Household gas and electricity bills will rise by up to £249 a year to pay for a seven-fold increase in energy from low-carbon sources by 2020, according to the Government’s Renewable Energy Strategy.

The actual cost per home will depend on how successful the Government is in implementing a series of new measures to improve the energy efficiency of homes and reduce fuel consumption.

Ed Miliband, the Energy and Climate Change Secretary, claimed that these measures would reduce the extra cost to an average of £92 a year per home. He announced only modest extra funding, however, for home insulation and other methods of reducing fuel consumption.

Energy companies are expected to invest £100 billion over the next decade in renewable sources, including wind turbines, solar panels and tidal schemes. Yet the Government is increasing the funding for home energy-saving schemes by only £600 million, or 20 per cent.

A table buried at the back of the 232-page strategy paper states that meeting the Government’s target of increasing the proportion of total electricity from renewable sources from 5.5 per cent to 30 per cent will add £77 — 15 per cent — to the average annual domestic electricity bill by 2020 and £172 — 23 per cent — to the average gas bill.

The press release accompanying the strategy states that the increase in combined household energy bills will be £92, or 8 per cent, by 2020, with prices beginning to rise only in 2015.

Challenged by The Times to explain the discrepancy between the figures, Mr Miliband said that household energy consumption would fall sharply under a range of policies, including installing a smart meter in every home by 2020 to show how much power each appliance was consuming.

He said that every £1 invested in energy efficiency measures, such as home insulation, would be more than recouped by savings in energy bills.

He admitted, however, that more needed to be done to protect low-income households from fuel poverty. The Government would legislate, he said, “at the earliest opportunity” to require energy companies to have cheaper rates for poorer households, particularly “older pensioners on the lowest incomes”. At present companies offer social tariffs on a voluntary basis.

The strategy says that seven million homes will benefit from “pay-as-you-save home energy makeovers”, under which residents would pay in instalments for energy efficiency measures rather than paying in advance.

A separate scheme will subsidise 1.5 million homes that install their own sources of green energy, including solar panels and roof-mounted wind turbines. They will receive payments of up to £800 a year for feeding electricity back into the grid.

Ofgem, the energy regulator, will be given a new responsibility to “protect the future consumer” by reducing carbon emissions, rather than simply focusing on ensuring fair prices. But the body will lose the right to determine access to the grid, with the Government assuming that power to ensure faster access for wind farms.

The strategy includes plans for 10,000 new wind turbines by 2020 — 6,000 on-shore and 4,000 off-shore. This is a substantial increase on the 7,000 figure previously mentioned by ministers. Local authorities will receive £11 million to employ experts who will help to push through applications for wind farms.

Mr Miliband said that increasing the amount of renewable energy would reduce Britain’s dependence on imports of oil and gas from volatile parts of the world. He also published a shortlist of five options for exploiting tidal power in the Severn estuary, including a £21 billion barrage of ten miles from Cardiff to Weston-super-Mare that could produce 5 per cent of Britain’s electricity. A second public consultation on detailed proposals for the Severn will be held next year.

A competition will be held to select 15 towns or villages that will each receive £500,000 to “trial the newest technologies and be beacons for how other communities can cut their carbon emissions”.

A £60 million investment in wave and tidal energy will include £9.5 million for an undersea wave generator off the coast of St Ives in Cornwall.

The amount of biofuel in road transport fuels will be increased from 2.6 per cent at present to 10 per cent by 2020, adding 6 per cent to the cost per litre of petrol and 2 per cent to diesel.

Overall fossil fuel use will fall by 10 per cent by 2020 under the strategy.

Mr Miliband said: “Climate change is the moral issue of our time. In five months, the world must come together at [the UN conference in] Copenhagen and follow through on the commitment of world leaders last week to stop dangerous change.”Another government initiative to cut emissions was announced yesterday with plans to electrify thousands of miles of railway track. The Midland Main Line and the Great Western Main Line, which run diesel trains, are likely to be converted to electricity over the next decade. At present only 40 per cent of the 20,000-mile network is electrified.

Lord Adonis, the Transport Secretary, pledged the move as part of his department’s strategy for reducing CO2 emissions from transport by 14 per cent by 2020. He also announced a tough emissions standard for cars that will qualify, from 2011, for grants of up to £5,000. Only electric and plug-in hybrid cars that emit 75g per km of CO2 or less will be eligible.

There are a few small electric models that will qualify but no hybrids. The best-performing hybrid, the 2009 Toyota Prius version, emits 89g/km.