Top 5 UK green energy suppliers 2025

Written by Lori Campbell on 5th Jun 2025

Why switching to green energy matters in 2025

Switching to a green energy supplier is one of the most impactful steps individuals can take to combat climate change. Around 75 per cent of global greenhouse gas emissions come from burning fossil fuels for electricity and heating – making the energy sector both the largest contributor to the climate crisis and a powerful part of the solution.

To meet global climate goals, emissions must be halved by 2030 and reach net-zero by 2050. That starts with replacing fossil fuels with renewable electricity from wind, solar, hydro, and biogas – clean energy sources that are naturally replenished and emit little to no carbon.

Here are our top five green energy suppliers in the UK:

Ecotricity

Ecotricity is one of the UK’s leading green electricity suppliers, offering 100 per cent renewable energy from wind, solar, and hydro sources. It also stands out as a certified vegan energy provider, meaning its gas and biomass sources are completely animal-free.

Its gas offering includes a combination of carbon-offset natural gas and a growing proportion of biomethane produced from grass cuttings via its pioneering “green gasmills.”

With no shareholders, Ecotricity reinvests all profits into developing new forms of renewable energy. It maintains a strict no-greenwashing policy and was named a Which? Eco Provider for the fourth year running in 2024.

Ecotricity was the first energy company to call for a halt on deep sea mining. Its website has a Carbon Footprint Calculator to help customers reduce their environmental impact and recently launched a smart grid scheme to boost grid-wide renewable usage and cut customer costs.

While not the cheapest provider, Ecotricity prioritises sustainability over price. It says: “We set our prices at a level that allows us to do our job of building new sources of green energy – as we seek to end the use of fossil fuels in the energy sector.”


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100 Green

100Green is the only green energy supplier in the UK offering 100 per cent fossil-free electricity and gas on all tariffs – hence the name. The electricity comes from certified solar, wind, and hydro sources. Its green gas is produced via anaerobic digestion of farm, food, and landfill waste and is traceable to its source.

Ethical Consumer ranks 100Green a ‘Best Buy’, and it holds an ‘Eco Provider’ badge from Which? It also has a solid 4-star rating on Trustpilot.

100Green is ideal for those who want a truly fossil-free energy supplier – though it does come at a premium compared to more mainstream providers.

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Good Energy

Good Energy is frequently ranked among the best renewable electricity companies in the UK, thanks to its direct support of more than 2,000 independent UK generators. Unlike providers who rely heavily on green certificates, Good Energy matches customers’ usage with genuine renewable power and pays a fair rate to generators, helping to grow the sector.

It has a ‘Best Buy’ rating from Ethical Consumer, a joint top ranking in Which?’s 2024 eco energy review, and Uswitch Gold accreditation on all tariffs.

While only around 10 per cent of its gas is biogas, the rest is carbon-offset through international clean energy projects like biogas digesters in India and China.


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Octopus Energy

Octopus Energy is now one of Europe’s largest investors in renewable power, managing over 300 green energy sites in the UK and aiming to power 50 million homes worldwide by 2027. It sources electricity through Power Purchase Agreements (PPAs) with more than 190 UK-based renewable generators and has started developing its own sites, including wind turbines in East Yorkshire and South Wales.

Its Super Green tariff offers 100 per cent renewable electricity and carbon-offset gas, while its Smart Green tariffs incentivise using energy during periods of low carbon intensity. Octopus is especially popular with electric vehicle drivers thanks to its smart EV tariffs.

The Octopus Fan Club offers discounted energy rates – up to 50 per cent off to customers living near its wind turbines when the wind is strong. Octopus also topped Which?’s customer satisfaction survey in 2024 and holds a near-perfect 4.8-star Trustpilot rating.

However, in 2023, the company faced criticism from Friends of the Earth for funding a waste incinerator project in Scotland—something to be aware of if ethical sourcing is a top priority for you.


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SO Energy

SO Energy offers some of the most affordable renewable electricity tariffs in the UK, while still giving customers a voice in how their power is sourced. Launched in 2015, it is a smaller green supplier known for transparency and value. In 2021, it merged with Ireland’s ESB Energy to strengthen its green credentials.

SO Energy supplies 100 per cent renewable electricity and allows customers to vote annually on how their power is sourced – whether from wind, solar, hydro, or biomass – making it the only provider to offer this level of engagement.

The company pledges to keep its fixed tariffs among the best-value green options on the market, making it a strong choice for budget-conscious consumers looking to go green.


If you’d like to find out more about the above providers, a Which? membership gives you access to in-depth, expert reviews, ‘Best Buys’ and ‘Don’t Buys.’

Good With Money occasionally uses affiliate links to providers or offers, where relevant. This means that if you open an account or buy a service after following the link, Good With Money is paid a small referral fee. We choose our affiliates carefully and in line with the overall mission of the site.

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