Portuguese renewable energy company Greenvolt Group and Waterford-based Enerpower are set to create 100 new jobs.
It comes as the two companies announced plans to drive forward energy targets here and across Europe.
The companies will install around 500MW of renewable energy in the next five years - enough to power the city of Dublin.
They will also look towards the UK renewables market.
"Today marks the next step in our bold expansion plans and Ireland is a key energy market that will enable us to achieve this," said João Manso Neto, Greenvolt Group's CEO.
"Enerpower has an ambition that matches our own, with already internationally renowned clients, and now have a strengthened capacity to take advantage of the numerous opportunities in Ireland and in the UK," he added.
Owen Power, CEO of Enerpower said this partnership marks a significant step forward for the sustainable energy sector.
"Our collaboration with Greenvolt Group will also drive innovation and speed up the transition towards a more sustainable and eco-friendly energy landscape."
Last year, Greenvolt Group purchased a 51% stake in Enerpower.
