The hydro-electric power station at Ardnacrusha on the River Shannon, 6 km N of Limerick, was built in 1925-9 at the same time as the national grid in Ireland. It was the policy of what was then the Free State to make Ireland independent of British sources of energy. The station was built by the German company, Siemens-Schuckertwerke, and its 75th anniversary was marked by an Irish-German interdisciplinary conference. It was for a short time after its completion the largest hydro-electric generating plant in the world, and was capable of supplying the whole of Ireland. It is some measure of the development of the Irish economy that in 2000 its 85 MW output supplied only 3% of national demand. There is a 14 km headrace from the dam at Parteen, powers 3 Francis turbo-generators installed when the plant was built, and a Kaplan turbo-generator of 1934.