ESB has completed the acquisition of Northern Ireland's electricity network NIE from the Viridian Group for £1.2 billion.
As part of the acquisition, ESB has also bought NIE Powerteam Limited and Powerteam Electrical Services (UK) Limited, which provide electrical construction and maintenance services.
In total, the NIE Group employs approximately 1,300 staff.
The ESB and Viridian had competed with each other to supply electricity to commercial and industrial customers throughout Ireland. The electricity markets on both sides of the island were merged in late 2007.
NIE is to continue to operate as a stand-alone business under the NIE brand and identity.
The DUP and the Ulster Unionists had previously objected to the deal.
ESB Chief Executive Padraig McManus said: 'We are delighted with the acquisition of NIE, an efficient and successful company. ESB is committed to making the capital investment required to match future growth in the economy and to meet the Northern Ireland government's targets in relation to the development of renewable energy'.
