ESB has announced that it will buy the Northern Ireland Electricity networks business from Viridian for €1.2 billion.
The purchase also covers associated businesses which provide electrical construction and maintenance services.
The NIE Group employs 1,300 staff and is owned by the Viridian Group which runs the generation and supply business Energia, and operates windfarms and the Huntstown power station in north Dublin.
The €1.2 billion deal will see NIE continue to operate under its own brand, but ESB says the link will help both the Irish and Northern Irish governments to hit their policy and environmental objectives in developing renewable generation and smart metering, and ensuring security of supply.
Over the past ten years ESB has spent €6 billion on refurbishing the Republic's energy infrastructure, and ESB chief executive Padraig McManus says this acquisition shows the company's ambition to expand its business in the changing Irish energy sector.
The deal still has to be cleared by both Irish and British competition authorities, but it is expected to be complete by the end of this year.
