Government hopes to encourage households to get more of their energy from renewable sources were branded a “greenwash” last week, as they contained no concrete plans to cut the cost of alternative fuel.

Gordon Brown pledged £100 billion to generate 15% of Britain’s energy from renewable sources by 2020. Part of the strategy is to encourage people to move to greener tariffs or produce their own power.

However, green energy tariffs, where some or all the electricity produced is from a renewable source, can cost as much as 56% more than the cheapest deals, according to comparison firm The Energy Shop.

Meanwhile, those opting to produce electricity through wind or solar microgenerators may not see a saving for more than 30 years because of the costs involved, according to Solar Home Energy, which provides solar panels.

The government offers grants to help with the costs, but these are limited and there are no plans to improve matters until 2010.

Alex Lambie of Greenhelpline.com said: “It is a recurring theme of this government to make grand and encouraging proposals about tackling climate change without being transparent about what’s being offered.”

British Gas’s Future energy tariff, which promises that 100% of your energy will come from renewable sources, costs £414 a year for electricity. However, British Gas’s cheapest deal is Click Energy 5 which costs £316 a year. Good Energy, a green energy provider, charges around £502 a year.

There is also a lack of clarity over how much energy has to be produced from renewable sources to be classified as a green tariff. Green Energy’s Pale Green tariff, for example, which costs about £458 a year, only sources 20% of its energy from renewables while Ecotricity’s New Energy tariff only gets 10%.

With some, none of your energy will be from renewable sources. Scottish Power’s Green Energy Offer Tariff donates £10.50 a year to green projects instead.

Even where the energy is from alternative sources, there is no guarantee that your tariff will boost the amount of renewable energy your firm produces overall. Under current government guidelines, energy suppliers have to source at least 7.9% of their energy from renewable sources anyway, rising to 15.4% by 2015.

If you sign on to a green tariff, your supplier may therefore simply divert green energy from another customer instead.

Ofgem, the energy regulator, hopes to publish official guidelines in July which will standardise the criteria for green energy deals. A spokesman said the guidelines will “make it clearer to customers which tariffs offer real environmental benefits”.

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