In a statement to the Stock Exchange, National Power said it was "in discussions" with Union de Fenosa about taking a 25 per cent shareholding in Spain's third-largest power group. National Power and rival power company Edison are the two final contestants in the auction, announced by the Spanish government earlier this year. The decision is expected to be announced today.
Analysts estimate that the stake, which would give National Power an interest in 8,000 megawatts of generating capacity, will cost about pounds 400m.
If its bid is successful, National Power intends to use the joint venture as a vehicle for further investments around the world. The company has already invested pounds 1.3bn in electricity assets, giving it exposure to a total capacity of 12,000MW.
National Power shares closed down 13p at 515p.