Government plans to generate 30 per cent of UK electricity from renewable sources by 2020 are doomed to failure, according to the chief executive of one of the world’s biggest utility companies.

Wulf Bernotat, chief executive of E.ON, said that British politicians needed to stop misleading the public about what was achievable.

He said that British plans to build 33 gigawatts of offshore wind power, up from 0.6 gigawatts at present, was impossible, given the necessary investment and relatively short timeframe. “Politicians need to be more realistic,” he said. “If you just set out these targets without really taking the effort to square it with industry, then you end up with the dilemma of it not being achievable.”

E.ON, which reported 2008 revenues of €87 billion (£79 billion), more than any of its peers, plans to spend €10 billion a year globally on new power-generating equipment, including nuclear power plants, wind farms, gas and coal plants. It has invested about £930 million in Britain this year and is a key partner in London Array, a £3 billion project to build the world’s largest offshore wind farm in the Thames Estuary.

Mr Bernotat said that there was a bigger mismatch between government targets and what was achievable in Britain than in E.ON’s other key European markets, including its home market. “Germany started earlier and there is a bigger base to build on,” he said. “It’s not a question of willingness. Targets have to be ambitious but the expectation level should be realistic.” E.ON, which employs 88,000 people, has eight million customers in Britain through its UK subsidiary. Its ten coal, gas and oil-fired power stations generate about 10 per cent of the UK’s electricity.

A spokesman for the Department of Energy and Climate Change said: “We must clean up our energy supplies to meet our climate change goals and that will mean a massive expansion of renewable energy. Our target is ambitious but we have a strategy to meet it by 2020.”

Times Recommends

• Minister in talks with Saudis to protect creditors
• Premier Inn hits back in £29-a-room row
• Bankers hit back at 'populist' bonus supertax