The green energy switchover: Five things you need to know

Is this just about being environmentally friendly? It's also about saving money on your gas and electricity bills. A campaign group called the Clean Energy Switch plans to cut the cost of renewable energy and make it affordable for families.

How is renewable energy different? It's not fossil-fuel based so it doesn't use up scarce resources. Energy is generated from wind, sun and water through such technology as wind farms, solar panels or hydro-electric dams.

Sounds good. Why don't more people use it? It's more expensive to generate power this way than with traditional fossil fuels, so cash-strapped people think they can't afford to turn to green energy. The new mass switch, launched on Tuesday, hopes to change that by using collective bargaining to secure a more affordable deal. The greater the number of people who sign up, the more likely it is that a green energy provider will be able to offer a keener price – at least that's the hope.

Are there many people interested? There certainly are. At least 42,000 households signed up in the first 48 hours of the campaign, and the organisations behind it – 38 Degrees and the Big Deal – believe it could become the biggest collective customer switch from fossil fuels to renewable energy seen in the UK.

There's also cross-party political support for the campaign. "By harnessing the power of consumers, we can make it easy for people to help combat climate change, save money and support the renewables industry," said Angus MacNeil, chairman of the Energy and Climate Change Select Committee and the SNP MP for Na H-Eileanan An Iar.

How do I take part? You can sign-up for free at thebigdeal.com or 38degrees.org.uk by entering just an email address and postcode.

Signing up does not commit you to anything. If you don't like the rate negotiated, you don't have to take the deal.