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Fuel Mix

What is fuel mix and why does it matter?

Fuel mix is simply a record of the sources of energy used by an energy supplier in generating the electricity they supply to their customers.

It isn’t a league table standing in judgment on supplier A, B or C. Rather it is a transparent reporting methodology that allows customers to understand the sources of their energy supply and enables them to make commercial judgments based on this data if they should so wish.

The UK’s latest fuel mix

Published by DECC on 31st July 2014, the 2013/14 UK fuel mix was:

Energy Source%
Other  2.1

Visit our supplier fuel mix guide to see how the suppliers’ fuel mix performance compares.

Where did Fuel Mix come from and when?

The Electricity (Fuel Mix Disclosure) Regulations 2005 was a statutory instrument laid before parliament by the DTI (now DECC) in February 2005 and coming into force in March 2005. It was prompted by the EU’s ‘Internal Market In Electricity Directive’ of 1st July 2004.

What does the regulation require?

The Electricity (Fuel Mix Disclosure) Regulations 2005 requires any organization holding an electricity supply licence to submit their fuel mix data to DECC in order for them to produce the “fuel mix disclosure data table”.

The “disclosure period” runs from 1st April to 31st March each year.

The “fuel mix disclosure data table” is then published by DECC on 1st August each year.

What does the fuel mix table report?

Essentially the fuel mix table is a series of percentages by supplier, representing the constituent parts of their energy generation.

These are generically listed as:

  • Coal
  • Gas
  • Nuclear
  • Renewable
  • Other

In addition the table also discloses:

  • The CO2 released in a supplier’s electricity generating processes


  • A measure of the high level radioactive waste produced during the supplier’s electricity generating processes

Of course not all suppliers generate their own energy and therefore find it necessary to source this information from the third party generators that they purchase their energy from in order to provide the fullest picture possible.


The latest 2013/14 Fuel Mix Disclosure table was published by DECC on 31st July 2014, this revealed that the national average was now:

Energy Source%


In contrast the 2012/13 fuel mix disclosure table, published on 1st August 2013 revealed that the national average was:

Energy Source%

CO2 emissions in g/kWh              469.3
Radioactive waste in g/kWh        0.00185


In contrast, the first recorded fuel mix disclosure table, for the disclosure period of 1st April 2007 to 31st March 2008 was:

Energy Source%

CO2 emissions in g/kWh              480.0
Radioactive waste in g/kWh         0.0014

The Fuel Mix history 2007-2014

Over this relatively short 6-year period we can see that renewable energy sources have trebled, whilst the contribution of gas has significantly reduced as increasing amounts of cheap imported coal has flooded the market and led it to becoming the dominant fuel source instead.

Nuclear energy has grown marginally, perhaps to its peak, if new build nuclear doesn’t come on tap shortly, while other sources such as oil have remained stable.

In positive news for the environment, CO2 emissions in the 5 years to 2013 have reduced to 469g/kWh from 480g/kWh, although High Level Radioactive Waste (created by the reprocessing of spent nuclear fuel) has increased to 0.00185g/kWh from 0.00140g/kWh.

How is Fuel Mix useful in determining your electricity supplier?

In simple terms, a business energy customer can compare the relative fuel mixes of each supplier to determine which supplier best suits their particular wants and needs.

For instance if you are a proponent of nuclear energy you could identify the energy suppliers with the greatest contribution of nuclear in their portfolio and contract with them accordingly.

Likewise you may as a business be anti-fossil fuel and therefore be looking to avoid those suppliers with a high concentration of coal or gas in their fuel mix.

You can even employ your environmental consciousness to tap into an energy supplier dominated by renewable energy without having to purchase a premium priced ‘green’ energy contract.

To understand your supplier’s fuel mix visit our dedicated supplier pages. If you already know who your preferred supplier is then simply call us and we’ll secure you a great deal at the right price with the right fuel mix for your business.

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