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Energy Suppliers

Switching energy suppliers is one of the quickest, easiest, and sure-fire ways to save money on your energy bills. But choosing the right one for your household and its specific needs isn’t as simple. There are many energy suppliers to choose from, each offering varying ranges of tariffs, levels of customer service, and fuel mixes.

Lauren Smith
Mike Rowe
Written by Lauren Smith
Edited by Mike Rowe
04 November 2025
7 mins read

Why compare suppliers?

It’s important to put some thought into choosing your new energy supplier. Not only do you want the cheapest deal for your requirements, whether that’s the tariff with the lowest unit rates or one with little to no standing charge, but you should also consider their reputation, contract terms, and where they source their energy from, whether it’s from renewables or fossil fuels or a mixture of both. In today’s world, consumers are increasingly mindful of their carbon footprint, and luckily, securing a green energy tariff can also save you money on your bills.

To help you with your energy comparison, we’ve compiled a list of the UK’s main energy suppliers - the ones you’ll be offered quotes from when comparing with us - to give you a better idea of who they are and what they offer.

Which energy suppliers operate in the UK?

There are currently around two dozen energy suppliers operating in the UK, some of them supplying gas and electricity to millions of households across the country, while some smaller, independent ones supply energy to just a few thousand. We compare tariffs from all energy suppliers, whether it’s those in the so-called ‘Big Six’ or smaller competitors.

The Big Six

With a combined market share of around 91%, the ‘Big Six’ energy suppliers dominate the gas and electricity market in the UK. Let’s take a look at who they are:

British Gas

Arguably the most well-known domestic energy supplier in the UK, British Gas supplies gas and electricity to around 7 million households, or more than 20% of the country, as well as over 400,000 businesses.

Founded over two centuries ago, British Gas has had plenty of time to build its reputation, and today it is a household name.

However, its reputation isn’t all good, and it typically receives less-than-average customer satisfaction scores, but it offers an extensive range of tariffs to suit almost any type of household.

EDF Energy

A subsidiary of French utility company EDF Group, EDF Energy is one of the largest gas and electricity suppliers in the UK, boasting around 5.5 million domestic customers.

It’s also a fairly green supplier, with a significant amount of its fuel coming from nuclear energy - more than any other supplier in the UK.

It offers a wide range of tariffs, although it isn’t widely regarded as being good value for money. However, it does have a great reputation when it comes to supporting vulnerable customers, such as the elderly and those struggling to pay their bills.

E.ON/E.ON Next

Another of the UK’s leading energy suppliers, E.ON is the third-largest electricity provider in the UK, although its parent company - E.ON Group - is headquartered in Germany. Its domestic supply branch in the UK - E.ON Next - supplies more than 5 million households with gas and electricity, growing significantly after its acquisition of former Big Six supplier npower in 2019.

It claims to focus on innovation, smart energy solutions, and sustainability, and it offers customers many tools to support themselves in this regard, but it doesn’t have the best reputation for value for money.

Octopus Energy

One of the fastest-growing energy suppliers in the UK, Octopus Energy was only founded in 2015 but has since gone on to shake up the country’s domestic supply market.

Focusing on ‘fair, clean, and simple’ energy, Octopus Energy has a rapidly growing customer base, and after taking on Bulb Energy’s customers and acquiring Shell Energy in 2023, it has grown to become the UK’s leading electricity supplier, providing power to around 7.3 million households today.

It also has a reputation that’s the envy of some other suppliers, consistently ranking high for customer satisfaction with service and bill accuracy, while 100% of its energy comes from renewable sources.

OVO Energy

Another supplier that has managed to break into the Big Six in recent years is OVO Energy, which took over former Big Six supplier SSE Energy in 2020.

Having started out in 2009, it now supplies energy to over 4.5 million domestic households across the UK.

Like Octopus, OVO Energy also has a strong focus on renewable energy and it has steadily reduced its reliance on fossil fuels over the years. It also offers the ‘Path to Zero’ plan, which helps customers reduce their carbon footprint with expert energy advice on efficiency and insulation solutions.

Scottish Power

The final supplier to make up the Big Six is Scottish Power, which supplies energy to more than 5 million households and businesses across the UK.

Part of the global Iberdrola Group, Scottish Power is also a significant energy generator, with renewable wind farms dotted around the country, supplying electricity to the National Grid.

While not 100% renewable, it does offer 100% green tariffs, although it’s had issues with customer service in the past.

Other suppliers

When looking for the best energy deal, it’s important to consider all quotes offered to you, and not just those from the Big Six or names you’ve heard of. Many smaller, independent suppliers offer very competitive tariffs that may be best suited to you, while smaller customer bases typically allow for a greater level of personal customer service. However, this may not always be the case, so it’s worth doing a bit of extra research on any supplier you’re not familiar with.

Other energy suppliers you may find quotes from include:

  • 100Green

  • Co-op Energy

  • Boost

  • Ecotricity

  • Good Energy

  • Sainsbury's Energy

  • So Energy

  • Utilita

  • Utility Warehouse

Which is the cheapest energy supplier?

Unfortunately, there’s no single answer to this question, as the market is constantly changing, and the cheapest energy supplier for one household may not be the same as the cheapest supplier for another.

Ultimately, the amount you pay for your gas and electricity each month depends on the amount of energy you actually consume.

If you live in a high-usage household, it’s wise to choose a tariff with low unit rates, which will typically have a higher standing charge. On the other hand, low-usage households would be better off with a tariff offering low standing charges but higher unit rates.

At the end of the day, the only way to find out who the cheapest energy supplier for you is to run an energy comparison, weighing up unit rates and standing charges against your typical annual usage to calculate how much your bills should be.

Who is the greenest energy supplier?

There isn’t a definitive answer to this, either, as a number of energy suppliers now claim to be 100% green, but what they mean by this may vary somewhat.

Typically, if a supplier claims to be 100% green or 100% renewable, this means that all of the energy they supply comes from renewable sources, such as solar, wind, or hydropower.

However, other suppliers may use what’s known as ‘carbon offsetting,’ in which they promise to invest in carbon capture technologies or tree planting as a way to balance out the emissions they produce in their energy generation.

That being said, a number of energy suppliers in the UK are fully committed to renewable energy solutions and can actually be called ‘100% green.’ These include 100Green, Ecotricity, and Octopus Energy.

You’ll also find some kind of green tariff from most suppliers these days, and you can check each supplier’s green credentials by looking at their fuel mix, which can be found on their individual websites or their pages on our website.

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