Measuring Biogenic Carbon Content through ASTM D6866

  • ASTM D6866 measures biogenic carbon content of solid or liquid fuels and their combustion emissions.
  • The test is an accurate monitoring and verification tool for carbon credit and carbon offsetting strategies.
  • Beta Analytic provides ASTM D6866 testing to various companies as they comply with regulations or take advantage of certain initiatives.

ASTM D6866 Background

ASTM D6866 refers to the standard test methods for determining the biogenic carbon content of solid, liquid, and gaseous samples using radiocarbon analysis. Methods include Liquid Scintillation Counting (LSC), Accelerator Mass Spectrometry (AMS), and Isotope Ratio Mass Spectrometry (IRMS) techniques.

For solid recovered fuels and CO2, ASTM D6866 measures the biogenic carbon content – the amount of biomass-derived carbon in the material as compared to its total carbon content.

ASTM D6866 was first adopted in 2004. Revisions have been made since then. Some protocols or official reports may refer to this standard as ASTM D6866-04, ASTM D6866-04a, ASTM D6866-05, ASTM D6866-06, ASTM D6866-06a, ASTM D6866-10, ASTM D6866-11,  ASTM D6866-12, ASTM D6866-16, ASTM D6866-18, ASTM D6866-20, ASTM D6866-21 or ASTM D6866-22. The current active version of the standard is ASTM D6866-24 effective February 2024.

The ASTM D6866 working standard was completed in 2004 and is now cited in Federal Law (7 CFR part 2902). It is used for designating manufactured items for inclusion in the federal government’s preferred procurement list. This standard was written at the request of the USDA to satisfy legislation requiring federal agencies to prefer procurement of products with the greatest amount of renewable biomass (vs. plastic or other fossil components) in their products (per the 2002 Farm Bill). A standardized method was needed to verify manufacturers’ claims of biobased content. Radiocarbon dating was directly applicable but was an unregulated industry. The USDA needed standardization of the techniques and reporting for the purposes of inclusion in regulatory policy.

Official ASTM D6866 page

Principles Behind ASTM D6866

Natural levels of radiocarbon in organic materials are used to derive an ASTM D6866 result. No “radioactivity” as defined by regulatory bodies is utilized in the analysis. Carbon 14 or radiocarbon—a weakly radioactive, naturally occurring element in all living things—is present in a defined level. Contemporary biomass has 100% radiocarbon and is absent (0%) in fossil fuels. ASTM D6866 uses this difference to determine the amount of biomass CO2 vs. fossil CO2. The method was used to quantify biomass CO2 present in the bulk CO2 (or methane) effluent derived from combustion and bacteriological sources.1

Simple and Accurate Method

A true running average of carbon-neutral CO2 emission vs fossil CO22 emission is obtained by connecting a continuous gas flow controller to the exhaust port of existing continuous emission monitoring systems (CEMS). As the feedstock of a co-firing plant varies over the course of a month, all variations pertaining to biomass carbon and fossil carbon are accounted for in a single result (representing the average of both components represented in the CO2 effluent).

Cutting, sorting, and weighing of mixed fuel is not needed for determination of greenhouse gas vs. carbon-neutral gas emissions. This “back-end” approach provides a result indicating “what was done” rather than complicated estimates based on “what we think we did” derived from the front-end approach.

The Institute of Clean Air Companies (ICAC) has examined and recognized the role that ASTM D6866 plays in greenhouse gas testing (see details here).

Since a single percentage value is universally applicable to all measurements, both regulatory and financial bodies are provided with a single reference for use in comparative monitoring and trading.

Studies are under way to test the applicability of the result to gross calorific value (energy/heat). Pilot studies are in the planning stages with the Renewable Energy Association in the UK and the Electric Power Research Institute (EPRI) in the US.

Significance of ASTM D6866

Companies can benefit from their ASTM D6866 lab results in two ways. Depending on the prevailing regulations in their home countries, they can use the result to support their reduced greenhouse gas inventory. For those companies in countries with a cap-and-trade program in place, the ASTM D6866 results can help them obtain more carbon credits.

For example, a company that owns a co-firing plant burning 50% straw and 50% coal can reduce its GHG inventory by 50%. Carbon dioxide emissions from burning straw are carbon-neutral and deductible from a company’s GHG inventory. The reduced emission level helps the company comply with regulations and obtain carbon credits if there is a cap-and-trade system established within its home country.

ASTM D6866 is now used to verify the biogenic (biomass) fraction of heterogeneous fuels and their CO2 emissions as required in greenhouse gas protocols. The method has been incorporated into reporting protocols in the US, Australia, and Europe. A variant of ASTM D6866 is used to monitor refuse-derived fuels for the European Union’s Emission Trading Scheme.

The European Union also allows the use of ASTM D6866 for monitoring other types of heterogeneous fuels. The Australian government has incorporated similar recommendations for the use of ASTM D6866 for blended fuels. The Renewable Obligation Certificate program in the United Kingdom is also considering this method for monitoring biomass energy production. The method has also been incorporated in a United Nations Clean Development Mechanism methodology concerning solid waste management.

Beta Analytic Provides ASTM D6866 Testing

Located in Miami, Florida, ISO/IEC 17025:2017-accredited Beta Analytic is committed to help clients meet regulation requirements by providing high-quality ASTM D6866 services. The company has an office in London, UK, for the convenience of clients throughout Europe. Clients in Japan and China are also better served by Beta Analytic facilities and business development representatives in their respective countries.


1. Mook, W. G. The Effect of Fossil Fuel and Biogenic CO, on the 13C and 14C Content of Atmospheric Carbon Dioxide . RADIOCARBON, VOL 22, No. 2, 1980, P 392-397.

2. SrdoZ, Dugan; Ahel, Nada Marijan; Giger, Walter; Schaffner, Christian; Bronid, Ines Krajcar; Petricioli, Don at; Pezdie, Jofe; Marcenko, Elena; Plenkovie-Moraj, Andjelka. Anthropogenic Influence on the 14C Activity and Other Constituents of Recent Lake Sediments: A Case Study . RADIOCARBON, VOL. 34, No. 3, 1992, P. 585-592.

Page last updated: July 2024