The Big Six

Who are the Big Six?

British Gas, EDF Energy, E.ON, npower, Scottish Power and SSE are the UK’s largest electricity and gas suppliers, more commonly known as the Big Six. Together, they account for 95% of the UK retail energy market.

Big Six market shares

British Gas is the largest electricity and gas supplier by far, with almost 32% of the electricity and gas retail markets. The next biggest energy supplier in the UK is npower with a market share of close to 16%, followed by Scottish Power (almost 13.7%), EDF Energy (13.4%), E.ON (12.2%) and SSE (8.5%).

Supplier

Market share

Customers (million)

British Gas Logo

31.7

13

EDF Energy Logo

13.4

5.5

e.on logo

12.2

5

npower logo

15.9

6.5

Scottish Power logo

13.7

5.6

SSE logo

8.5

3.5

Source: company websites.

What fuels do the Big Six use in their energy mix?

  • All suppliers except EDF Energy rely on coal for a substantial amount of their energy fuel mix, though Scottish Power has the largest coal component (59%).
  • Natural gas is also an important element in the Big Six fuel mix (again, except EDF Energy), though Npower relies on natural gas for over half of its energy mix (51%).
  • EDF Energy relies largely on nuclear energy (73.7% of fuel mix), which is only also important for British Gas (28%).
  • SSE has the largest component of renewable energy in its fuel mix (15%), closely followed by npower (14%) and Scottish Power (12.9%).

Source

British Gas Logo

EDF Energy Logo

e.on logo

npower logo

Scottish Power logo

SSE logo

Coal

26%

17%

52.2%

33.6%

59%

54%

Natural gas

34%

0%

30.7%

51%

25.6%

28%

Nuclear

28%

73.7%

4.7%

0.4%

1.3%

1%

Renewable

10%

8.3%

8.4%

14%

12.9%

15%

Other

2%

1%

4%

1%

1.2%

2%

Source: company websites.

How much do the Big Six charge for electricity and gas?

Although the standard tariff comparison rate imposed by Ofgem allows for a very basic price comparison of dual fuel offers for each of the Big Six, costs change according to usage and location so only a detailed comparison yields accurate prices. The following table only compares standard offers (with no contract end date or exit fees but variable prices) because the length of fixed price offers varies from one supplier to the other.

Supplier

Average cost per year*

British Gas Logo

£1,193

EDF Energy Logo

£1,164

e.on logo

£1,170

npower logo

£1,205

Scottish Power logo

£1,199

SSE logo

£1,186

Source: company websites.
*As of May 2014.

In terms of standard price comparisons, EDF Energy appears to be the cheapest supplier among the Big Six. It is closely followed by E.ON, then SSE, Scottish Power and npower.

How good is customer care among the Big Six?

Proportionally, Scottish Power customers complain the least. Interestingly, Scottish Power is also the supplier that takes the longest to resolve complaints. Npower is the supplier whose customers complain most but it resolves them considerably faster. Customers complain overwhelmingly about billing issues, exept E.ON customers, who complain mostly about customer service.

 

British Gas Logo

EDF Energy Logo

e.on logo

npower logo

Scottish Power logo

SSE logo

Number of complaints per 100,000 accounts*

3,084

4,614

3,276

8,303

1,357

2,760

Percentage of complaints resolved within one working day*

79.5%

84%

87.8%

85.4%

50%

82.11%

Object of most complaints

Billing

Billing

Customer service

Billing

Billing

N/A**

*First quarter 2014 (January-March)
**SSE does not make complaints categories available.

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Find out all about the six largest electricity and gas suppliers in the UK: prices, fuel mix, customer reviews.