Electricity suppliers: the price cap, green claims, and service

This guide covers household electricity in Great Britain: England, Scotland and Wales. Northern Ireland has its own regulator, the Utility Regulator, so the Ofgem rules below do not cover it. If you live in another country, your market has its own rules, so treat this as a way of asking questions rather than a list of answers.

Whoever you pay, the electricity reaching your home comes from the same national grid. What changes is the price you pay, where your supplier's money goes, and how you are treated when something goes wrong.

The short answer. Most suppliers' standard tariffs sit under the same Ofgem price cap, so none of them can charge above the same limits. The real differences are green claims and service. Many "100% renewable" tariffs rest on certificates that, on their own, do not add new generation. Three suppliers, Good Energy, Ecotricity and 100Green, may charge above the cap on their renewable tariffs, and Ofgem says it has not judged whether those tariffs are good value. Check the Citizens Advice star rating before you switch.

The data, at a glance

How strongly each supplier's electricity supports renewable generation:

Weigh what you care about

Price (Great Britain). Ofgem sets the price cap every three months. It limits what a supplier can charge per unit of energy and in standing charges on standard variable tariffs; it "does not limit the cost of your total bill," and it does not apply to fixed deals. Ofgem has let Good Energy, Ecotricity and 100Green charge above the cap on their renewable standard variable tariffs, and says in each decision that it has "not assessed whether these tariffs provide good value to consumers."

What "green" means. British Gas explains that you cannot trace renewable electricity to a particular home, so suppliers buy certificates called Renewable Energy Guarantees of Origin (REGOs) to show that an equal amount was fed into the grid. OVO, which stopped using REGOs as standard in 2023, says plainly that "REGOs don't actually make the UK electricity grid any greener." Utilita goes further: "there's no such thing as a 100% renewable tariff."

Some suppliers go past certificates. Octopus says it buys through power purchase agreements with more than 700 UK generators and has about £6 billion in renewable assets. Good Energy says it buys from over 3,300 British generators and matched supply with generation in real time 87 percent of the time from April 2025 to March 2026. 100Green says it holds a REGO for every megawatt hour it supplies and that Ofgem audits the process each year.

Fuel mix. Suppliers publish these each year, for different periods, so compare like with like:

A low share can mean a supplier stopped buying certificates, as OVO did, so read the explanation beside the number.

Service. Citizens Advice rates suppliers with more than 25,000 accounts on complaints, contact waiting times, billing and metering, and commitments. For April to June 2026, Outfox Energy scored highest at 4.03 out of 5, followed by 100Green (3.90), E.ON Next (3.71), Good Energy (3.68) and Octopus (3.67). British Gas scored 2.61 and TruEnergy was lowest at 1.38.

If you care most about...

There is no single best supplier. The cap-exempt green suppliers can cost more, and a cheap supplier with poor service can cost you hours.

The switch you may not need

If you are on a standard variable tariff, the cap already protects the unit price. Using less electricity lowers any bill without switching. Community energy schemes and home solar are separate decisions on this site.

Before you switch

Ofgem says a switch must happen within 5 working days, or your new supplier pays you £40. You can cancel within 14 days. Leaving a fixed tariff early may bring an exit fee. If you have owed money for more than 28 days you may not be able to switch, though prepayment customers with debt up to £500 can. We give no financial advice; Citizens Advice can help with your case.

What we're not telling you

We do not list current prices, which change every quarter and by region and payment method. Fuel mix figures are suppliers' own disclosures. Star ratings cover one quarter at a time; ours are for April to June 2026.

How we made this

We take no money from energy suppliers. Every claim above comes from a page we opened in September 2026. If something has changed, tell us through Contribute and we will correct it.

Sources

• Utility Regulator (Northern Ireland), checked 2026-09
• Ofgem, energy price cap and standing charges explained, checked 2026-09
• Ofgem, monitoring of derogated renewable tariffs, checked 2026-09
• Ofgem, Good Energy derogation decision, checked 2026-09
• Ofgem, Ecotricity derogation decision, checked 2026-09
• British Gas, energy sources, checked 2026-09
• OVO, fuel mix, checked 2026-09
• Utilita, sustainability, checked 2026-09
• Octopus Energy, green, checked 2026-09
• Good Energy, our energy, checked 2026-09
• 100Green, FAQs, checked 2026-09
• E.ON Next, fuel mix, checked 2026-09
• EDF, fuel mix, checked 2026-09
• Citizens Advice, compare energy suppliers' customer service, checked 2026-09
• Ofgem, switch your home energy supplier, checked 2026-09

Compare suppliers on price, renewable investment, clarity and service by your own weighting in the electricity-suppliers explorer.