For the second month in a row, battery discharge reached a record 396 MW in the Irish transmission system in December 2025.
According to the latest data from the state transmission system operator (TSO) EirGrid, this record was set on Monday, December 15. surpassing last month’s record of 362 MWset on November 25.
This latest album comes as Ireland opened its wholesale market to battery storageunder a new scheduling and shipping program last November.
Overall, renewable energy sources were responsible for 43.8% of electricity generation on the Irish grid in December. Most of the renewable energy generation came from wind energy, at 38.5%, almost four percentage points more than the previous month, while solar energy accounted for 0.5%.
Even though the share of solar energy decreased during the winter season, this was the case in 2025 a record year for solar energy systems in Ireland. According to data from the Sustainable Energy Authority of Ireland (SEAI), a record 34,0888 households installed solar panels last year, an increase of 16% on the previous year.
On Christmas Day, as peak demand shifted from evening to lunchtime – as ovens and other appliances were turned on to prepare dinner – renewable energy sources met 55% of the day’s electricity demand.
This was not the case on New Year’s Eve as the festivities took place late into the evening and night. Therefore, there was no shift in peak energy demand, which was more in line with what is observed during most other evenings in winter.
Diarmaid Gillespie, Director of System Operations at EirGrid, said: “Similar to what we have seen in recent months, December was another strong month for renewables, with us once again seeing a significant amount of wind generation contributing to the overall fuel mix for the month.”
