Decarbonisation Technology - February 2025 Issue

assume that all their biomass inputs end up in their facilities’ outputs, despite the fact that the input of renewable feedstocks will often have different reactivity than their fossil counterparts and will not necessarily produce the same quantity of outputs. By basing calculations solely on production inputs rather than outputs, these methods can systematically over-report the renewable share of fuels. Furthermore, ASTM-approved AMS Method B for carbon-14 analysis offers unparalleled precision compared to alternatives like Method C. Where ASTM D6866 Method B uses the AMS instrument to measure carbon-14, Method C uses liquid scintillation counting (LSC). In Method B, the AMS instrument directly measures the carbon-14 isotopes. However, in Method C, scintillation molecules indirectly absorb the beta molecules that release with the decay of carbon-14 and convert the energy into photons, which are measured proportionally to the amount of carbon-14 in the sample ( Baranyika, Piotrowski, Klusek, Michczynski, & Pawlyta, 2022 ). In this case, since Method B directly measures the carbon-14 isotopes while Method C measures them indirectly, Method B is significantly more precise. There are also limitations in the LSC technique due to the type of liquids that can be tested. While AMS is applicable to a larger range of products and is used to measure solid, liquid, or gaseous samples, clear or colourless liquids are the only sample types that can be measured accurately using the LSC method. From a regulatory standpoint, under the CFR, ASTM D6866 Method B (AMS) or Method C (LSC) can be used. If using carbon-14 testing, the CFR AMS method requires monthly testing. However, the LSC method requires that the analysis be performed weekly. In terms of sampling and shipping samples for analysis, it is advantageous to conduct only monthly tests rather than weekly ones as they reduce operational burdens and costs while having an accurate method to rely on, which underscores the benefits of ASTM D6866 Method B. Overall, compared to other test methods, the key advantage of carbon-14 analysis is that it is a standardised and direct measurement of any carbon-containing substance that produces highly accurate and precise values. In that

Carbon-14 analysis results % Fossil carbon vs Biogenic carbon

% Fossil carbon

% Biogenic carbon

Petrochemicals have fossil carbon (no Carbon-14)

Carbon-14 is present in living and recently expired materials

Products can be:

0% biogenic

100% biogenic

A combination 40% fossil carbon 60% biogenic carbon

Furthermore, British Columbia’s LCFS programme proposed an updated protocol in October 2023, adding ASTM D6866 testing for all co-processed fuels and co-products. Emissions reductions and corresponding credits are quantified based on the amount of co-processed low-CI fuels produced and their reduced lifecycle CI, using the biogenic content results obtained through ASTM D6866 testing ( Gov. of Canada, 2023 ). Technological precision: Comparing methodologies Carbon-14 analysis is a well-established method that has been in use by many industries for several decades. Under ASTM D6866 Method B, carbon-14 measurements performed by commercial third-party laboratories are robust with accurate and precise results regarding the percentage of biogenic content. Carbon-14 measurements under ASTM D6866 Method B represent a direct test method, whereas calculation-based approaches such as mass balance make claims based on material inputs in production ( ISCC, 2024 ). For example, carbon-14 testing can provide verifiable data indicating that 5%, for example, is derived from renewable fuel (biogenic content), while the remaining portion is from other interactions in the refinery. Calculation-based results lead producers to Analysis reveals the percentage of fossil vs biogenic carbon content Courtesy: Beta Analytic