Big Six energy suppliers

The Big Six were the United Kingdom's largest retail suppliers of gas and electricity, who dominated the market following liberalisation in the late 1990s. By 2002, six companies – British Gas, EDF Energy, E.ON, RWE npower, Scottish Power and SSE – had emerged from the 15 former incumbent monopoly suppliers (the 14 regional public electricity suppliers and British Gas).[1]

In 2008, the Big Six still had over 99% of domestic and small business customers.[1] They were vertically integrated in electricity, owning sufficient generation capacity to supply all their customers; while in gas, only Centrica (British Gas) owned production facilities.[1] By the third quarter of 2019, after efforts by the regulator Ofgem to promote competition, their combined share in Great Britain was 70% for electricity supply and 69% for gas.[2][3] The purchase of SSE's retail business in January 2020 by OVO Energy, a competitor founded in 2009, marked the end of the original Big Six.[4]

  1. ^ a b c "Energy Supply Probe – Initial Findings Report" (PDF). Ofgem. 6 October 2008. pp. 27–30. Archived (PDF) from the original on 31 October 2008. Retrieved 1 November 2021.
  2. ^ "Electricity supply market shares by company: Domestic (GB)". Ofgem. 1 January 2020. Archived from the original on 6 February 2020. Retrieved 6 February 2020.
  3. ^ "Gas supply market shares by company: Domestic (GB)". Ofgem. 1 January 2020. Archived from the original on 6 February 2020. Retrieved 6 February 2020.
  4. ^ "New UK energy giant created in SSE-Ovo deal". BBC News: Business. 13 September 2019. Retrieved 16 September 2019.