine hydroelectric generators, each rated at 150 MW, or 300 MW total capacity. They are fed by three penstocks ranging from 248 – 285 feet in overall length. One of the three penstocks is presently unused, awaiting possible future installation of a third turbine.
In 2006, GE Energy was selected to upgrade the two turbines. The $50 million project included replacing the turbines, stators, wicket gates and transformers. Installation of the first generator began in 2008; it began operation in 2009. Replacement of the second generator was completed in late 2010. The power plant upgrade increased the total capacity by 70 MW, with an expected overall energy-conversion efficiency of near 95 percent. More details