Ireland is still overwhelmingly reliant on fossil fuels for power, heat and transport despite the climate and cost impacts, latest data shows.
Almost 80 per cent of all the energy used by homes, businesses, industry and travel came from oil, gas or solid fuels, the figures for 2025 show.
The country now has the third lowest share of renewable energy in the European Union, the report from the Sustainable Energy Authority of Ireland (SEAI) shows.
Growing traffic, increasing flights and data centre expansion are all complicating efforts to move away from the carbon-polluting fuels, it says.
It forecasts that overall energy demand will increase by 10 per cent by 2030 – driven largely by these sectors.
The trend is the opposite of what is required under 2030 energy efficiency and climate targets.
Ireland is already using 15 per cent more energy than those targets allow and the gap is set to widen.
High dependence on fossil fuels not only makes meeting the country’s climate action commitments hard to meet but also costs consumers dearly, the SEAI says.
That is because almost all fossil fuels have to be imported at prices set by markets over which Ireland has no control.
“We’ve seen this year how a secure and affordable energy supply is central to the financial health of our households, the livelihoods of so many of our citizens, and the strength of our economy,” said SEAI chief executive, William Walsh.
“We simply can’t take it for granted any more. With so many worried about their bills this winter, we must reduce our reliance on imported, polluting fuels. It’s the only long-term solution.”
Fossil fuels provided 79.1 per cent of the country’s energy last year which was a small reduction on the 81.4 per cent in 2024.
Emissions from energy also fell last year, by 3.6 per cent, with a further fall provisionally recorded in the first half of this year.
However, those reductions were partly due to an increase in the amount of electricity imported from Britain as Ireland does not have to count the energy usage or emissions associated with the generation of electricity overseas.
A total of 16.3 per cent of the electricity used in Ireland last year was imported compared to 14 per cent the previous year.
The supply of renewable electricity within Ireland is growing but slowly and in circumstances where demand keeps rising.
Gas remained the largest source of electricity generation, accounting for 40 per cent of the total, while wind, the biggest renewable source, provided 32 per cent.
Transport stands out as the sector most dependent on fossil fuels, with 92 per cent of all travel fuelled by petrol and diesel and just 8 per cent by biofuels or electricity.
Despite an increase in sales of electric vehicles, the roads remain dominated by internal combustion engines.
Increased flying is also adding to demand with aviation fuel usage up almost 11 per cent in the first six months of this year, but more private cars and goods vehicles are also on the road.
Data centres used 22.5 per cent of all electricity last year and account for 78 per cent of increase in Ireland’s electricity demand between 2015 and 2025.
William Walsh said while more renewables, more energy storage and more efficient energy use would help, policy decisions also needed to be taken.
“Decisions on the scale and location of major energy users, including large new electricity demands, such as data centres, must also be considered through the lens of energy security, affordability and climate objectives,” he said.