The 10-year investment plan includes $500 million to upgrade power stations in 2004-2013, and an earlier decided outlay of $200 million to improve the safety of its hydropower dams in 2002-2007.

A spokesman for Vattenfall said: “This investment decision will contribute strongly to the secure supply of electricity in the Nordic region where hydropower plays an important role.” Kjell Isaksson, head of Vattenfall’s hydropower division, said the investments would only marginally increase power generating capacity through increased efficiencies. He said over 30 units were included in the upgrade plan.

Vattenfall said that many of its hydropower plants were put on stream during the 1950s and 1960s, and so some of the mechanical and electrical equipment at those plants were reaching the end of their estimated 50-year lifespan.

Vattenfall said that it would finance this investment plan out of income from operations.