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Shannon Hydro Scheme

Ardnacrusha, Co. Clare, Ireland




4 years


£5.2m (£290m today)


Co. Clare, Ireland
Project achievements

Economy boosted

Electricity meant social infrastructure was improved along with people’s job prospects.

Solved the problem

Used the power of river water diverted into hydro electric generator. Previous

Used engineering skill

Devise a way of providing electricity for the first time in Ireland.

Generate power for Ireland using hydro-electricity

The Shannon Hydro Scheme marked the beginning of the electrification of Ireland. It harnessed the power of the river Shannon and led to the setting up of the country's Electricity Supply Board.

The scheme was the brainchild of Irish engineer Thomas McLaughlin, who worked for the German firm Siemens Schukert in Berlin. He persuaded the Irish government to build a single power station near the village of Ardnacrusha on the banks of the Shannon.

His plan diverted the river down a man-made canal to a waterfall that would drive the power station's turbines.

At the time, the scheme was one of the largest civil engineering projects in the world.

Shannon Hydro Scheme

The Shannon hydro scheme marked the beginning of the electrification of Ireland. It harnessed the power of the River Shannon and led to the setting up of the country’s Electricity Supply Board.

Did you know …

  1. The first 3 months of the project saw 3 freighters and 87 steamers deliver more than 30,000 tonnes of equipment to nearby Limerick.

  2. Engineers built over 60 miles of railway to get materials to the project sites. 130 steam locomotives, 8 electric locomotives and 1,770 railway wagons ran on the line.

  3. Workers dug up 7.5m m3 of earth and 1.25m m3 of rock during construction.

  4. In 2002 the American Society of Civil Engineers designated the power station as an Engineering Milestone of the 20th century.

Difference hydro-electricity has made

The Shannon Hydro Scheme brought a reliable supply of electricity to much of Ireland which speeded up the country's commercial and industrial development.

Easier access to electricity led to significant improvements in the quality of life for people living in the cities and countryside alike.

The scheme is also credited with reducing emigration – an improved national infrastructure meant businesses in Ireland could create more jobs.

How the hydro scheme was built

Preliminary work saw engineers construct a temporary, diesel-powered power station to drive plant and equipment for the project.

They also built tool-making and welding shops, along with huts to accommodate the project workforce. The scheme had 5,000 workers at its height, many of them from Germany.

One of the first areas of work was for engineers to build a weir across the Shannon to divert water into the head-race canal. A 'head-race' is a channel that feeds water into a mill or turbine.

The head-race canal built for the scheme was 8 miles long. As it cut through several roads, engineers had to build 3 concrete bridges across it – at O'Brien's Bridge, Blackwater and Clonlara.

The power station itself was built at Ardnacrusha at the end of the canal.

Workers dug out 200,000m3 of earth and 150,000m3 of rock during the station's construction.

The Shannon Hydro Scheme started generating on the 29 October 1929. By 1935 it was producing 80% of Ireland's electricity.

People who made it happen

  • Commissioners: Government of the Irish Free State
  • Scheme designer: Thomas McLaughlin
  • Chief civil engineer: Frank Sharman Rishworth
  • Contractors: Siemens Schukert