Provisional figures from EirGrid show that renewable sources delivered 49% of Ireland's electricity in March, broadly matching February's 48% share.

Wind was the main contributor, accounting for 40% of the overall fuel mix. Total wind generation reached 1,258 GWh (gigawatt hours) during the month.

Overall system demand in March was 3,142 GWh, up from 3,027 GWh in February.

Early spring sunshine and the expanding fleet of grid-connected solar farms set a series of solar milestones. On 21 March, grid-scale solar output peaked at 983.46 MW, approaching 1 GW — enough to supply roughly 500,000 customers. That surpassed earlier highs of 979 MW on 19 March and 950 MW on 6 March.

These records reflect only grid-scale solar and exclude embedded rooftop systems on homes, businesses and farms. When rooftop solar is factored in, EirGrid's National Control Centre has observed notable shifts in demand patterns.

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On bright days, daytime demand for electricity from large generators drops as premises meet a greater share of their own needs from embedded solar. For example, in the early afternoon of Thursday 19 March, demand was 974 MW lower than the previous Thursday (12 March) — largely due to higher levels of rooftop solar output in better weather. EirGrid is also seeing days when early afternoon demand falls below night-time levels, again influenced substantially by embedded solar.

EirGrid's National Control Centre continually balances solar, wind and conventional generation to ensure demand is met safely and reliably.

Charlie McGee, EirGrid's System Operational Manager, said: "While solar power is currently a relatively small component of the overall fuel mix across a month, these record peaks demonstrate its ever-increasing importance as a source of renewable energy in Ireland as we work towards a more sustainable and renewable ready electricity grid.

"Looking in particular at the instantaneous power that grid-scale solar can provide, it can meet over 20% of demand at times.

"It's also interesting to see how much of an impact rooftop solar is having on overall system demand. On brighter days less of Ireland's electricity needs are now served by large scale grid connected generation. This is helping to further reduce our reliance on non-renewable sources of electricity."