Eon is now supplying all its residential customers in the UK with 100% renewable electricity as standard and at no extra cost.
The change means more than 3.3 million homes now have an electricity supply matched by renewable sources including wind, biomass and solar, the company said.
Eon said it is directly supplying a large proportion of the renewable electricity from its own generation fleet, as well as through agreements with independent wind generators around the country to directly purchase the power produced.
The remaining electricity used by customers is matched with 100% renewable electricity sourced externally through such things as renewable electricity guarantee certificates.
These certificates guarantee that an equivalent amount of renewable electricity was generated to the amount supplied.
Eon UK chief executive Michael Lewis said: “Climate change is the defining issue of our era, and one that energy customers are increasingly concerned about.
“We believe large-scale action can make significant change possible and we’re committed to playing a leading role and setting an example for others to follow, that’s why we’re providing all of our residential customers with 100% renewable electricity as standard – a change at a scale never seen before in Britain.
“Our announcement is an important first step in a journey towards a more sustainable and personalised energy system, but the future of energy doesn’t stop here.
“The opportunities include helping all of our customers to better manage their energy through smart, personalised and sustainable technologies.”