Water

The Connecticut Light & Power Company pioneered the use of pumped storage in the United States at this hydroelectric station. First operated in 1929, 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.

This low-head operating plant is representative of nineteenth-century hydropower-plant practice using many small turbines in contrast to twentieth-century use of few large turbines and generators. Its 40,000 horsepower capacity made it the largest in the country using turbines of American design (McCormick-Francis). The contemporary and larger Niagara installation used turbines of French design (Fourneyron). The entrepreneur of this plant was Francis Clergue, a lawyer, who employed as his chief engineer Hans A.E. von Schon, a German immigrant who had served with the U.S.

This run-of-the-river plant is a typical example of late nineteenth-century small-scale (750 kilowatt) low-head hydroelectric power technology. The Fries Manufacturing and Power Company began operating the Idol's Station on April 18, 1898, making it the first commercial hydroelectric plant in North Carolina involving long-distance power transmission, fourteen-miles distance at 10,000 volts. Idol's was an important power source for transportation, lighting, and industry in the Winston-Salem area.