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Email: richard.bellingham@ofgem.gov.uk
Date: 8 July 2011

Dear Colleagues,
Determination of biomass energy content of waste feedstock by post combustion
analysis of flue gases: Carbon-14 technique proposal
The Renewables Obligation (RO) Orders set out that the Authority must issue Renewable
Obligation Certificates (ROCs) on electricity generated from renewable source where allnecessary eligibility criteria have been met. In addition, the RO requires that ROCs can only
be issued on the basis of ‘accurate and reliable’ information having been provided to us.
When considering issuance of ROCs on fuelled generating stations, we work with generators
to agree a Fuel Measurement and Sampling (FMS) procedure that will allow them todetermine the renewable energy fraction of their feedstock as accurately as possible.
When a new FMS procedure is proposed to Ofgem we must be sure it is capable ofproducing data of adequate accuracy for the issuance of ROCs. The vast majority ofgenerating stations using waste as a feedstock currently sample the waste to determine its
renewable content. We acknowledge that these sampling methods can be time consuming
and expensive, with the heterogeneous nature of waste acting as a barrier to accurate
figures.
A new FMS proposal has been put forward, concerning the use of a Carbon-14 (14C)
technique that analyses flue gases. It has been proposed that this, post-combustion
technique could be used to accurately determine the renewable energy content of a waste
feedstock burnt in a generating station.
When considering this proposal, we commissioned an independent report to review thescience behind the 14C technique and to comment on whether it is as accurate as thesampling procedures currently used. Members of the Renewable Energy Association (REA)
also commissioned an independent report to review the 14C technique and have shared thecontent of this report with us.
Both independent reports concluded that the 14C technique is based on mature and wellunderstood technology. The reports also concluded that results from this technique would
be at least as accurate as the existing sampling methods used.
We are therefore prepared to consider FMS procedures that propose to use the 14Ctechnique. As always, the FMS proposals will be considered on a case by case basis, taking
into account the different feedstock used and the nature of each generating station. We are
The Office of Gas and Electricity Markets
9 Millbank London SW1P 3GE Tel 020 7901 7000 Fax 020 7901 7066 www.ofgem.gov.uk

currently preparing a dedicated FMS questionnaire to be completed by stations proposing touse the 14C technique. This will be published on our website in due course.
In particular generating stations will be required to submit details of:
The procedure for sampling flue gases
The technique for determining the 14C to 12C ratio in samples of flue gas
The carbon ratio to energy calculations
We would like to emphasise that generators are under no obligation to use the 14Ctechnique. We will continue to consider proposals using the existing methods used byindustry. Despite this, we see the potential for the 14C technique as a positive step in termsof recognising a new method for generators to consider when setting about making anapplication for accreditation to us.
Yours sincerely,Richard Bellingham
Manager Renewables: Biomass, Waste and Co-firing

2 of 2The Office of Gas and Electricity Markets
9 Millbank London SW1P 3GE Tel 020 7901 7000 Fax 020 7901 7066 www.ofgem.gov.uk