Beta submitted a comment on the question posed in Section 3.39 of the Renewables Obligation: DRAFT Fuel Measurement and Sampling Guidance document published in December 2008.
Thierry Sam Tamers, Beta Director, wrote:
Although the potential cost of auditing a generator off-site should best be addressed by verifiers, we would like to mention that off-site measurement of flue gases is not only feasible but also economical. This is particularly true for measurement of the biomass fraction of flue gases and, consequently, the measurement of the biomass fraction of energy produced. In 2007, OFGEM commissioned a study with the Renewable Energy Association that demonstrated that it is feasible to measure off-site the biomass energy fraction with radiocarbon dating.
Standardized off-site measurement of the biogenic carbon fraction of fuels by radiocarbon dating is now available with two standard methods: ASTM D6866 in the US and CEN/TS 15747:2008 in Europe. These standard methods can determine the biogenic fraction of any gas, liquid, or solid sample. In the United States, a new method called ASTM D7459-08 was also developed to standardize the collection of off-site flue gas for biogenic carbon emissions.
Analyzing flue gas samples off-site is particularly advantageous because the resultant gas from the combustion of multiple fuel samples can be amalgamated into one gas bag. Consequently, a true representation of the combusted fuel can be measured over the combustion history of several hours to several months with only one gas bag. The analysis by radiocarbon dating of one gas sample during a continuous period can be more economical and, more importantly, more representative when compared to methods that must analyze the solid fuel sample. Several studies have also demonstrated that radiocarbon dating is more accurate in determining the biomass fraction of fuels compared to other analytical methods.
CEN/TS 15747:2008 has been superseded by EN 15440.
Last updated December 2014