British Energy Group Plc, whose nuclear reactors can produce about a fifth of the U.K.'s electricity, plans to extend the use of its Hinkley Point B and Hunterston B power stations by five years.

The two plants will be kept in service until 2016 at an additional cost of at least 90 million pounds ($185 million), the Livingston, Scotland-based company said in a statement today.

British Energy is seeking to upgrade the plants' operating capacity to 70 percent from 60 percent, and will consider raising that rate further. At 70 percent capacity, the extension project is viable with electricity prices at 27 pounds a megawatt-hour, the utility said.

Spending on maintenance and improvements at British Energy's power stations, excluding Hinkley Point B and Hunterston B, will total 190 million to 210 million pounds in the financial year 2007 to 2008, the company said. Spending on its ``fleet'' next year will be between 200 million and 215 million pounds, it said.

British Energy reported a 44 percent decline in fiscal second- quarter profit Nov. 13, amid disruptions at its Heysham-1 and Hartlepool plants, which remain shut indefinitely for repairs. Inspections have since revealed three worn wires at its stations.

Extending the life of the two facilities ``is important in supporting the U.K.'s climate change goals for the reduction of CO2 emissions,'' Chief Executive Officer Bill Coley said in the statement. The U.K. government is planning legislation to help cut emissions of the gas at least 60 percent by 2050.

British Energy's rose as much 4.5 pence, or 1 percent, to 533 pence and was trading at 532.5 pence as of 8:03 a.m. London time. The company's shares have declined 2 percent this year, valuing the company at 5.5 billion pounds.