A disused mine site could be used to house a €650m hydro-electric power station.
The plant would use renewable energy at night time to pump water from an existing reservoir to a new storage facility. The water would be released during the day to drive turbines and produce up to 360MW of power, sufficient for 200,000 homes. A joint venture between Irish and Austrian companies will seek planning permission within two years for the facility, at the abandoned Silvermines site in Co Tipperary.
Austrian technology companies Strabag and Andritz Hydro and Irish construction firm Roadbridge are among the backers of the project, which will result in 400 jobs being created over the four-year construction phase and up to 50 full-time posts thereafter.
The consortium says the project will not only produce renewable electricity, it will also help clean up the site, with water in the existing reservoir to be decontaminated, ending the seepage of harmful minerals into local water tables.
The plans were announced by Environment Minister Alan Kelly, who said it was a "pivotal" moment for north Tipperary and the country.
"For Silvermines, it will transform the mining legacy here from an environmentally hazardous to a positive one, as well as trigger very significant and sustainable investment and employment in the local community," he said. "From a national perspective, it will significantly advance Ireland's transition to a low-carbon economy."
Project director Darren Quinn said the existing reservoir was some 70 metres deep and 400 metres across, and was filled with contaminated water. A new reservoir would be built on the upper mountain, around 300 metres above the existing one, and the power generated would be transmitted to the national grid by way of underground cables, meaning no pylons would be required.
"The 370 acres of land is already secured for the project, it will be leased and purchased subject to planning," he said.
"There's more detailed feasibility work to be done on the project, and consultation with the local community over the next 12 months. We would hope to seek permission within two years."
The turbine generators would be located below the water in the lower reservoir, meaning that little or no noise would be generated during the electricity production process.
The site was previously owned by Macgobar before closing in the early 1990s. A similar pumped storage hydro facility is already operated by the ESB at Turlough Hill in the Wicklow Mountains, which produces 292MW at peak. The project would also allow wind energy to be deployed at night time during periods of less demand.