Where SRF or MSW is combined with biomass in a boiler within a CHP scheme, the type of ROCs issued depends on the biomass content of the overall fuel mix, i.e. if it is less than 90% biomass it will all be treated as waste and will receive EfW with CHP ROCs (1 ROC / MWh) on the biomass energy content and if it is equal to or greater than 90% biomass it will all be treated as biomass and will receive dedicated biomass with CHP ROCs (2 ROCs/ MWh) on the biomass energy content.
Consideration has been given to extending the application of neutrality to SRF beyond use alongside biomass in a fossil fuel power station, to use in other types of generating station. There is concern, however, that such an extension could simply encourage the artificial separation and then recombination of the same waste with no added benefit to society. Defra and DECC will monitor how the SRF market develops to see what changes to this stance might be appropriate in light of the development of cost effective, on-site measurement techniques.
These principles apply to the co-firing of biomass, co-firing of energy crops and co-firing of biomass or energy crops with CHP. For example, if a dedicated CHP plant is fuelled by a mixture of wood and SRF, so that less than 90% of the overall fuel mix derived from plant or animal matter, it would receive 1 ROC/MWh for all the electricity derived from the biomass element of that fuel. However, if the same plant burned these two fuels in separate boilers, the plant would receive 1 ROC/MWh for the electricity from the wood but no ROCs for the energy derived from SRF (as a co-firing with CHP plant with neutrality to SRF).
The ROC eligibility attached to a number of fuel and technology options is set out Chapter 2 of Ofgem's Renewables Obligation Guidance on Fuel Measurement and Sampling (reference 14 above).