Supplier E.On is to provide all of its residential UK customers with an electricity supply that is wholly matched by renewable sources including wind, biomass and solar.
It's one of the biggest green energy switches to date, and comes at no extra cost to customers.
A recent survey found 77% of households said they were concerned with climate change, and 79% said they could improve their own sustainable behaviour.
"For every kW hour of electricity we sell to our residential customers, we will ensure that 1kW hour of renewable electricity is produced onto the system. And that comes either from the own assets that we've built or with partnerships with developers we have, or by buying them on the market," Michael Lewis, the UK chief executive of E-On explains to BBC Radio 4's Today programme.
"It means we've got a one-to-one match to drive renewable electricity in the market and it gives our customers what we believe they want."