Energy regulator Ofgem is today releasing guidelines for householders to help them decide which electricity and gas suppliers are the most environmentally friendly.
Ofgem hopes that the new system which rates suppliers' tariffs on a scale from A to F much like the system used for rating the energy efficiency of domestic appliances will "cut through green customer confusion".
Ratings will be based on the "carbon intensity" of the energy production methods underlying a tariff, including the proportion of electricity generated from renewable sources.
"Currently, customers find it difficult to compare the environmental benefits of the various energy deals on offer," said Ofgem chief executive Alistair Buchanan.
The proposals have not been universally welcomed by consumer groups, however.
Both the National Consumer Council (NCC) and energywatch have acknowledged the need to clear up confusion about the environmental standards of different energy suppliers, but both organisations have warned that the scheme may not go far enough.
In particular, concern about the still-unclear definition of "low carbon" remains.
Click here to run an energy price comparison, and see if you could be paying less for your gas and electricity.