On 14C-based methods for measuring the biogenic carbon fraction in fuels and flue gases

Several international regulations distinguish between carbon from biomass and carbon from fossil raw materials for different materials and CO2 emissions. Due to these regulations it can be financially beneficial for companies to claim for instance their products to originate from 100% biomass, that a diesel product contains 10% bio-diesel, or that the CO2 emissions of an incineration plant are not 100% fossil but only 40%. How can a company measure this if the origin or mixing of ingredients used for the product or in the combusted fuels is not known? And how can authorities verify reported biogenic and fossil CO2 emissions? Using methods in which carbon-14 measurements are used are the answer to these questions, as these methods specifically distinguish between biogenic and fossil carbon fractions. Fossil carbon does not contain radioactive carbon-14 anymore due to the very long period of decay, while biomass carbon does. The less carbon-14 is measured in a sample material the larger the fraction of fossil carbon. In this PhD research the application of carbon-14 measurements for the measurement of the biogenic carbon fraction has been investigated for flue gas CO2, mixes of biogas and natural gas, and different gases from a specific synthetic natural gas production process. All these carbon-14 based applications have proven to be very suitable, especially if the applied methods were optimized for the specific sample types. The application of carbon-14 based methods in practice, especially by companies and usually based on standards, is discussed as well.