"In the UK about two thirds of our electricity is generated by burning coal and gas in power stations. This releases millions of tonnes of carbon dioxide, the main gas responsible for climate change, every year. The other third of electricity mainly comes from nuclear power, which has other worryingly severe environmental impacts. Green electricity’' means electricity produced from sources which do not cause these impacts upon the environment. Of course, every type of electricity generation will have some impact, but some sources are much greener than others." (Quoted from article)