In 2025 gas met 40.2% of Ireland's electricity demand (Ember, incl. imports), wind 32.7%, net imports 16.4% and solar 3.1%. As a share of domestic generation only, gas was 48% and wind 39.1%. Since 2020, data centres account for 85% of demand growth, met mostly by imports (Ember, Oct 2026).
Gas made 40.2% of demand, wind 32.7% and net imports 16.4%; data centres used 22.1% of total demand (23.2% of metered electricity, the CSO's own measure).
The left side splits Ireland's 34.6 TWh of electricity demand in 2025 by where it came from: gas 13.9 TWh, wind 11.3 TWh, net imports 5.7 TWh, solar 1.1 TWh and smaller amounts of coal, oil, hydro and bioenergy. The right side shows data centres' metered use, 7.7 TWh (CSO), against everything else; as a share of Ember's demand, which includes network losses and unmetered use, that is 22.1%, a little below the CSO's share of metered electricity. Electricity is pooled on the grid, so no source can be traced to any one user; the two sides are set side by side, not matched. This is the Republic only, on Ember's annual basis; EirGrid's operational data used in the Imports section gives slightly different import totals and shares. Imports arrive through the two cables to Wales and the North–South line, and the cables run near their limit much of the time.
Demand rose 5.4 TWh, data centres alone 4.6 TWh. Imports rose 6.2 TWh, more than the whole increase, while Irish gas generation fell.
Each bar is the change in one source of Ireland's electricity between 2020 and 2025, stacked so that they add up to the change in demand (5.43 TWh). Net imports rose 6.19 TWh, gas fell 1.07 TWh and wind grew only 0.24 TWh, so the extra demand was met by net imports (the cables to Wales and the North–South line) rather than by new Irish generation. Data centres' metered use grew 4.63 TWh over the same years, 85.3% of Ember's demand change (78.1% of the growth in all CSO metered electricity); the two are set side by side, not matched. Over the longer run, 2015 to 2025, wind added 4.78 TWh and imports 5.01 TWh.
Ember yearly electricity data (CC BY 4.0), 2026-10-03. Share of demand divides by demand (34.6 TWh), which includes net imports. Share of domestic generation divides by electricity made in Ireland (28.9 TWh). Gas Networks Ireland and the CSO quote about 40% of supply.
The fuel mix since 2015
40.2%
Of demand met by gas, 2025
wind 32.7% · imports 16.4%
85%
Of demand growth 2020–2025 was data centres
4.63 of 5.43 TWh
+768 MW
More imported at the overnight floor than in 2019
from exporting 176 MW
-1,010 MW
Capacity shortfall, 2026 (base case)
EirGrid adequacy, before emergency measures
The new demand ran on imports. Between 2020 and 2025, data centres were 85% of the growth in Irish electricity demand. Net imports rose 6.19 TWh while Irish wind added only 0.24 TWh and gas fell. At night, when data centres are a bigger share of load, Ireland went from exporting to importing ~592 MW.
Since 2015: Irish demand rose 30% (28.82 → 37.4 TWh). Since 2020 wind's share has stayed between 31% and 38% and gas's near 48%; the growth was met by net imports, up from -0.5% to 16.4% of demand.
Because they divide by different totals. Ember's 40.2% is of demand, which includes net imports; 48% is of electricity generated in Ireland. Gas Networks Ireland and the CSO report about 40% of supply. Always check the basis.