Ed Miliband’s offshore wind farm blitz could add up to £1.8 billion a year in green levies to energy bills.

Ministers on Wednesday announced the biggest ever expansion of offshore wind farms in the UK through subsidy contracts.

The Energy Secretary said the hundreds of new turbines were “a monumental step towards clean power by 2030” and would be significantly cheaper than the alternative of building gas plants.

The government estimated that levies on electricity bills to fund the wind farms could reach almost £1.8 billion a year when they start generating, expected by 2030.

But the sector said this would be largely offset savings from the wind farms lowering wholesale power prices.

The wind farms have a capacity of 8.4 gigawatts, enough to power the equivalent of more than 12 million homes.

Claire Coutinho MP, Shadow Energy Secretary, said: “Labour promised to cut people’s energy bills by £300, but Ed Miliband has just locked every family in Britain into higher energy bills for decades. These are the highest prices for offshore wind in a decade and higher than the current cost of electricity. If you think your bills are too high, this won’t make them any lower. 

“Bills are now almost £200 higher than when Labour came to power and Ed Miliband is cementing our uncompetitive electricity prices for even longer at a time when the world is becoming more unstable and we need cheap, reliable energy to compete.”

The developers have been given contracts guaranteeing that households and businesses will pay a fixed price for the power they generate for 20 years. 

The majority of the contracts have been awarded to German energy company RWE.

Mr Miliband has set a target of 95% clean power generation by 2030 despite other political parties and critics arguing this is unfeasible.

The projects approved on Wednesday are regarded as the last batch that can reliably be built in time to contribute to the goal, although it is possible some due to be built under contracts awarded later in the year will also be finished .

Mr Miliband said:  “With these results, Britain is taking back control of our energy sovereignty.

“This is a historic win for those who want Britain to stand on our own two feet, controlling our own energy rather than depending on markets controlled by petrostates and dictators.”