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Who are the six biggest energy companies?

on October 23 | in All, Other | by | with No Comments

Origins of the UK’s six biggest energy companies can be traced back to 1989 when the Electricity Act was introduced. This broke up the Central Electricity Generating Board into three generating companies and one transmission firm, that were privatised in the 1990s. The gas market was privatised in 1986 too and these combinations, separation and privatisation of supply resulted in the big six energy companies who control around 95% of the UK’s energy supply. This is who they are:

British Gas

Originally formed in 1973, the British Gas Corporation was privatised in 1986 and floated on the stock market as British Gas PLC. Then in 1997 it was brought under the ownership of Centrica and has grown to become the largest supplier of gas in the country with 11 million customers. Plus, it supplies electricity to a further six million.

EDF Energy

EDF Energy was founded in 2002 after the acquisition and merger of various regional and national energy companies. It is owned by the French state-controlled EDF and also acquired nuclear generator British Energy back in 2009. Currently EDF Energy provides gas and electricity to six million people in the UK.

Green energy representation

Green energy representation


Formerly known as Powergen, it became E.ON in 2007 after being acquired by E.ON AG, a German energy company. With around seven million customers in total across the UK, it is the third largest energy provider, employing around 12,000 staff and 79,000 across the world.


First known as National Power and emerging after the 1989 Electricity Act, it then became Innogy PLC in 2000 and was demerged. Until 2002 when German utilities company RWE bought it and rebranded as npower. It currently has around five million UK customers and has previously operated under Northern Electric and Yorkshire Electricity.

Scottish Power

After the privatisation of Scottish energy supply in 1990, Scottish Power emerged. It was then acquired by Spanish energy company Iberdrola in 2006, under Europe’s third largest energy company. It has about five million customers across all of the UK, and still owns a big percentage of Scotland and the north of England’s distribution network.


Scottish and Southern Energy (SSE) is the UK’s second largest provider of electricity, with around nine million customers. It was formed after the merger of Scottish Hydro and Southern Electric, before incorporating South Wales Electricity Board (Swalec) later on.

Along with the big six, there are many smaller energy firms that households can turn towards. Comparing energy suppliers with Utilitywise in your area can help you find the cheapest option, whether it’s with one of the big six or someone else.


A light bulb

A light bulb

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