Lester Allen Pelton was the first person to invent a hydroelectric engine, which utilized hydroelectric power. His invention was called the Pelton wheel and came about while Pelton was working to improve turbine water wheels commonly used in mining operations during California's gold rush.
At the time, many mines required steam engines, which used large amounts of coal and wood. While watching a spinning water turbine, Pelton noted that if the water hit the side of the turbine, the wheel spun faster. He also noted that there were numerous fast-flowing creeks and waterfalls that could be used to turn the turbine. In the 1870's he began work on his invention, installing the first working model at the Mayflower mine in Nevada City, Calif., in 1878.