Energy Fuel Mix Guide

Fuel Mix

What’s in this guide?


Did you know that depending on your energy supplier, your energy could be coming from a different place?

Although most energy suppliers use a combination of fossil fuels such as gas and coal, some purchase their electricity from renewable generators.

That means it’s better for the planet, and sometimes better for your wallet.

Let’s take a look at fuel mixes, including what it is, which suppliers have what kind of fuel mix and the national average.

Read on and find out more.

What is a fuel mix?

A fuel mix refers to the blend of fuel that energy suppliers use to supply your energy. For instance, see the table below for Octopus Energy’s fuel mix and the comparison to the UK average.

Since 2005, it has been a legal requirement for your energy company to tell you what their fuel mix is so that you can make an educated decision about your energy.

This is particularly important if you care about having green energy or investing in renewable energy generation.

You can often find your energy suppliers fuel mix on their website. Usually under a tab or on the front page.

In each instance, you can compare it to the UK average.

This tells you how your energy company matches up to the UK average, which typically consists of approximately 24% renewable energy, 23% nuclear energy and 17% coal.

Typical example

Below you can see the fuel mix for Octopus Energy, which was awarded Which? Recommended Provider in 2018.

Although they do offer a 100% green energy option, their fuel often consists of this mix:

Energy Source

Octopus Energy

UK Average

Coal 1% 17.00%
Natural gas 1% 32.30%
Nuclear 1% 23.70%
Renewables 97% 24.30%
Other fuels 0% 2.50%
CO2 emissions 13 g/kWh 290 g/kWh
High-level radioactive waste 0.00004 g/kWh 0.0017 g/kWh

So why is this so important? Let’s find out.

Why is it important?

Knowing your fuel mix is essential because it can help you understand the impact that your energy makes.

For instance, a good example is that if you use natural gas, you are paying for a natural gas-fired plant to produce your electricity. This is far more environmentally friendly than using coal for the same purpose.

As you can imagine, the higher your supplier’s renewable energy percentage, the greener your energy is.

Renewable energy comes from sources such as solar power, hydro, wind power or biomass.

The actual electricity you get won’t be different from anyone else, you will still get a steady and reliable stream that powers your home perfectly.

The only real difference is where your money is going.

Plus, when choosing green energy, you can rest easy that you’re helping to develop the UK’s switch to renewables.

List of energy suppliers and their fuel mix

See the table below for more information about some energy suppliers and their energy usage.

This can help you make more of an informed decision about your energy supplier. Especially if you want to switch to a greener option.

Fuel Mix Disclosure Data

Supplier Coal Gas Nuclear Renewable Other CO2 Nuclear waste
Affect Energy 13.5 41.4 11.3 29.4 4.4 0.298 0.00079
Angelic Energy 13.5 41.4 11.3 29.4 4.4 0.298 0.00079
Breeze 13.5 41.4 11.3 29.4 4.4 0.298 0.00079
Brighter World 13.5 41.4 11.3 29.4 4.4 0.298 0.00079
Bristol Energy 11 35 9 41 4 0.25 0.00063
British Gas 11 35 10 40 4 0.252 0.0007
Bulb 0 0 0 100 0 0 0
Co-operative Energy 6.7 20.4 5.6 65.2 2.2 0.147 0.00039
E 10.6 32.6 8.9 44.5 3.5 0.234 0.00062
E.ON 13.5 41.4 11.3 29.4 4.4 0.298 0.00079
EBICo 9 56 5 27 3 0.298 0.00038
Economy Energy 8.5 44.1 21 24.2 2.2 0.254 0.00147
Ecotricity 0 0 0 100 0 0 0
EDF Energy 5.7 8.4 76.9 8.8 0.3 0.084 0.0054
Energy SW 0 35.3 0 64.7 0 0.127 0
Engie 5 53 2 39 0.8 0.249 0.00013
Extra Energy 14 41 11 29 4 0.298 0.00079

Top green energy companies

For an idea of the top electricity suppliers, this is a list of some of the most popular and highest rated energy suppliers on Trustpilot, with a rating of 4-stars and above.


Bulb Logo

Bulb Energy is a newer energy company, having been launched in 2015 by two industry experts. They wanted to offer a more open energy company.

This fresh approach to energy has to lead to thousands of customers leaving 5-star reviews on Trustpilot, claiming that the company is ethical, well-priced and helpful.

So Energy

So Energy

So Energy claims to give their customers great value as well as giving you control over where your energy comes from. This means either solar, wind, biomass, hydroelectric or tidal and their Ofgem report will reflect what their customers have chosen.


Affect energy logo

Affect is a business that has a team with over 50 years of experience with one of the bigger energy companies, and in that time they discovered that what people want is simple.

Affordable prices, and for their energy supplier to do what they say they are going to do.

So that’s what their aim is, and according to their high customer reviews, they are succeeding.


Boost logo

Boost Power is a subsidiary of OVO Energy, which is a favourite independent energy company in the UK.

Created to serve prepayment customers of OVO, but they also welcome new customers. In a move to make sure that OVO’s prepayment customers have the dedicated support team they deserve.


Did you know that you could be saving up to £500 on your energy bills every year?

Take a look at the EnergySeek guides to find out more about your energy, or see reviews of the top 7 energy switching sites to compare gas & electricity.