Thierry Sam Tamers, Beta Analytic director, recommends the use of ASTM D6866 to measure the biomass fraction of municipal solid waste in a public comment submitted to the U.S. EPA in connection to the revised Renewable Fuel Standard Program.
Pertinent excerpts of the public comment:
The EPA solicits comments whether the biomass fraction of municipal solid waste should be allowed as a feedstock for biofuels. We believe that it should particularly since the ASTM D6866 test can accurately determine the biomass fraction of the resultant fuel. It must be noted that the ASTM D6866 method is already adopted in the current EPA’s greenhouse gas reporting rule under the Tier 4 sampling protocol for municipal solid waste (pages 16636 to 16639), specifically for the measurement of the biogenic CO2 fraction.
As a reminder, the ASTM D6866 method is a standardized version for industrial use of radiocarbon dating, an analytical technique that was developed in the 1950s. The same principles of dating (i.e. analysis of the carbon-14 atom) can also be used to measure the biomass component of fuels and other materials. Biomass contains a well-characterized amount of carbon-14 that is easily distinguished from other materials such as fossil fuels that do not contain any carbon-14. Since the amount of carbon-14 in biomass is well known, a percentage of biogenic carbon can be calculated easily from the overall carbon atoms in the sample.
The ASTM D6866 method is the only analytical method that can determine the biomass carbon fraction of fuels that are chemically identical. For example, synthetic ethanol made from fossil fuels is chemically indistinguishable from bioethanol made from a biomass feedstock. ASTM D6866 is the only method that can determine precisely the percentage of biogenic carbon in ethanol samples. The same holds true for methanol from biomass and fossil fuel sources. In a similar light, the ASTM D6866 method can help resolve biomass fraction ambiguities in complex fuel mixes such as Hydrogenation-Derived Renewable Diesel (HDRD).
Although the ASTM D6866 method cannot determine the different renewable biomass feedstock percentages, it can determine with excellent accuracy and precision the biomass carbon fraction of fuels. Recent blending fuel incidents in Nebraska and the Reddy paper cited below demonstrate the need for an analytical test such ASTM D6866 to verify the exact blend percentages. As such, the ASTM D6866 test can be used to verify overall blending percentages, particularly imported biofuels where regulatory oversight might not be a rigorous as in the United States.
To further add weight to our argument that ASTM D6866 method should be used to determine the biomass fraction of biofuels and biomass/fossil fuel blends, we are including three links of recently published research notes on the carbon-14 technique for these types of fuels. As can be seen from these research notes, the carbon-14 method works very well in determining the biomass fraction of fuels.
Dijs, Ivo J; van der Windt, Eric; Kaihola, Lauri; van der Borg, Klaas. QUANTITATIVE DETERMINATION BY 14C ANALYSIS OF THE BIOLOGICAL COMPONENT IN FUELS. RADIOCARBON, Vol 48, Nr 3, 2006, p 315-323.
Reddy, C.M., J.A. DeMello, C.A. Carmichael, E.E. Peacock, L. Xu, and J.S. Arey, Determination of Biodiesel Blending Percentages Using Natural Abundance Radiocarbon Analysis: Testing the Accuracy of Retail Biodiesel Blends, Environmental Science & Technology 2008 42 (7), 2476-2482.
Lastly, it must be mentioned that ASTM D6866 is an accepted method for measuring the biomass fraction of fuels in the Australian, European Union, and other regional greenhouse gas protocols, such California’s AB 32 and the Western Climate Initiative. This widely accepted method is also being considered as a biomass carbon verification test for the Renewable Transportation Fuels Obligation in the United Kingdom.
The Renewable Fuel Standard program aims to increase the volume of renewable fuel required to be blended into gasoline from 9 billion gallons in 2008 to 36 billion gallons by 2022. The new U.S. RFS program regulations are being developed in collaboration with refiners, renewable fuel producers, and many other stakeholders.