As the effects of climate change become clearer, the desire to be more conscious of our energy usage increases. That’s why more people than ever are choosing to switch to greener energy companies, so they can power their homes with electricity not generated from damaging fossil fuels.
Knowing which green energy company to go with isn’t the easiest task, though, especially as more and more energy suppliers are parading their green credentials without actually explaining why they’re so green.
Thankfully, we’ve done the legwork for you, researching the top green energy suppliers in the UK and creating a handy shortlist of the very greenest energy companies you can choose.
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Key Points:
Octopus Energy was our overall pick for the greenest energy supplier in the UK.
42.3% of the UK’s energy comes from renewable sources.
Many green energy suppliers will actually pay (via the Smart Export Guarantee) you for any excess electricity you generate from renewable sources.
Not all suppliers claiming to be green offer 100% renewable tariffs, so keep an eye out for this.
However, green tariffs are still better for the environment than non-green tariffs, as they tend to be a mix of clean power and power generated by fossil fuels.
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How We Picked the Greenest Energy Suppliers in the UK
First and foremost, how an energy supplier generates its electricity is the number one ranking factor in this list. The more electricity generated by renewable sources, the better an energy supplier will do.
Secondly, we’ve considered the emissions of each energy supplier. They might use electricity generated from renewable sources, but if their emissions are offsetting the benefits of green power, that’ll work against them.
Other important factors in how we picked the greenest energy suppliers include:
Their Smart Export Guarantee (SEG) rates. Energy suppliers of a certain size (150,000 customers or more) are obligated by the UK government to pay green energy generators (that’s you!) a rate per kilowatt hour (kWh) of clean electricity exported back to the grid. The more they pay, the better they’ll do.
Time of use (TOU) products offered. Companies offering good TOU products that reward customers for using electricity outside of peak demand.
Help installing low-carbon technologies. Any suppliers that help customers install low-carbon technologies such as solar panels and heat pumps get a boost from us in where we rank them.
Whether they offer green gas. Green gas is a renewable and low-carbon alternative to traditional natural gas produced from organic matter breaking down.
Their customer reviews. It’s all well and good being green, but a supplier should also provide a customer service that makes them a joy to use.
The Top Five Greenest Energy Companies in the UK
Here’s our pick for the top five energy companies you should consider if green energy and sustainability are a priority:
1. Octopus Energy
As one of Europe’s biggest investors in renewable energy sources, Octopus Energy is a supplier unafraid to walk the walk as it talks the talk. It currently manages over 700 green energy producers in the UK, powering more than 1.2 million homes across the country with green electricity.
All (yes, all, not some) of its electricity comes from solar, onshore and offshore wind. Octopus Energy has even started buying its own energy generators and currently has a number of wind farms in operation.
As a result, it’s created a quirky offering called the Octopus Fan Club, which rewards members with up to 50% off their energy costs when the wind picks up. The only caveat is you need to actually live near the wind farms, but if you already do, there’s little reason not to join the Octopus Fan Club.
In terms of green tariffs, the Super Green tariff offered by Octopus Energy is completely carbon neutral, which is unlike a lot of other “green” tariffs that combine electricity from renewable and non-renewable sources. Octopus Energy also says it fully offsets any carbon emissions from gas with the Super Green tariff.
You can get solar panels and heat pumps installed with Octopus Energy too, and with the former, any excess electricity you generate can be sold back to the grid. Octopus Energy offers some of the best Smart Export Guarantee (SEG) rates around – if you go for the Octopus Flux tariff, you’ll get 26p per kilowatt hour (kWh), though rates depend on what time of day you export.
Not bad, right? And Octopus Energy does all this while maintaining a hugely impressive 4.8 stars out of 5 on TrustPilot, from 584,653 reviews at the time of writing (April 2025). The future looks bright for the supplier too, with plans to be fully net zero by 2040.
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2. Ecotricity
Ecotricity’s whole schtick is using its profits to build more renewable generation, which it calls “bills to mills” (as a lover of puns and wordplay, this is glorious). This, in turn, allows it to continue expanding and providing UK customers with what it claims is 100% green energy.
The supplier uses a mix of solar, wind, and hydro power, and currently has 24 wind parks located all across the UK. These wind parks (and several solar farms) make up around 15% of the energy Ecotricity supplies, with the remaining 85% all coming from other green generators it purchases from.
Ecotricity aimed to be carbon neutral by 2025, and though no update has come out yet as to whether it’s fully achieved this, the supplier is definitely on the right track.
It takes a holistic approach to its environmental impact, aiming to ‘greenify’ every aspect of its operations.
This includes making sure its electricity sources are green, which is the obvious part, but Ecotricity also takes great care when selecting sites for its solar farms and wind parks. The idea is that you can’t just plonk solar panels and wind turbines without considering the environments they’re being placed in, and we’re big fans of this approach.
You can also use its own carbon footprint calculator to see what your emissions are and how you can take little steps to reduce them.
Ecotricity’s green credentials are impressive, but you do pay a higher price to go with its 100% green tariffs. We found that their tariffs on average cost more than other green suppliers in the UK, though we will say that they don’t pretend to be cheaper. See, Ecotricity doesn't have any shareholders, so all of the money they make is reinvested in renewable energy generation.
So if you don’t mind paying a little bit more for your energy, and want the peace of mind knowing your money is going to an environmentally friendly cause, Ecotricity is a great choice.
If you have solar panels and want to sell excess electricity, you currently can’t do that via Ecotricity. The supplier has announced that it’s planning to launch its smart export tariff soon, so stay tuned!
Overall reviews for Ecotricity are positive, and the supplier boasts an average of 4.2 stars out of 5 on TrustPilot. The most negative aspects focused on the cost, though customers seemed to really love the lack of shareholders, customer service, and how easy it was to switch from old providers.
3. Good Energy
Good Energy is one of the good guys in the industry, with its commitment to paying smaller renewable energy generators a fair price for the electricity they provide. In fact, roughly 40% of the energy suppliers Good Energy buys from don’t get government subsidies.
Why is this important? It means Good Energy is supporting generators that might not otherwise exist without government support. Practices like this encourage the growth of smaller renewable energy generators, increasing the UK’s capacity for green electricity overall. Nice one, Good Energy.
Also, 10% of the gas Good Energy provides is green. Green gas is a low-carbon, renewable alternative to traditional gas and is much harder to generate than renewable energy, coming from biomethane, which is a byproduct of breaking down organic waste.
Good Energy’s tariffs are all Uswitch Gold accredited too, so you can guarantee that any tariff you opt for will use 100% renewable energy.
Additionally, when it comes to carbon offsetting, Good Energy is heavily involved in installing biogas digesters in parts of India and China. These biogas digesters break down organic waste into heating, cooking, or electricity generation, and the remaining waste makes excellent fertiliser.
Good Energy looks more than good when it comes to customer reviews – rather, it’s looking pretty excellent with 4.8 stars out of 5 on TrustPilot. The speed at which Good Energy dealt with issues was one of the most frequent positives we noticed, as was how friendly the customer service was in general.
3. 100Green
100Green is the only company on this list that provides customers with 100% renewable electricity and 100% green gas, which explains the name! It generates its electricity from solar power, wind power, and hydro power, and its greenhouse gas comes from breaking down waste from farms, food, and landfills.
As for available tariffs, there’s some great flexibility and options if you’d like to contribute more to sustainable initiatives.
For example, you can choose the premium fixed-rate tariff that includes local wildlife protection, where energy is generated. There are convenient time-of-use tariffs available too, which give you lower-rate electricity between midnight and 7 am – ideal for charging your electric vehicle or running your washing machine.
All this green goodness does mean you’re likely to pay more for tariffs, and like Ecotricity and Good Energy, 100Green is exempt from Ofgem’s price cap.
But if you really want a supplier truly dedicated to making the UK (and the World) a greener, better place to live, there are few companies better than 100Green.
Customers tend to agree that 100Green is worth spending a little extra on, with an average score of 4.1 out of 5 on TrustPilot. Most people loved how eco-friendly the supplier is, but also, how the company has real people responding to queries – a big plus in the age of AI chats and automated responses.
4. OVO Energy
OVO Energy launched in 2009 and now supplies electricity to around 4.5 million UK homes. This is through a mix of renewables, nuclear, other (unspecified), but also coal.
You’re right in wondering why we’ve included a supplier still using fossil fuels (especially one as dirty as coal) in our list of greenest energy suppliers. However, OVO Energy earns its place here through its commitment to net zero and rapid reductions in carbon emissions.
It plans to reach net zero by 2035 – a full five years ahead of frontrunner supplier Octopus Energy. OVO Energy also offers the widest range of sustainable installations, including solar panels, battery storage, insulation, heat pumps, and EV chargers.
And speaking of emissions, the energy supplier has shrunk them by more than 5 million tonnes from 2018 to 2023. That’s the equivalent annual emissions of nearly 400,000 people in the UK.
There are also several tariffs available from OVO Energy that reward customers for using electricity when there’s lots of renewable energy available. Power Move, for example, is a tariff offering chances to win prizes simply for using electricity at greener times of the day.
Unfortunately, OVO Energy falls short when it comes to customer service, according to Which?. The website ranked the supplier near the bottom of its customer survey, with poor communication and overall value for money among the aspects customers disliked the most.
How To Choose a Green Energy Supplier
Choosing a green energy supplier can be confusing, considering the sheer volume of suppliers all vying for your attention. There are a few things to keep an eye out for, though, that should make it a little easier:
Tariffs
Don’t be convinced by a tariff just because it has the word green in it. In fact, green tariffs can still use non-renewable energy sources, and just because a company sounds eco-friendly, it doesn’t mean it is. Instead, focus on looking for tariffs using terms such as renewable energy, renewable gas, and carbon offset.
Customer Service
You don’t want to switch to a green energy supplier and find that any issues you might have are dealt with poorly, if at all. Use websites such as TrustPilot to get an idea of other people’s experiences, as well as how (or if) the company replies to both positive and negative reviews.
Transparency
Transparency is, in our opinion, a hugely important part of choosing a green energy supplier. After all, greenwashing has been rife in the industry, and if you’re going to switch to a new supplier, who might not be cheaper than your current one, you want a guarantee that they’re actually green.
Look out for how transparent suppliers are about their energy sources and whether they have any links to fossil fuels. Big oil companies such as Shell have been accused of greenwashing by offering limited renewable energy options while still continuing to pump out oil and making record profits.
A great example of transparency for us was with supplier Ecotricity fully owning up to a coolant leak from its wind turbines in 2023. This resulted in around 59 tonnes of greenhouse gases (GHGs) entering the atmosphere, which it said amounted to around a third of the company’s total annual emissions. A lot of companies, we’re sure, would bury this in obscure statistics, but Ecotricity held its hands up and was wholly honest about it.
Are There Any Government Incentives for Switching to Green Energy?
There are several initiatives available to encourage switching to green energy suppliers. The two main incentives to consider are:
The Energy Company Obligation (ECO) scheme. This initiative requires certain energy suppliers to provide funding for home improvements for eligible homes. The improvements include insulation, heating upgrades, and renewable energy installations.
The Smart Export Guarantee. If you have your own renewable energy source, such as solar panels, you can sell any excess electricity you don’t use back to the grid via the SEG. Certain suppliers will pay you per kWh, and although it’ll only ever amount to a few pence per kWh, it’s still free money. And, you’ll shrink the time it takes to pay back the investment in whatever renewable energy generator you purchased.
Further reading:
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