Almost 40% of electricity generated by renewables in May

James Cox

Almost 40 per cent of electricity was generated by renewables last month with May sunshine producing a record amount of solar energy.

Provisional data from EirGrid, the operator and developer of Ireland’s electricity grid, shows that 39 per cent of electricity came from renewable sources in May. This compares to 33 per cent for the same month last year.

May was a significant month for the amount of solar energy on the power system, contributing 7.8 per cent to the overall fuel mix. This compares to 5.7 per cent last month and to 6 per cent in May 2025.

With the sunnier weather, a series of new peaks were set throughout the month with the highest being achieved on Monday, May 25th, where a new peak for grid-scale solar was achieved contributing 1222 MW to Ireland’s electricity mix.

These records follow Ireland reaching a new peak of over 1 GW (gigawatt) of electricity provided by grid-scale solar power for the first time in April.

At 28 per cent, wind energy made up a significant proportion of the total amount of energy generated across the month. Total generation of wind amounted to 784 GWh (Gigawatt hours).

Elsewhere in May, gas generation accounted for 41 per cent of all electricity used and 21 per cent was imported via interconnection.

The overall electricity system demand stood at 2,794 GWh in May, compared to 2,865 GWh in April.

EirGrid’s National Control Centre carries out the complex task of balancing the supply of renewable sources alongside conventional generation sources to ensure that demand can be met.

Significant progress has been made in integrating renewables onto Ireland’s power system. "To date the developments we have made have enabled up to 75 per cent of electricity to be generated from variable renewable sources (eg wind and solar) at any one time and we have a significant work programme underway to increase this to 95 per cent," EirGrid said in a statement.

When there is a significant amount of solar generation on the grid as there was in May, EirGrid is observing days where the demand for electricity is similar in the early afternoon as it is at night. This can largely be explained by embedded (including roof-top) solar generation helping to supply demand.

Diarmaid Gillespie, EirGrid’s director of system operations, said:  “May was another significant month for renewable energy sources powering the electricity system in Ireland. The amount of solar energy was notable once again given the good weather and an increased amount of grid-scale solar on the system.

“With solar power making almost 8 per cent of the overall fuel mix, as well as the peak records set during the month of May, we have seen again just how important it has become as a source of renewable energy.”