Verify the Biomass Fraction of Biofuels with ASTM D6866 Biogenic-Content Testing

Biogenic testing determines the fraction of biogenic versus fossil carbon in a sample. (Image: Beta Analytic)

Verification of biogenic-carbon content in biofuel blends can be used to maintain compliance with regulations and provide access to tax incentives.

As alternatives to traditional fossil fuels, biofuels and renewable diesel are processed from renewable, biomass-derived sources including vegetable oils, animal fats and recycled cooking grease. Fuel-industry professionals interested in verifying the biomass content of their diesel blends can benefit from the easily understood, reliable results achieved via biogenic-content testing. Biogenic-content testing is based on ASTM D6866-22 and EN 16640 analytical standards and harnesses the accuracy of carbon-14 analysis to validate the biogenic-carbon content of biodiesel and other renewable fuels. This testing is applicable to samples in liquid form, such as diesel fuels, as well as solid and gaseous samples. Carbon-14 analysis measures the percentage of biogenic (or biomass-derived) carbon versus fossil-derived material in a biofuel blend. Testing results provide valuable data that can be applied to monitoring progress toward carbon neutrality and can also be used to comply with regulatory requirements and obtain tax benefits.

Biogenic content is the ratio of the biomass and fossil fractions of a fuel sample. (Image: Beta Analytic)

Carbon-14 Analysis Verifies Biogenic Content

The ASTM D6866-22 and EN 16640 analytical standards recognize biogenic content as material containing organic and inorganic carbon from renewable sources, or biomass, including plant, animal, agricultural and marine materials. Biomass-derived materials contain the radioactive isotope carbon-14, which can be measured to identify the fraction of biomass (biogenic content) in renewable fuels and other products made from biomass-derived materials and feedstocks. During the lifecycle of a plant or animal, carbon dioxide, which contains the carbon-14 isotope, is exchanged with the atmosphere via photosynthesis and the food chain. Carbon-14 concentrations in the atmosphere exist at known levels, maintaining balance in biomass and allowing it to be accurately measured. When a plant or animal dies, it stops exchanging carbon dioxide with the atmosphere. The carbon-14 in the remaining organic matter begins undergoing the process of radioactive decay. Carbon-14 analysis has a detection limit of approximately 43,500 years. Once the decay process is complete, a material will no longer contain carbon-14. For this reason, fossil fuels will not contain any carbon-14.

An accelerator mass spectrometer is used to perform carbon-14 analysis. (Photo: Beta Analytic)

Carbon-14 analysis is performed using an accelerator mass spectrometer (AMS) instrument. Results are clear and easy to understand, indicating the amount of biogenic content in a given sample representing the ratio of biomass-derived and fossil-derived material. The biomass fraction of the result is reported as a percentage of biogenic content. A sample that is formulated completely from biomass will result in 100 percent biogenic content while a traditional fossil fuel will have zero biogenic content. A mixture that is made in full or part of biomass-derived feedstocks such as soybean or palm oil can have its carbon-14 fraction accurately detected, making this method a highly valuable tool for measuring the biogenic content.

Biogenic Content Testing Applications

Biogenic content measurement is widely applicable to biodiesel, renewable diesel/hydrotreated vegetable oil (HVO), sustainable aviation fuel (SAF) and other biomass-based renewable energy sources like ethanol and renewable naphtha, as well as feedstocks such as used cooking oil, palm-oil mill effluent, cashew-nutshell oil, municipal solid waste and more.

Biogenic testing is recognized by renewable fuel industry professionals as a reliable and highly accurate third-party verification tool for measuring the biogenic content of their biodiesel and biofuel blends. Carbon-14 analysis is widely used, with applications extending to refineries for the determination of biofuel-blend ratios originating from bio-oil as an alternative to petroleum feedstocks. Several key benefits of biogenic-content testing for the fuels market exist. Verification of biogenic-carbon content in biofuel blends can be used to maintain compliance with regulations and provide access to tax incentives. Additionally, data gained from testing can be used to monitor progress toward decarbonization and reaching net-zero goals as well as offering research and development teams a tool for measuring biogenic-content optimization.

When it comes to compliance, several regulatory programs recommend or require ASTM D6866 biogenic-content testing. The data obtained via carbon-14 analysis can be used to ensure renewable fuel manufacturers comply with current regulations to qualify for tax credits or carbon credits for carbon-intensity reduction. North American programs include the U.S. Renewable Fuel Standard, California’s Low Carbon Fuel Standard, Canada’s Clean Fuel Regulations, and Oregon’s Clean Fuels Program. ASTM D6866 testing is also applicable to a number of European standards including the Roundtable on Sustainable Biomaterials’ standard for advanced fuels, the EU’s Renewable Energy Directive and Emissions Trading System, and the Netherlands’ HVO regulation.

In conclusion, the renewable carbon sources from biomass used to develop biobased diesel fuel make it an ideal candidate for ASTM D6866 carbon-14 testing. Biogenic content is measured as a fraction of biomass and fossil-derived material. This is an accurate and easily understood method for validating biofuel blends. Results offer additional benefits for research and development as well as for companies seeking to reduce their carbon intensity and comply with current regulations.