Big Six energy suppliers
As of Q3 2019, the Big Six held a combined market share of 70% for electricity supply and 69% for gas supply in Great Britain. They previously held a combined market share across both markets of 100% in 2004.
In 2019, a complex merger and asset swap transaction meant that German power giant E.ON absorbed Npower. OVO Energy acquired SSE's domestic retail customers, effective January 2020, but will continue to use the SSE brand for the time being.
|Supplier||Customers in the UK (millions)||Parent||Other divisions and brands||Former brands|
|British Gas||15||Centrica||Scottish Gas|
|EDF Energy||5.7||Électricité de France||SEEBOARD, SWEB Energy, London Electricity|
|npower||6.5||E.ON||Innogy, Northern Electric, Yorkshire Electricity|
|Scottish Power||5.3||Iberdrola||PPM Energy||MANWEB|
|SSE||9.1||OVO Energy (since 2020)||Scottish and Southern, Southern Electric, SWALEC, Scottish Hydro|
2014–2016 competition investigation
In June 2014, energy market regulator Ofgem referred the energy industry to the Competition and Markets Authority (CMA). The authority investigated the "six large energy firms" and published its report in June 2016. For the retail market, the report recommended:
- Removal of the requirement imposed by the 2014 Retail Market Review that limited suppliers to offering no more than four tariffs
- Establishment by Ofgem of a database of customers who have been on a "standard variable tariff" for three years or more, which competitors could use to contact those customers
- A temporary price cap for customers on prepayment meters
- Measures to support price comparison websites in the energy market.
Consolidation to Big Five
Just after the failed SSE-Npower merger in late 2018, it was reported that a consolidation to the Big Five would still occur, as Npower would be acquired by default by E.ON due to the already-planned asset swap by the respective German parents, Innogy and E.ON. This was completed in 2019.
Alternatives to the Big Six
In December 2014, Utility Warehouse, part of FTSE 250-listed company Telecom Plus became the UK's biggest independent energy supplier through a £218m deal to buy 770,000 existing customers from npower. In September 2014, First Utility (since rebranded as Shell Energy) announced it was the first independent utility supplier to reach the milestone of 1m customer accounts for gas and electricity – the equivalent of 550,000 customers, which made it the seventh-largest energy supplier in the UK and the country's biggest independent energy provider. In June 2015, a Cornwall Report stated Opus Energy had broken the dominance of the 'Big Six' energy suppliers in the business market.
The Competition and Markets Authority published an investigation into the energy supply market in June 2016, following a referral by Ofgem in June 2014. The report identified 34 suppliers of both electricity and gas to households, and described the three largest suppliers outside the Big Six as "mid-tier suppliers"; these were First Utility, Ovo Energy and Utility Warehouse. Other significant suppliers (each with more than around 1% market share) were Co-operative Energy, Extra Energy and Utilita Energy (specialising in pre-pay customers). The combined market share of suppliers outside the Big Six had increased from less than 1% in 2011 to around 13% in the first quarter of 2016.
Since 2009, other entrants into the market include a number of new energy companies including Bulb Energy, Good Energy, Ecotricity, and Octopus Energy. Many of these newer entrants are seeing significant growth in customer numbers, in part due to their greater commitment to renewable energy and, in the case of Co-op Energy, community renewable energy projects.
Three of the alternative energy companies have been owned by local authorities. The first such company since 1948 was Robin Hood Energy, owned by Nottingham City Council, which entered the market in 2015. Bristol Energy, also launched in 2015, was owned by Bristol City Council. Both Robin Hood Energy and Bristol Energy were available to consumers throughout the country until their demise in 2020.
In January 2020, London Power was launched by the Mayor of London. Contrary to the other two companies, it only provides gas and electricity to London homes. London Power is not itself an energy supplier, instead it is a partnership between the Greater London Authority and a providing partner, currently Octopus Energy.
Defunct competitor companies
By January 2019, ten small energy suppliers had ceased trading or been taken over by others.
|Company||Ceased||Customers (approx.)||Customers transferred to|
|Affect Energy||September 2018||22,000||Octopus Energy (acquisition)|
|Breeze Energy||December 2019||18,000||British Gas|
|Brilliant Energy||March 2019||17,000||SSE|
|Bristol Energy||September 2020||155,000 domestic,
|Business: Yü EnergyDomestic: Together Energy|
|Economy Energy||January 2019||235,000||OVO Energy|
|ENGIE UK||January 2020||70,000||Octopus Energy (acquisition of ENGIE's domestic UK customers) |
|Extra Energy||November 2018||108,000 domestic,
|Flow Energy||May 2018||130,000||Co-op Energy (acquisition)
Brand continued until acquired by Octopus in 2019
|Future Energy||January 2018||10,000||Green Star Energy|
|GB Energy Supply||November 2016||160,000||Co-op Energy (acquisition)
Brand continued until acquired by Octopus in 2019
|Green Network Energy||January 2021||360,000||EDF|
|Green Star Energy||October 2019||200,000||Shell Energy (acquisition)
Green Star was a subsidiary of Canada's Just Energy
|Iresa||July 2018||100,000||Octopus Energy|
|OneSelect||December 2018||36,000||Together Energy|
|Our Power||January 2019||31,000||Utilita Energy|
|Robin Hood Energy||September 2020||112,000 domestic,
|Simplicity Energy||January 2021||50,000||British Gas Evolve|
|Solarplicity||August 2019||60,000||EDF Energy|
|Spark Energy||November 2018||290,000||OVO Energy|
|Tonik Energy||October 2020||130,000||Scottish Power|
|Toto Energy||October 2019||134,000||EDF Energy|
|Usio Energy||October 2018||7,000||First Utility|
|Yorkshire Energy||December 2020||74,000||Scottish Power|
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- "Ofgem appoints Utilita to take on customers of Our Power". Ofgem. 30 January 2019. Retrieved 5 May 2019.
- "Nottingham council 'sorry' as Robin Hood Energy collapses". BBC News. 4 September 2020. Retrieved 7 October 2020.
- "Simplicity Customers: Your questions on new supplier British Gas Evolve". Ofgem. 30 January 2021. Retrieved 13 February 2021.
- "Solarplicity customers: Your questions on new supplier EDF". Ofgem. 16 August 2019. Retrieved 18 August 2019.
- "Ofgem appoints OVO Energy to take on customers of Spark Energy Supply Limited". Ofgem. 27 November 2018. Retrieved 5 May 2019.
- "Ofgem appoints Scottish Power to take on customers of Tonik Energy Ltd". Ofgem. 9 October 2020. Retrieved 14 October 2020.
- "Ofgem appoints EDF Energy to take on customers of Toto Energy". Ofgem. 26 October 2019. Retrieved 29 January 2020.
- "Ofgem appoints First Utility to take on customers of Usio Energy". Ofgem. 18 October 2018. Retrieved 5 May 2019.
- Lempriere, Molly (7 December 2020). "ScottishPower takes on collapsed supplier Yorkshire Energy's customers". Current News. Retrieved 8 December 2020.