On July 13, 1895, electricity generated here and transmitted to Sacramento marked the beginning of a nationwide change in how homes were lit and civilization was powered. As the first hydroelectric power plant of its kind in Northern California, the project extended over two miles and used the force of water and new Alternating Current technology to generate enough electricity to power an entire city. The electricity was sent an unprecedented 22 miles to Sacramento, where it powered city lights and a fleet of electric trolleys. This achievement depended on a cut stone dam two miles upriver that diverted water into a canal running parallel to the American River and delivering it to a hydroelectric powerhouse. Because the river dropped significantly past Folsom, the canal kept the water almost level and preserved its potential kinetic energy for use at the powerhouse. Prisoners from adjacent Folsom Prison quarried all the rock and provided the labor to build the dam and canal, and they also cut the stone for the powerhouse foundation. The brick for the powerhouse came from nearby Sacramento Valley Railroad buildings that had been dismantled. At this end of the canal, water from the forebay above the powerhouse dropped 55 feet through large penstock pipes into the powerhouse. Each penstock pipe supplied water to spin paired turbines that rotated Alternating Current electrical generators. Together, the four turbine generator sets could produce 3,000 kilowatts of power at 800 volts, or the equivalent of 4,022 horsepower. To improve long-distance transmission efficiency, nearby transformers raised the voltage to 11,000 volts. Because of drought conditions and low river levels, a lower powerhouse was added in 1897 to use the energy available from water discharged by the main powerhouse.