Good Energy is an electricity supplier that supplies 100% renewable energy. They don't use fossil fuels or nuclear power. On their website they say it costs an average family a few pounds more each month, but my direct debit went down when i moved to them.
Here is their website. You can sign up on-line.
This is a list that shows how the different suppliers compare.
I know i sound like their marketing department but I'm just a mum with small kids worried about GW!!!