RWE npower, the German utility, will unveil plans today to spend £800 million on one of the biggest gas-fired power plants to be built in Britain.

The state-of-the-art combined cycle gas turbine (CCGT) power station is designed to produce electricity for nearly four million homes. It is the third big project to be announced in the industry in six months and could lead to the creation of hundreds of jobs.

RWE npower hopes that the new plant will help to win over environmentalists, who staged a high-profile climate change protest at one of its oldest sites, the coal-fired Didcot A, last year.

CCGT is regarded as greener than coal because it produces only 0.4 tonnes of carbon per kilowatt hour against 0.9 tonnes in existing coal-fired plants.

The new power station will be built on the site of former coal and oil-fired plants, either in Pembroke, West Wales, or in Staythorpe, Nottingham-shire. Pembroke would be a 2,000megawatt project, making it the biggest in the UK. Staythorpe would be 1,500MW.

Construction is expected to begin this year, with generation starting in 2009. The project is part of a move to expand RWE npower’s generating capacity in Britain by 2,100MW, an increase of 23 per cent.

The company is also spending £100 million on the development of two wind farms, in Knabs Ridge, North Yorkshire, and in Little Cheyne Court, on Romney Marsh, Kent.

Andrew Duff, the chief executive of RWE npower, said that the CCGT plant, to be built by Alstom, a French construction company, would help to tackle CO2 emissions and change Britain’s “power-generation mix”.

However, he indicated that the generator would stick by coal-fired plants in the future, despite growing opposition to coal from Greenpeace and other environmental campaigners.

Greenpeace withdrew its support for npower’s “green” electricity product Juice — which is backed by David Cameron, the Conservative leader — last August in a dispute over emissions.

Mr Duff said: “Around a third of the UK’s coal-fired power stations are set to close over the next five to ten years. To maintain secure electricity supplies, we will need to replace some of these with more efficient coal plants, and look at ways of tackling carbon-dioxide emissions from coal-fired generation.”

RWE npower’s decision reflects a growing confidence in the industry over the “rules of engagement” on Britain’s future energy strategy.

A Government White Paper expected to be published at the end of March is likely to promote the need for a diverse energy mix and lay out guide-lines over the roles for clean-coal and nuclear stations.

Centrica promised before Christmas to build Britain’s cleanest coal-fired power station in a £1 billion development on Teesside. Its is also building a gas-fired plant at Langage, near Plymouth, Devon. Scottish and Southern Energy plans a £400 million gas-fired power plant in Marchwood, near Southamp-ton. E.ON is thought to have been looking at cleaning up a gas-fired station in Killing-holme, Lincolnshire, but wants backing from the Government.

RWE npower portfolio

Didcot A, commissioned 1972, coal, capacity 1,940MW

Aberthaw, 1971, coal, 1,455MW

Didcot B, 1996, CCGT, 1,370MW

Tilbury, 1968, coal, 1,020MW

Littlebrook, 1982, oil, 1,000MW

Little Barford, 1994, CCGT, 680MW

Fawley, 1969, oil, 500MW

Great Yarmouth, 2002, CCGT, 420MW

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