The Big Six Energy Suppliers

Who were the big six energy suppliers?

Until recently, just six firms supplied gas and electricity to over 90% of the UK’s households. These companies were known as the ‘big six’.

A series of mergers, and increased competition, shifted this landscape a bit. Now Ofgem simply uses the term ‘large suppliers’ to refer to the firms with the largest market share – a category which now goes beyond six.

But who are these suppliers? How much do the former big six still dominate? And, more importantly, are you better trusting one of them with your energy supply, or choosing a smaller firm? Read on to find out.

Who were the big six?

The big six were the largest energy companies in the UK:

• British Gas
  • British Gas is the UK’s largest energy company and is the greenest supplier of the big six.
• EDF Energy
  • EDF Energy is the UK arm of the French energy giant EDF, and supplies more than 5.5 million customers.
• E.ON
  • E.ON (formerly Powergen) is another European entrant in the UK energy market, and currently serves around 7 million customers.
• npower
  • npower is the smallest of the big six, and outside of domestic supply is focusing on expanding wind and hydro-electic power. In 2019, npower was bought out by E.ON.
• Scottish Power
  • Scottish Power is the next largest above npower, and supplies energy to around one in every ten UK households.
• SSE
  • SSE was the second largest energy supplier in the UK, and the second best for renewable power. In 2019, SSE was bought by challenger supplier OVO, which continues to operate tariffs under the SSE brand for now.

Big six market share

Between then, the big six accounted for over 90% of the UK’s domestic energy supply until around 2014 (source: Ofgem). In recent years, more and more customers have switched over to smaller suppliers, and by 2019, the big six held 70% of the market.

Now, 10 suppliers share 87.5% of the market, and the share held by ‘smaller suppliers is sitting at around 8%.

Why aren’t more people switching supplier?

Politicians have continuously called for people to look around for cheaper electricity and gas deals. In spite of this, under half of the households in the UK have ever changed their gas or electricity supplier.

Many people believe it is very difficult to switch energy supplier; that it takes a long time or that they would need to lay new pipes or cables before they would be able to. However this just is not the case. Switching energy supplier doesn’t need to take more than five minutes.

All you need to do to switch is tell us your postcode and your energy usage. With this information we can present you with a list of all the best gas and electricity deals that are available to you.

If you choose to switch by using our energy comparison tool, you won’t experience any interruptions to your power supply at any point. You also won’t need any new pipes or cables put into your house. This is because all energy suppliers deliver their energy in the same way, the only thing that changes is who supplies it and how much you pay for that supply.

Should I switch to a small supplier?

There are many small energy suppliers out there who offer a viable alternative to those companies in the big six. In fact many of these companies have much higher levels of customer satisfaction than the companies in the big six.

The main concern that people express, when they are asked about switching energy to a smaller supplier, is that they might be left high and dry if the small supplier were to go out of business. However, this is not a concern that you need to have.

Ofgem, the regulator for energy in the UK, has put in place measures to protect you from losing your energy supply if your supplier goes under. This means that no matter what happens you will always receive a steady supply of energy to your household. If your current supplier can no longer provide you with energy, you will simply be switched to another supplier that can.