SSE Airtricity is to increase its standard variable electricity prices by 9.5% from next month, which will add around €150 annually onto a typical customer's bill.
This is the supplier’s second price increase this year, after it hiked electricity prices by 10.5% and gas prices by 8.4% in April.
The result of this means nearly half of SSE Airtricity’s 460,000 electricity customers in Ireland will be hit by a cumulative rise in their bills of 20% this year alone.
There will be no price increase for its gas customers.
The company said the price increase, which will take effect on 20 October, is due to increased network and system operator charges, as well as what it said is "ongoing wholesale volatility and the "higher cost of doing business".
Minister for Public Expenditure Jack Chambers has again insisted there "won't be" a one-off cost-of-living package in the upcoming Budget.
Mr Chambers said the Government instead plans to use the social protection system to "better and best support families and workers through targeted interventions".
"We'll be considering that in the context of Budget 2026, how we can use the social protection system to support the lowest income families."
"We need to ensure we manage the economy in a sustainable way, and that's why it's not possible to have a cost-of-living package again this year," he added.
"I know energy costs are putting many families under real pressure, and it is of concern to everyone across the country," Minister Chambers said.
"That's why, through the different interventions we can make through the social protection system, we want to best support people in a targeted way."
Today’s price rise follows similar moves from most of the other main energy suppliers.
Earlier this month Bord Gáis Energy, Energia, and Pinergy all announced similar price increases for their electricity customers.
While last month Flogas also increased its prices.
However, Electric Ireland, which has by far the most electricity customers in the Irish market, said it was not increasing tariffs for them ahead of the winter - while it lowered gas prices by 4%.
Commenting on its price rise, Managing Director of SSE Airtricity Stephen Gallagher said: "We know this news will be disappointing for customers, increasing our prices is always a last resort.
"We would encourage anyone concerned about their energy costs to contact us, and we will work with them to find a solution together.
"We have payment plans, offers and tariffs in place to support customers this winter."
Mr Gallagher added that "while investment in the grid is necessary, these regulatory network charges are outside of our control and come at a time of continued wholesale volatility which is leading to higher cost of doing business".
Consumers are advised to shop around to try and offset the cost of some of the substantial energy-price increases announced recently.
SSE Airtricity is owned by the British utility company SSE, which recorded an operating profit of £2.42 billion (c. €2.78 billion) in the year to March.
While SSE Airtricity, which supplies energy customers on the island of Ireland, had an operating profit of £94.5 million (c. €108.5 million) for the 12 months to March 2024.
