Some 1.2 million electricity customers will see their bills fall for 6% this summer, after Electric Ireland announced the cut today.
The typical saving will be about €57.75 (including VAT) or 5.2 % per year on an average customer bill.
Executive director of Electric Ireland Jim Dollard said: "It means the average annual residential bill for our customers will have reduced by more than €100 over the last 19 months."
Electric Ireland introduced a 2.5% decrease in its gas prices for homeowners and small business customers in January.
The company's parent company ESB recently reported operating profits of €630m for last year.