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Which? reveals new Eco Providers for energy

Find out how your gas and electricity supplier shapes up, plus how to use greener electricity without switching energy company
Choosing a green paint swatch

Good Energy, GEUK and Ecotricity are Which?'s first Eco Providers for energy, our analysis of how energy companies provide renewable electricity and gas reveals.

Some 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. While others do the minimum required to label their tariffs 'green'. But the language around 'green energy' can be difficult to translate, making it hard to know what you're paying for if you're looking for the greenest tariffs.

We asked over 40 energy companies to tell us specifics about the green electricity and gas they sell to homes, and looked at their websites to see how easy it is for customers to understand what they're buying.

Each company was given a rating out of 20. There was a gap of 18 points between the highest and lowest scores. Keep reading to find out how your provider fared.

Find out more about the differences between green energy suppliers.

Energy providers compared for sustainability

Wind turbines on a hilltop

With sharply-rising prices, you might find you're paying more to heat and power your home this winter. So it's more important than ever to know what you're getting for your money. Especially if your energy company's green credentials are important to you - as they were for half of 965 Which? members in our survey in July 2021.

The scores in our provider analysis were based on information provided by each company and publicly available on their websites.

We looked at the following measures:

  • 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 were awarded to those that generate renewable electricity or buy it directly from generators, more for a greater percentage;
  • Matching customers' use with renewable power: points were 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 were deducted for generating electricity from fossil fuels, buying from fossil-fuel generators or having carbon intense generation in their fuel mix;
  • Green gas: points were added for selling green gas, more for a higher percentage;
  • Transparency and website clarity: points were awarded for websites that are clear about how renewable electricity is sourced, and for sharing data with Which?*

The table below shows how each company fared. Suppliers are included whether or not they made green claims to give you the full picture. Scroll right if you can't see the full table.

CompanyOverall scoreSale of renewable electricity (max 2)Generating and buying renewable power directly (max 8)Matching customers' use with renewable power (max 5)Carbon intense power (max -2)Green gas (max 2)Transparency and website clarity (max 3)
Good Energy19275023
British Gas Evolve12260013
Scottish Power11.5072.5-103
British Gas11160013

**Octopus Energy supplies their power.***Owned by Ovo.

Notes on the table above

Data provided by companies in August and September 2021, as much of it is not publicly availably. Suppliers shared their latest fuel mix (either 2019-20 or 2020-21). We also looked at their websites.

*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 electricity claims.

Where companies didn't respond or supply the information we requested, they earned zero points and are not featured in the table. 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 several which provided information). They are: Avro Energy, Enstroga, Goto Energy, Green, Igloo Energy, Moneyplus Energy, People's Energy, PFP Energy, Pure Planet, Symbio Energy and Utility Point. Read the latest updates about this autumn's failing energy suppliers.

Our assessment doesn't cover everything companies do to reduce their environmental impact. We plan to return to this in future and factor
in broader sustainability credentials.

Green energy company credentials

Green colour chart

Our Eco Providers are long-standing sustainable frontrunners.

  • 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. In November 2021 it announced plans to sell of its solar and wind farms but will buy enough renewable electricity for all customers directly from other generators. Find out more about Good Energy.
  • GEUK doesn't generate renewable electricity itself but said that it buys enough directly from its network of commercial and independent renewable generators in the UK to match its customers' use. It's the only energy firm to sell 100% green gas.
  • 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 and British Gas Evolve generate renewable electricity and buy some direct from generators. Around two-thirds of their electricity is matched with renewable power generated outside the UK. Read more about British Gas.
  • Scottish Power 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 only backed by green energy certificates. Find out more about Scottish Power.

Fast-growing brands Bulb and Octopus Energy (including its partner brands) also scored well - both buy some renewable power directly from generators. Octopus also generates some itself. Find out more about Bulb and Octopus Energy.

Not all companies take the same approach, which makes comparison difficult. Some companies question whether focusing on fuel mix is the best route to net zero. For example, Utilita .told Which? that it places an emphasis on helping households to use less energy. It's worth reading up on what providers are doing in this space before you switch, if it's something that is important to you.

We've added the data we collected to our energy company reviewsto make it easier for you to find out about your energy company's renewable electricity and green gas (where they shared it with us).

Renewable energy certificates confusion

Solar panels

To be able to call a tariff 'green' or 'renewable', a supplier matches the electricity you use with energy generated from a renewable source.

They do this with renewable energy certificates or REGOs (Renewable Energy Guarantees of Origin). These are a bit like birth certificates issued for every megawatt hour of renewable power generated.

But they're not attached to the power so companies can buy and sell them separately - and often cheaply.

Some companies buy REGOs in isolation, while others also generate renewable electricity themselves, invest in building more renewable infrastructure or buy renewable power directly from generators.

When we asked 965 Which? membersin July 2021 about their expectations of companies selling green tariffs:

  • 72% expected they buy renewable electricity from other companies or generators
  • 67% expected they generate their own renewable electricity.

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 65% of members told us that the most important thing about green tariffs is transparency about where a company's renewable energy comes. Currently, it can be tricky to tell what you're buying.

It's so murky that the government department BEIS has called for evidence to 'explore the extent of u201cgreenwashingu201d in the energy sector'. The Competition and Markets Authority (CMA) has published new guidelines on making environmental claims too.

How to use greener energy without switching supplier

Hydroelectric dam

No matter which supplier you're with, or which tariff you choose, we all pay around £220 per year through your bills towards new renewable generators.

Electricity from all fuel sources - coal and gas as well as renewables - is mixed together in the grid so suppliers can't determine the precise electricity you get to your home.

The same is true of green gas; it's similarly mixed into the national gas supply. Find out more about green gas.

So while you can buy 100% renewable electricity or green gas, you're not literally using it in your home. You're paying for a proportion of the overall mix.

There are plenty of ways to make your energy use greener. If you can, consider the following:

  • Cut down the amount of electricity you use at home. The greenest energy is that you don't use at all. Follow our tips for using less electricity.
  • Use electricity for charging or running appliances when it's less carbon-intense (this is usually during the night). Spreading your usage into times when there's less demand for electricity means it's less likely that back-up power is needed by the grid - which is often fossil fuel generated.
  • Make sure that you're using as little heating as possible to stay warm. Find out how to make your home more energy efficient.
  • Install solar panels on your home to ensure that at least some of the electricity you're using is truly renewable. Find out if your home is suitable for solar panels.
  • Consider a heat pump when your gas boiler needs replacing. They're pricey to install but use naturally-occurring heat to warm your home. Find out more about air source heat pumps.