Which? reveals first Eco Providers as it rates energy firms on sustainability

Good Energy, GEUK and Ecotricity have beaten the biggest energy firms to be named the best providers on sustainability, Which? research reveals, with all three crowned Which?’s first Eco Providers for energy.

British Gas, Scottish Power, Bulb and Octopus were the best of the ‘big’ providers on sustainability in Which?’s analysis of more than 40 energy firms, but failed to meet the standards set by the three smaller suppliers named as Eco Providers.

Climate-conscious energy customers are increasingly seeking out renewable tariffs and a new Which? survey of more than 900 members found that 50 per cent consider the sustainability of energy suppliers to be important.

Seven in 10 (72%) of those surveyed said they expect that companies selling green tariffs will buy renewable electricity from other companies or generators, while a similar number (67%) expected that the company generates its own renewable electricity.

More than a dozen energy suppliers have ceased trading in recent months amid soaring wholesale gas prices, resulting in consumers paying more to heat and power their homes. This has reinforced the importance of firms providing clear information for customers about what they are getting for their money, especially if their supplier’s green credentials are vital to them.

To find out how energy companies match up on sustainability, Which? asked over 40 energy companies about the renewable electricity and green gas they sell to homes, and looked at their websites to see how easy it is for customers to understand what they are buying. Each company was given a rating out of 20 and there was a gap of 18 points between the highest and lowest scores – among those firms which responded.

Good Energy (overall score of 19 points), GEUK (16) and Ecotricity (14) topped Which?’s rankings to become Eco Providers for energy, with their approach to renewable gas and electricity largely matching what most environment-conscious customers would expect. All three are long-standing sustainability frontrunners in the energy market.

Good Energy buys the majority of its renewable electricity directly from generators, including more than a thousand small-scale producers. It also generates some renewable electricity using solar and wind, and sells green gas.

While GEUK does not generate renewable electricity itself, the supplier said that it buys enough directly from its network of commercial and independent renewable generators in the UK to match its customers’ use. It is the only energy firm to sell 100% green gas.

Meanwhile, Ecotricity generates some renewable power, buys some of it directly from generators and matches the remainder with green energy certificates. It puts customers’ money towards building new renewable generation.

Other bigger, established providers rank well too. British Gas (overall score of 11) and British Gas Evolve (12) generate renewable electricity and buy some directly from generators. Around two-thirds of their electricity is matched with renewable power generated outside the UK.

Scottish Power (11.5) says it’s ‘one of the biggest developers and generators of renewable electricity in the UK and Ireland’. None of the electricity it sells is backed by green energy certificates only.

Fast-growing brands Bulb and Octopus Energy (11) scored well, with both buying some renewable power directly from generators. Octopus also generates some renewable energy itself.

In contrast, Northumbria Energy, Utilita and Utility Warehouse only picked up a handful of points between them. None generate or buy any renewable power directly from generators, or buy enough certificates to label all of their power 100% renewable. Some companies question whether focusing on fuel mix is the best route to net zero. Utilita, for example, told Which? it was set up to help households to use less energy.

To be able to call a tariff ‘green’ or ‘renewable’, a supplier matches the electricity consumers use with energy generated from a renewable source. They do this with renewable energy certificates or REGOs (Renewable Energy Guarantees of Origin). But they are not attached to the power so companies can buy and sell them separately – and often cheaply.

The Committee on Climate Change said that unbundling REGOs from power “could mean that the supplier of the green tariff is not actually purchasing renewable electricity, but it’s simply purchasing the certificate”.

Not all companies can generate renewable electricity. The upfront costs are high and revenue streams uncertain. But two thirds (65%) of Which? members said that the most important thing about green tariffs is transparency about where a company’s renewable electricity comes from.

The consumer champion believes the rules about marketing green tariffs and supplier credentials need to be clearer and go beyond the basics so customers can be confident in what they are buying.

Harry Rose, Which? Magazine Editor, said:

“We know consumers are growing ever-more environmentally conscious, and our research shows that some energy firms go to great lengths to invest in the technology we need to clean up the grid, generate renewable electricity, or buy it from renewable generators.

“However, some other energy suppliers do the minimum required to label their tariffs ‘green’ and it can be hard for consumers to understand what they are buying.

“Which? believes there needs to be greater clarity on how renewable electricity is defined and marketed. People can only make informed decisions about where to buy their energy from if firms are more upfront and transparent about their green credentials.”

Notes to editors:


The results are based on an online survey of 965 members of the Which? Connect panel conducted in July 2021. When Which? surveyed its members, 50% said an energy provider’s sustainable credentials are important to them. Some 72% of those Which? surveyed said they expect that companies selling green tariffs will buy renewable electricity from other companies or generators. A similar number (67%) expected that the company generates its own renewable electricity.

Energy providers compared for sustainability:

Scores were based on information provided by each company to Which? and publicly available on their websites, which looked at the following:

  • Sale of renewable electricity: companies gained points for selling 100% renewable electricity or more than average, shown by their latest fuel mix disclosure.
  • Generating and buying renewable power: points awarded to those that generate renewable electricity or buy it directly from generators, more if it’s a greater percentage.
  • Matching customers’ use with renewable power: points given for firms that generate or buy enough renewable power directly to match their customers’ use, and match it with certificates. Points were lost where matched electricity was not generated in the UK.
  • Carbon intense power: points deducted for generating electricity from fossil fuels, buying from fossil-fuel generators or having carbon intense generation in their fuel mix.
  • Green gas: points for selling green gas, more for a higher percentage.
  • Transparency and website clarity: points awarded for websites that are clear about how renewable electricity is sourced, and for sharing data with Which?.*

*One point was given for responding to our questions. Companies got another two points if their websites made clear whether they generate, buy direct, buy REGOs in isolation or do a combination. Companies got one point if their information was less complete. Companies didn’t get those points if they didn’t provide information on their website to explain their 100% renewable electricity claims or didn’t make renewable claims. Where companies didn’t supply the information we requested, they earned zero points and are not featured in the table.


Data provided to Which? by companies in August and September 2021. Suppliers shared their latest fuel mix (either 2019-20 or 2020-21). We also looked at their websites. Companies that did not supply the information required scored zero points. They were: Ampower, E, EDF Energy, Entice Energy, Nabuh Energy, Neo Energy, Zebra Power.

Several providers have gone bust since we conducted this assessment (including some which provided information). They are: Avro Energy, Enstroga, Green, Goto Energy, Igloo Energy, Moneyplus Energy, People’s Energy, PFP Energy, Pure Planet, Symbio Energy and Utility Point.

About Which?

Which? is the UK’s consumer champion, here to make life simpler, fairer and safer for everyone. Our research gets to the heart of consumer issues, our advice is impartial, and our rigorous product tests lead to expert recommendations. We’re the independent consumer voice that influences politicians and lawmakers, investigates, holds businesses to account and makes change happen. As an organisation we’re not for profit and all for making consumers more powerful.

The information in this press release is for editorial use by journalists and media outlets only. Any business seeking to reproduce information in this release should contact the Which? Endorsement Scheme team at endorsementscheme@which.co.uk.

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