Energy provider Iberdrola has become the latest in the Irish market to increase its prices.
The company is putting up what it charges for electricity by 17.5% and for gas by 18%.
The changes will add €18.09 to the average monthly electricity bill and €12.81 to the average monthly gas bill.
The increases, Iberdrola's third this year, will take effect from October 1.
Iberdrola has blamed the significant rise in global wholesale cost of energy as well as ongoing issue with Ireland’s power grid.
"While we always try to keep prices as low as possible, we’ve seen rocketing wholesale energy prices in recent months," said Sean O’Loughlin, Head of Iberdrola Ireland.
"As a result, we need to amend our prices to reflect these rising costs."
"We’re in the process of contacting our customers to advise them of these price changes and – as always – will continue to do what we can to support them."
The Spanish firm added that customers on discounted tariffs for things like paying by direct debit and use of paperless billing will continue to receive their current level of discount.
"There seems to be a crisis in the energy market at present as rapidly increasing prices in the wholesale cost of energy are being passed on to consumers, coupled with a lack of electricity output due to power plants being down," said Darragh Cassidy of Bonkers.ie.
"However price increases of this magnitude and frequency are unsustainable. And coupled with recent concerns about potential power outages and pressure demands on the grid, questions need to be asked about how the market is being managed."
Part of the Iberdrola Group, the company offers 100% green energy tariffs and entered the Irish market two years ago.
In 1997, ScottishPower built one of the first windfarms in Ireland in Barnesmore in Donegal and now operates six windfarms across the north and south of Ireland.