Ireland’s electricity in winter: more demand, and more of it from wind

EirGrid's monthly figures show that Ireland uses far more electricity in winter than in summer, sets its demand records on cold evenings, and gets a bigger share of its power from wind.

Winter electricity is greener than summer electricity

It may seem odd, but Ireland's electricity is usually cleaner in winter. In February 2026, wind farms supplied 41% of all the electricity used. In August 2026, they supplied just 18%, according to EirGrid, the company that runs the national grid.

Wind farms produce much more in the winter months. Across December 2025, January 2026 and February 2026, renewables supplied an average of about 44% of electricity each month. Across June, July and August 2026, the average was about 34%, even with record solar output.

Ireland uses about a fifth more power in winter

Demand is measured in gigawatt hours (GWh). One GWh is a million kilowatt hours, the unit on a household bill. January 2026 was the busiest month in the past year, with 3,409 GWh of demand, 27% more than June 2026.

From December 2025 to February 2026, demand added up to 9,670 GWh. From June to August 2026, it was 8,216 GWh. That makes winter about 18% higher, an Irish Wire calculation from EirGrid's monthly figures.

Summer has its own pattern. Grid-scale solar produced 692 GWh across summer 2026, up 58% on summer 2025. But with wind at only 18% in August 2026, gas supplied 42% and imports 26%, the highest import share of the six months above.

The record is over 6,000 MW, set on a cold January evening

Peak demand is the most electricity used at any one moment, measured in megawatts (MW). It matters because the grid must have enough power stations, batteries and imports ready for that moment. Ireland's record is 6,024 MW, set at 5.47pm on 8 January 2025, during a cold spell.

Demand first passed 5,000 MW in the cold snap of December 2010, EirGrid says. That record stood for 10 years. Peaks then rose by almost 900 MW between late 2020 and January 2025.

“The extended cold spell this week saw electricity demand reach record highs.”Diarmaid Gillespie, Director of System Operations, EirGrid, news release, 10 January 2025

When the wind drops, gas and imports fill the gap

At the record peak on 8 January 2025, about 60% of electricity came from gas and 17% from renewables. Imports through undersea cables, called interconnectors, supplied 6.6%. Cold, still evenings are the hardest test for the grid.

Gas is still the largest single source in most months. It supplied 44% of electricity in January 2026 and 37% in February 2026, when it was windier. Imports met 16% of demand in January 2026 and 14% in February.

• Demand usually peaks between 5pm and 6pm on winter evenings, EirGrid says.
• On Christmas Day 2025, the peak moved to about 2.15pm, around lunchtime.
• On 31 December 2025, the peak came at 5.15pm, like most winter evenings.
• Batteries set a new record on 15 December 2025, discharging 396 MW.

Where December's electricity came from

December 2025 used 3,234 GWh, up 4% on December 2024. Renewables supplied 44%, a little less than the 46.7% of December 2024. Imports rose from 12% to 17% of demand.

Winter 2025/26 also set smaller records. Demand reached 5,144 MW on Sunday 30 November 2025, a Sunday record, then 5,480 MW on Sunday 4 January 2026. On Saturday 14 February 2026, wind farms produced 3,898 MW at 5.50pm, a new all-time wind record, and demand hit a Saturday record of 5,408 MW.

Data centres use more than all urban homes

The CSO measures all the electricity used through meters each year. In 2025, Ireland used 32,986 GWh, up 3.4% on 2024. Data centres used 7,663 GWh, or 23% of the total, up from 5% in 2015.

For comparison, urban households used 18% of metered electricity and rural households 9%. A typical home's use is highest in winter: the median household used 907 kWh in the first quarter of 2025, against 625 kWh from July to September.

For winter 2025/26, EirGrid's Winter Outlook gave a median forecast peak of 6,044 MW. It said the risk of not having enough generation was much lower than in recent years.