ASME-Landmark:Rocky River Pumped-Storage Hydroelectric Plant

The Connecticut Light & Power Company pioneered the use of pumped storage in the United States at the Rocky River Plant, first operated in 1929.

The first hydroelectric plant in New England was built in 1889, just seven years after the world's first hydroelectric station went into operation in Wisconsin. But these were small-scale experimental facilities, and the first large-scale hydroelectric development did not go into service until 1895, when the first Niagara Falls plant began operating. In the fall of 1902, construction began on the first large hydroelectric station in Connecticut. Several hydroelectric plants were built on the Housatonic river—but unlike the Niagara River, with its large drainage area and the regulatory effect of the Great Lakes, the Housatonic had a very irregular flow, varying considerably from season to season and year to year. To firm up existing and proposed hydro capacity on the river, some natural or artificial means for regulation of the river was needed. Rocky River seemed to be the answer.

The Rocky River Plant had two reversible pumps that somewhat resemble large hydroelectric turbines. This permitted significant improvements in the system efficiency of the company's network of hydroelectric and thermal-electric power generating plants. Water is pumped uphill through a penstock and stored in Lake Candlewood. When demand reaches a peak, water is released through the same penstock, and the motors driving the pumps reverse to become generators to produce electricity. The original penstock, built in 1927, was restored in 1963. See ASME website for more information