According to EirGrid, the operator and developer of Ireland's electricity grid, renewable sources accounted for 43% of electricity in September. This marked a significant increase on August's 29% share.

Wind was the dominant contributor, providing 36% of all electricity used last month. Total wind generation reached 1,015 GWh.

Grid-scale solar contributed about 5% of generation in the month. Gas supplied 37% of electricity demand, while 19% was met by imports via interconnection.

Overall electricity system demand was 2,857 GWh in September, up from 2,796 GWh in August.

EirGrid balances supply and demand in real time from the National Control Centre and also plans strategically for Ireland's long-term electricity needs. At present, the grid can accommodate up to 75% of electricity from non-synchronous renewable sources at any one time — the System Non-Synchronous Penetration (SNSP) limit.

EirGrid's Director of System Operations, Diarmaid Gillespie, said: "As we would expect as this time of year, we saw a notable change to the fuel mix last month. There was a significant increase on the previous months in the amount of wind generated energy, with it contributing 36% to the overall fuel mix.

"Similarly, we saw a decrease in the amount of solar energy. This follows a record-breaking summer for solar energy in Ireland but is nevertheless to be expected as the days get shorter and darker. We do however expect solar power to provide support to the power system during day light hours, even in the winter months."