The entry of Spanish utility Iberdrola to the Irish market is expected to put downward pressure on Irish electricity prices, which still rank above the European average.
Iberdrola will invest €100m in renewable energy and storage projects in Ireland by 2025 as it starts to offer customers power in the country for the first time.
The Spanish utility said it is immediately offering consumers in the Republic 100% clean electricity tariffs as it enters the market with plans to provide electric vehicle chargers and boiler care services later this year.
The Irish operations of Iberdrola, the world’s first major utility to embrace renewable energy more than a decade ago, will be based in Dublin.
Ireland has the fourth most expensive electricity in the EU, but Iberdrola's presence is expected to lower prices.
"Increased competition should mean more choice and lower prices, which can only be good news for hard-pressed energy customers in Ireland who have seen their bills increase hugely over the past two years and who pay among the highest prices for electricity in Europe," said Daragh Cassidy of price comparison website Bonkers.ie.
Mr Cassidy said Iberdrola’s launch of a fixed tariff is also welcome given how volatile energy prices have been in recent times.
"Fixed tariffs are extremely common in other markets like the UK but suppliers in Ireland have been slow to offer them to customers here," he said.
Iberdrola is the leading renewable energy producer in Europe. It is the 11th entrant to the Irish residential energy market, and the first new supplier to enter since Just Energy in 2017.
Iberdrola has an existing presence in Ireland through the operation of six wind farms - via its UK subsidiary Scottish Power - and it also plans to reinvest in those.
The group said its Irish investment will help the Government hit its target of 70% of electricity from renewables by 2030.
“We are well-placed to support the development of Ireland’s low carbon economy. Ireland is already ahead of the curve when it comes to renewables, and we want to play our part in the clean energy future,” said Iberdrola Ireland boss Colin McNeill.