Ireland's government announced last year that it would sell state assets as part of its EU/IMF bailout, including generating capacity at ESB, the retail marketing and services arm of gas utility Bord Gais and a 25 percent stake in airline Aer Lingus .

The ESB is to sell a 50 percent shareholding in Britain's Marchwood Power, which owns an 840 megawatt power station near Southampton and is jointly owned with Scottish & Southern Energy, it said in a statement.

It will also sell 50 percent of Spain's Bizkaia Energia, which owns a 755 megawatt power station near Bilbao and is jointly owned by Japan's Osaka Gas.

ESB did not say how much it expected to earn from the two sales.