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Completion Date
Project Type
Power Generation
Shannon, Ireland
52 42 20.0 N
8 36 46.0 W


By international standards, the Shannon Hydroelectric Scheme for the electrification of the Irish Free State was one of the largest civil engineering projects at the time it was built.

Shannon Hydroelectric Scheme
Upon independence, the Irish Free State started an ambitious program of redevelopment. A major objective was to find a way to provide cheap, reliable, and plenty of electricity. Dr. Thomas MacLaughlin, who had joined German engineering firm Siemens Schukert in Berlin in 1922, raised the idea of the Shannon scheme. He persuaded the Irish government to construct a single hydroelectric station at Ardnacrusha which would power a national electric grid, and enable rural electrification. The contract for the entire work was given to Siemens Schukert.


The works involved the diversion of 90% of the Shannon into a head race canal 7.5 m long by which the water was delivered to Ardnacrusha, where a fall of 34 m was available. After passing through the generators at the power station the spent water was conveyed back to the Shannon by means of a tail race canal. The civil engineering achievements include the removal of 7.6 million cubic meters of earth and 1.2 million cubic meters of rock, the building of a 96.6 km purpose built narrow gauge railway, the construction of four major bridges and the diversion of nine rivers and countless streams. The chief Civil Engineer on the project was Frank Sharman Rishworth from Tuam, who was at the time Professor of Civil Engineering at University College, Galway, a National University of Ireland. When the scheme was completed, it was turned over to the Electric Supply Board (ESB).

By international standards the Shannon scheme for the electrification of the Irish Free State was one of the largest civil and engineering projects at the time it was built. It created an essential framework and platform for the social, economic and industrial development of the country.


  1. The Shannon Hydro-Electric Scheme , T. G. Carroll & Sons: Limerick, 1929.
  2. Shiel, Michael J. The Quiet Revolution: the Electrification of Rural Ireland, 1946-1976 , Dublin: O'Brien Press, 1984.