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A guide to the Big Six energy suppliers

The ‘Big Six’ are the largest energy suppliers in the UK. Find out a bit more about them and see if bigger means better when it comes to choosing where your energy comes from.

Sofia Hutson

Energy expert

minute read

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Posted 16 JANUARY 2020 Last Updated 1 JUNE 2021

Who are the Big Six?

The ‘Big Six’ is the collective name given to the six biggest energy suppliers in the UK.

Despite being pretty dominant since 1989’s privatisation of the energy sector, there have been various mergers and break-ups since – and the picture is now changing once again. In fact, two major recent takeover deals will eventually see the end of both the SSE and npower brands.

As of February 2021, the ‘Big Six’ energy brands remain:

British Gas
SSE (now owned by Ovo Energy, details below)
E.ON
EDF Energy
npower (now owned by E.ON, details below)
Scottish Power

Collectively, the Big Six supply gas or electricity to approximately 72% of homes in the UK.

But as more independent suppliers vie for a share of the market, the dominance of these major players is under increasing threat.

Your guide to the Big Six energy suppliers

British Gas is the UK’s largest energy provider, supplying gas and electricity to more than 11.6 million homes, with a wide range of tariffs available. It’s owned by parent company Centrica.
SSE sold its retail arm to Ovo Energy in January 2020, which included its energy customers, although the brand still remains. As contracts run out, SSE customers will be switched over to the Ovo brand. The takeover means that Ovo now supplies energy to around five million households in the UK.
E.ON, previously known as Powergen, powers about 3.8 million households in the UK and has a strong focus on innovative technologies. In fact, all its customers’ homes are powered with 100% renewable electricity. In early 2019 it took control of npower and is in the process of switching its customers over to the E.ON brand.

EDF Energy provides energy to more than 3.5 million homes and businesses and is the UK’s largest provider of low-carbon electricity. It’s the UK subsidiary of a French state-owned energy company called Electricite de France.
npower supplies around 3.6 million UK homes and businesses with gas and electricity. It’s now part of the E.ON group and will eventually cease to operate under the npower name.
Scottish Power provides energy to around five million homes and businesses in the UK. It’s now owned by Spanish energy firm Iberdrola and generates electricity from its own wind farms.

Is it a good idea to stick with one of the Big Six?

The Big Six aren’t always the cheapest option when comparing energy prices, although bigger companies can sometimes afford to be more competitive with their pricing.

Energy is energy. Regardless of who you buy it from, it will come to your pipes and switches the same way. Which provider you choose is all down to personal preference, cost and customer service.

The Big Six are big because they have the most customers – but much of this is due to how long they’ve been around for, or which companies they’ve merged with, rather than because they deliver the best service and prices. These days more of our customers seem to be switching away from the Big Six rather than to them. See who the biggest winners and losers are in switching in our latest Energy Snapshot.

See our Energy Snapshot

How do I find an alternative to the Big Six?

If you don’t want to go with one of the Big Six, there are plenty of other options, so don’t worry about going against the grain. In the past, alternatives to the main players have been relatively small scale rivals. But with a rising number of big name disrupters coming into the frame – including Ovo Energy and British Gas Evolve – energy customers are being given real food for thought.

These ‘large suppliers’ (those classed by Energy UK as having a market share greater than 5%) are growing in number, and now class among their ranks Bulb Energy and Octopus Energy – the new frontrunners in the charge against the traditional elite.

There’s also a whole raft of less-established companies to choose from, many of whom have much higher levels of customer satisfaction than the Big Six, as you’ll see if you compare with us.

In June 2020, smaller energy suppliers that customers switched to through Compare the Market included:

Together Energy
Igloo Energy
Utility Point
So Energy
Avro Energy

While EDF had the tariff that saved customers the most money overall, Igloo and Together Energy made it into the top five highest-saving tariffs found through Compare the Market in June.

Some providers are dedicated to sustainable sourcing and green energy, so if you’re looking for an eco-friendly supplier, there are plenty of options.

Why don’t more people switch energy suppliers?

Between January and October 2020, a total of one million gas customers and 1.3 million electricity customers switched to a smaller supplier, according to Ofgem, the regulator for energy in the UK. While this represents 28% of total switches, there still seems to be a reluctance among Brits to change supplier, especially to a company that’s less well-known.

Some customers are put off because they mistakenly believe they’ll need to have new cables and pipes installed, while others don’t think the savings will be worth it.

One of the main worries you might have if you’re thinking of switching to a smaller supplier is that you’d be left without heating and hot water if they were to go out of business. That’s obviously something no one wants. But Ofgem has put in place measures to protect customers from losing their energy supply if their provider collapses. This safety net means you’d automatically be switched to another company appointed by them if that happened.

How do I switch energy providers?

Whether you’re moving to or from one of the Big Six providers, changing gas and electricity supplier is simple with Compare the Market. You’ll just need to have your latest bill to hand and tell us where you live. Why not start a quote online today and see if you could start saving?

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