What is 'green' energy?
'Green' energy is power from renewable sources, as opposed to energy generated through the use of fossil fuels.
Renewable forms of energy include wind, solar and wave power, as well as tidal, biomass and hydroelectric power.
Because all electricity, no matter how it is generated, is supplied through the National Grid, there is no way to ensure that the green energy you pay for actually comes to your home - but what you will know is that you're helping to add more energy from renewable sources into the overall 'mix' of fuel in use throughout the country.
Some suppliers of green energy are also working to create more environmentally-friendly gas and dual fuel tariffs, as well as offering greener electricity.
Is it possible to buy energy from a specialist green supplier?
Yes. There are a number of energy companies in the UK who specialise in green and renewable energy. Among them are providers such as Ovo, Ecotricity and Good Energy, whose tariffs are included in MoneySuperMarket's energy comparison channel.
Dedicated green energy suppliers, and mainstream suppliers who offer green energy tariffs, source a greater proportion of their power from renewable sources - but not always 100%.
You can check how much renewable energy any power supplier is using to produce electricity by looking at its 'fuel mix' information. Energy providers are required by Ofgem to publish these figures annually, to show how much of the power they sell has come from coal, gas, nuclear sources, renewable sources and other sources. You should be able to find them on companies' websites.
Is green power likely to be more expensive?
Possibly - though with public interest in green energy on the rise, tariffs from specialist providers are often competitively priced in order to attract new customers.
If you're interested in switching to a green energy supplier, it's well worth comparing what they have to offer with the cheapest deals you can find from mainstream providers.
How can I compare green energy deals?
It's easy to compare green energy deals, and to look at them alongside tariffs from the UK's 'big six' energy suppliers - British Gas, E.ON, SSE, npower, EDF and Scottish Power.
MoneySuperMarket's energy comparison channel includes tariffs from a wide variety of suppliers, including those who specialise in renewable power, to help you make the decision that's best for you.
*51% consumers, MoneySuperMarket data, May 2015