Turlough Hill is Ireland's only pumped storage hydroelectricity scheme. The plant was located and built in the mountains of County Wicklow, during the late 1960s and early 1970s, for Electricity Supply Board by a German contractor. The project cost approximately IR£ 20 millon (Punt) at the time, the year the project commenced the Electricity Supply Board investigated a nuclear power option, which would result in the Nuclear Energy Board. For many years groups could visit the site, the project was a major civil engineering and environmental project in Ireland and was built to increase Ireland's electricity generation capacity.
Turlough Hill has four of six generators fitted and can generate 292 megawatts. Like other similar systems, it has a reservoir. In this case, the reservoir is at the top of a hill, which is released when required to produce electricity and filled when an overcapacity of electricity is available. When the order is given, electricity can be available within approximately a minute of startup, this is quite fast especially when considered with conventional sources such as coal, gas and oil which can take hours if not days because of the requirement to heat all machinery to the steam temperature.