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Around 20 active domestic suppliers compete for UK households today, and the price gap between them runs into hundreds of pounds for the same kWh consumption. Loyalty is the quietest way to overpay.
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Looking for the right supplier? Browse profiles for every active UK gas and electricity provider below. Each card links to a detailed guide covering tariffs, contact details and reviews.
Major UK energy providers
These are the suppliers that dominate the domestic UK energy market, including the Big Six (Octopus Energy, British Gas, E.ON Next, OVO Energy, EDF Energy and Scottish Power) and the largest challengers outside that group. Click any logo to see tariffs, contact information and customer reviews.
Energy providers: a brief history
According to the most recent Ofgem licensee data, around 20 active companies supply gas or electricity to domestic households in Great Britain, down from a peak of more than 70 before the 2021 wholesale price spike. Suppliers fall into three broad categories:
- Dual-fuel energy providers (both gas and electricity); this is now the standard model and covers all of the Big Six.
- Electricity-only providers such as Ecotricity, which historically focused on green power generation.
- Gas-only providers; a small niche today, with most former gas-only entrants having either exited the market or expanded into electricity.
Electricity providers
The electricity sector was privatised in Great Britain in the early 1990s. The aim was to promote competition among companies and protect consumer interests. By 2005, just six electricity providers (the original "Big Six": British Gas, E.ON, EDF, npower, Scottish Power and SSE) supplied 99% of households.
Their 99% grip on the electricity market lasted until around 2014, when challenger brands began to take share. By 2020 the smaller suppliers collectively held over a quarter of the market. The 2021-2022 energy crisis then forced more than 30 suppliers out of business, while a wave of acquisitions reshaped the top of the table: Octopus Energy absorbed Bulb in 2022 and Shell Energy's UK retail business at the end of 2023, overtaking British Gas to become Great Britain's largest domestic supplier.
Gas providers
National gas supplier British Gas was created in 1972. It was then privatised in 1986 under Margaret Thatcher. The 'Tell Sid' campaign encouraged individuals to buy shares in the company. With an IPO of 135p per share, British Gas was valued at £9 billion; at the time the highest equity offering ever.
The same group of companies came to dominate the gas market in the UK. As with electricity, the Big Six supplied around 99% of the gas market until 2014. British Gas remains the single largest domestic gas supplier today, though Octopus Energy has closed the gap and now holds a comparable share.
Who has the biggest share of the UK energy market?
Below is a breakdown of the UK domestic gas and electricity markets, based on the latest Ofgem retail market data. The Big Six suppliers together account for around 92% of all domestic accounts, with Octopus Energy leading the electricity market and British Gas still narrowly leading on gas. Bars show each supplier's share as a percentage of the total market.
Electricity market share
- Octopus Energy 24.6%
- British Gas 20.9%
- E.ON Next 15.7%
- OVO Energy 12.2%
- EDF Energy 10.2%
- Scottish Power 8%
- Other suppliers 8.4%
Gas market share
- British Gas 27.2%
- Octopus Energy 25%
- E.ON Next 13.3%
- OVO Energy 10.4%
- EDF Energy 8.6%
- Scottish Power 7%
- Other suppliers 8.5%
Note: shares reflect the post-consolidation market. SSE's domestic supply was acquired by OVO Energy in January 2020; Npower's residential customers were transferred to E.ON Next in 2019-2021; Bulb Energy was taken over by Octopus Energy in December 2022; Shell Energy's UK home retail business was acquired by Octopus Energy at the end of 2023; and Boost was folded back into OVO Energy in late 2024. "Other suppliers" covers the remaining ~14 active brands, including Utilita, Utility Warehouse, So Energy, Good Energy, Ecotricity, 100Green, Outfox the Market, Sainsbury's Energy and E (Gas & Electricity).
Which are the best-rated energy providers?
While price is often the most important factor people examine when choosing an energy provider, it's also a good idea to consider the quality of the company's customer service.
Citizens Advice compares UK energy providers in terms of customer service on a quarterly basis. The organisation rates suppliers across the following categories:
- Average call-wait time.
- Number of complaints per 10,000 customers.
- Customers that received an accurate bill during the past year.
- Bills and statements issued on time.
- Switches completed within 21 days.
- Customer guarantees.
For the most up-to-date Citizens Advice supplier league table, head to the Citizens Advice star rating tool.
Renewable energy providers
Each year, all energy companies are required to disclose the different fuels from which they source electricity. Being with a renewable energy supplier does not mean that the actual electrons you consume are 100% renewable. All generated electricity goes into the same grid before being distributed to homes. However, suppliers with green or renewable tariffs match customer demand with Renewable Energy Guarantees of Origin (REGO) certificates and, in the strongest cases, with direct Power Purchase Agreements (PPAs) signed with UK wind, solar and hydro generators.
Independent reviews (Which?, Ethical Consumer) consistently rate Good Energy, 100Green and Ecotricity as the most credible green suppliers because they back their tariffs primarily with PPAs and their own generation rather than REGO-only sourcing. Octopus Energy, the UK's largest supplier, also backs all of its electricity tariffs with 100% renewable power.
The active providers below offer 100% renewable electricity tariffs as standard or as an option:
Prepayment (PAYG) energy providers
Around four million households use prepayment meters in Great Britain, roughly 13% of all households. Most legacy prepay-only brands have been absorbed into their parent groups (Boost was folded into OVO Energy in late 2024) so today's pay-as-you-go market is served mainly by the Big Six and the prepayment specialists Utilita and E. The active suppliers offering PAYG tariffs for new customers are:
Business energy providers
Alongside the domestic market, several providers specialise in business energy for SMEs and larger commercial sites. Unlike domestic tariffs, business energy rates are rarely published online; you'll usually need to contact the supplier or a broker directly for a personalised quote. Note that the business-energy market has consolidated significantly in recent years too: Opus Energy stopped writing new contracts when EDF took over its non-domestic book in September 2024.
For more on the most popular business energy providers, head to their guide:
Who is my current energy supplier?
Your energy supplier is the company you pay either your power or gas bill to. You can find out who your energy provider is in the following ways:
- Take a look at your energy bill. You've likely received bills (or a welcome pack for prepayment customers) from your energy provider; its name should be on the documents.
- Check your email. If you signed up for paperless billing, your provider will send all your information by email. Try searching for "energy" in your inbox.
- Contact your DNO. Your Distribution Network Operator (DNO) varies depending on where you live. Head to our DNO guide to find out who yours is.
- Check your bank statements. Whether online or paper, your energy provider's name should appear on your bank statements.
If you're still having trouble, head to our dedicated guide on finding your energy supplier.
How do I choose a gas and electricity supplier?
When choosing an energy provider for your home, there are a few different factors we recommend you consider. While some of these factors may seem obvious, others, just as important, are easily overlooked.
- Cost. Is it a good deal? To decide, always take into account your own energy use.
- Customer service. Can you count on the energy company to provide high-quality customer support?
- Energy sources. Are you interested in doing your part to help save the planet? Choose an energy provider that has 100% renewable tariff options.
- Exit fees. Will you be charged a fee for terminating your contract early? You may want to find an energy tariff without any exit fees if you're only planning to stay at the property for a limited time.
Before starting to compare plans, we recommend you establish your priorities so that you can find the best energy provider to suit your needs.
Every active UK energy supplier
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