In a blog post, CEO Juliet Davenport said it does “much more to support growth in renewables and clean technologies than others”.

The average cost of a Good Energy tariff is around £1,422 a year, compared with the price cap average of £1,254.

The firm lobbies for greater take up of renewables in the UK and says it is the first supplier to offer 100 per cent green energy to consumers.

Regulator Ofgem said the company could continue to charge its 250,000 customers a premium as it could locate the source of all its energy supplies.

Suppliers who claim to offer ‘100 per cent green’ energy tend to buy the majority of their electricity on wholesale markets, then buy certificates called “REGOs”, which guarantee the equal amount of electricity created from fossil fuels is matched by renewable generation.

Davenport said these companies “are taking shortcuts to offer low-cost ‘green’ tariffs which mislead customers into thinking they are choosing to support the growth of renewables, when really they are just paying for fossil fuel power and some cheap certificates.”

Good Energy uses power purchase agreements, which involve buying electricity directly from wind farm and solar generators.

“If we are going to tackle climate breakdown, individuals must be empowered to choose to be part of the solution,” Davenport said.

Ofgem had initially given Good Energy a temporary exemption in January 2019 when the cap was introduced. This lasted until the end of March, but was extended until September, then finally made permanent.

It said the decision was made because it recognised customers on Good Energy’s standard variable tariff (SVT) had chosen to be on it, unlike customers who have been on SVTs for several years without necessarily knowing.

Officials added that the support for renewables provided by the extra cash is “materially greater” than “regulatory mechanisms”.

Last month, government statistics showed that over 50 per cent of the UK’s electricity was generated from low-carbon sources in 2018.

In a blog post, CEO Juliet Davenport said it does “much more to support growth in renewables and clean technologies than others”.

The average cost of a Good Energy tariff is around £1,422 a year, compared with the price cap average of £1,254.

The firm lobbies for greater take up of renewables in the UK and says it is the first supplier to offer 100 per cent green energy to consumers.

Regulator Ofgem said the company could continue to charge its 250,000 customers a premium as it could locate the source of all its energy supplies.

Suppliers who claim to offer ‘100 per cent green’ energy tend to buy the majority of their electricity on wholesale markets, then buy certificates called “REGOs”, which guarantee the equal amount of electricity created from fossil fuels is matched by renewable generation.

Davenport said these companies “are taking shortcuts to offer low-cost ‘green’ tariffs which mislead customers into thinking they are choosing to support the growth of renewables, when really they are just paying for fossil fuel power and some cheap certificates.”

Good Energy uses power purchase agreements, which involve buying electricity directly from wind farm and solar generators.

“If we are going to tackle climate breakdown, individuals must be empowered to choose to be part of the solution,” Davenport said.

Ofgem had initially given Good Energy a temporary exemption in January 2019 when the cap was introduced. This lasted until the end of March, but was extended until September, then finally made permanent.

It said the decision was made because it recognised customers on Good Energy’s standard variable tariff (SVT) had chosen to be on it, unlike customers who have been on SVTs for several years without necessarily knowing.

Officials added that the support for renewables provided by the extra cash is “materially greater” than “regulatory mechanisms”.

Last month, government statistics showed that over 50 per cent of the UK’s electricity was generated from low-carbon sources in 2018.