Sustainable energy and the fuel mix
This article explains how to assess how much of the electricity consumed in the UK is derived from sustainable green sources.
How do electricity consumers know which source produces their power; for instance, what comes from a sustainable green source (renewables such as wind power or hydro-electric) and what comes from fossil fuels (mainly natural gas and coal)? This information is provided by their electricity supplier in the Fuel Mix Disclosure (FMD) statement.
All licensed electricity suppliers in the UK are required by law to disclose to potential and existing customers the mix of fuels used in generating the electric power supplied. This obligation was introduced by The Electricity (Fuel Mix Disclosure) Regulation 2005 (S.I. 2005 No. 391).
The information is typically given in the form of a table, with the following disclosure being an example for 2020/21 published by one of the major UK electricity suppliers in their customer literature:
SourceFuel Mix
Coal 3%
Gas 38%
Nuclear16%
Renewables 40%
Other fuel 4%
Who monitors the integrity of this disclosure?
OFGEM (The Office of Gas and Electricity Markets), the UK’s independent energy regulator, monitor the integrity of the disclosures.
The FMD statement requires evidence to be given by the electricity supplier to OFGEM of what they report is the renewables proportion of their total fuel mix. Proof of this proportion is satisfied by having a document called, in the UK, the Renewable Energy Guarantee of Origin (REGO) certificate. The REGO scheme was established in 2003 as a means of tracking renewable electricity generation across the European Union.
The REGOs are issued by OFGEM on receipt of generating data from a REGO accredited generating station (which, for example, can be a windfarm site or a hydro-electric plant).
The REGO scheme is designed to provide transparency to consumers about the proportion of electricity that suppliers obtain from renewable generation. It is important that consumers, if they are keen to choose renewable energy, can place their confidence in the information published in the Fuel Mix Disclosure statement when choosing an electricity supplier.
Who can apply for accreditation?
Electricity generating entities of any size in the UK who produce either all or at least a proportion of their total power output from renewable sources can apply to OGEM for inclusion in the REGO scheme and become listed as a ‘licensed generator’.
Licensed generators must provide generation data each month to OFGEM via a Register to receive REGO certificates. Once these have been issued by OFGEM, the generator will then hold the certificates on the Register.
Annual FMD and REGOs
The annual generation disclosure period for the FMD statements runs from 1 April to the following 31 March. OFGEM carries out an annual recapitulation exercise for this period and requires licensed electricity suppliers to have evidence to support their renewables figure by the deadline date of 1 July. Suppliers are responsible for contacting the relevant generators, from whom they have purchase bulk electric power, to ensure that the REGOs are transferred across to them by the July deadline.
OFGEM emphasises that it is critical that consumers can place reliance on the fuel mix disclosure information given by electricity suppliers and this information complies fully with the requirements in the regulations This places a onus on suppliers to ensure an accurate FMD statement is readily available to consumers, and that it is easy to understand.
Checking the authenticity of the Fuel Mix Disclosure
OFGEM undertake reviews of suppliers FMD statements to ensure compliance with the regulations on the disclosure of the proportion of renewable electricity supplied to customers. This includes checks that suppliers hold sufficient REGO certificates to support the declaration given by them of the proportion of electricity from renewable sources. A summary of the findings from these reviews is published on the OFGEM website.