A quarter of all electricity used in Ireland was generated from renewable energy sources last year.
That helped avoid three million tonnes of fossil-fuel related CO2 emissions, according to latest figures from the Sustainable Energy Authority of Ireland (SEAI).
It was the second largest source of electricity in 2015 behind gas and ahead of coal.
More than 80% of green power came from wind turbines while the rest came from a range of technologies including hydropower, biomass, waste and landfill gas.
Dr Eimear Cotter, SEAI Head of Low Carbon Technologies said: “Ireland is making significant progress in decarbonising our electricity system.
“We know that renewables in electricity generation helps to lower CO2 emissions but we still have an electricity system that is heavily reliant on carbon emitting fossil fuels. With 2020 renewable electricity targets approaching, we need to intensify action to increase the contribution of all renewables in our electricity mix.”