Beta Analytic representative Mauricio Larenas talked about ASTM D6866 and its application to the cement and lime industries during the 3rd Global Fuels Conference for Cement and Lime held in Toronto, Canada, on June 15-16, 2009.
The conference focused on alternative fuel use in cement and lime plants. Samples of alternative fuels currently in use are municipal solid waste (MSW), biogas, used oil, non-recyclable plastics, and tires.
Mr. Larenas described how radiocarbon dating, or the analysis of carbon 12 and carbon 14 ratios, can determine the biogenic fraction of alternative fuels. He also highlighted the advantages of using ASTM D6866, the industrial application of radiocarbon dating. Industries using heterogeneous fuels will have less hassle and more accurate results if they have their gas emissions tested for biogenic fraction rather than the solid heterogeneous fuels due to sampling issues.
Mr. Larenas was commended on his presentation.
Sponsored by the Cement Association of Canada, the conference was held at the Sheraton Centre Toronto and was attended by 140 delegates from 23 countries.
Quantification of Carbon-Neutral Greenhouse Gas Emissions Using ASTM D6866
To mitigate global climate change, governments across the globe are now promoting the use of renewable sources of energy and encouraging industries to cut back on the use of fossil fuels. They are also setting up mandatory reporting protocols for greenhouse gas emissions (GHG).
To incentivize companies, many countries are now setting up a cap-and-trade scheme for GHG such as the one currently in effect in Europe. Through this scheme, companies in various industries can obtain carbon credits if they emit less GHG than their limits. These carbon credits have a monetary value and can be traded in markets.
In the U.S., major industries identified as heavy emitters of GHG will be obligated to report their GHG inventory by the U.S. Environmental Protection beginning next year. Companies need to characterize their GHG emissions into fossil-based and renewable carbon. The portion of their GHG emissions that came from biomass is carbon neutral and, therefore, can be deducted from their GHG inventories.
Carbon dioxide emitted from the combustion of biomass is said to be carbon neutral because it does not leave a carbon footprint. Also called biogenic CO2, this carbon dioxide is easily removed from the biosphere by plants.
ASTM D6866 is the most accurate analytical method available today that can easily quantify the biomass percentage in gases. This standard created by the American Society for Testing and Materials, at the request of the U.S. Department of Agriculture, encompasses the test methods for determining the biobased content of solid, liquid, or gaseous samples using radiocarbon analysis.
Radiocarbon dating can easily distinguish fossil-based inputs from biomass through any given sample’s carbon 14 content. This weakly radioactive carbon isotope is ubiquitous in all living things but gradually decays after an organism’s death such that none is left after 50,000 years. Fossil-derived materials no longer have carbon 14 while biomass-derived ones still do.
ASTM D6866 is a well-validated method that has found its way in many GHG reporting protocols. This standard has been incorporated in the mandatory reporting requirements of California’s AB32, Western Climate Initiative, and The Climate Registry.
The ASTM D6866 is not only applicable for renewable carbon testing, but it has also found an application for quantifying the biomass content of bioplastics and biofuels. Its European equivalent, the CEN/TS 15747, is used to monitor refuse-derived fuels for the European Commission’s Emission Trading Scheme. The EU-ETS also allows the use of ASTM D6866 for monitoring various types of heterogeneous fuels.
The Australian government has recommended the use of ASTM D6866 for testing the biobased content of blended fuels. The Renewable Obligation Certificate program in the United Kingdom is also considering this method for monitoring biomass energy production.
Industries that benefit from the use of ASTM D6866 to quantify the biogenic portions of their CO2 emissions include the waste-to-energy (energy-from-waste) industry, electricity-generating facilities, coal co-firing plants, as well as steel and cement manufacturers.
ASTM D6866 METHOD
The application of ASTM D6866 to derive “biomass CO2 content” for carbon dioxide effluents is built upon the same concepts as those used by the USDA to derive the biobased content of manufactured products containing biomass. It is done by comparing a relative amount of radiocarbon (carbon 14) in an unknown sample to that of a modern reference standard. The ratio in contemporary biomass is 100%, and the ratio in fossil materials is zero. Carbon dioxide derived from combustion of a mixture of present-day biomass and fossil carbon will yield an ASTM D6866 result that directly correlates to the amount of biomass carbon combusted and carbon-neutral CO2 generated.
Radiocarbon Dating Methods
ASTM Method A uses Liquid Scintillation Counting (LSC) radiocarbon techniques to analyze CO2 cocktails after collecting the CO2 in a suitable absorbing solution. This method has a maximum total error of 15% associated with sample preparation and actual counting.
ASTM Method B uses Accelerator Mass Spectrometry (AMS) and Isotope Ratio Mass Spectrometry (IRMS) techniques. Sample preparation is more complex than Method A and uses more sophisticated instruments. Possible uncertainty is 1%-2% for AMS and 0.1% to 0.5 % for IRMS.
Method C uses LSC techniques to analyze sample carbon that has been converted to benzene. This test method has a maximum total error of ±3% (absolute).
Real precision for readily combustible and homogenous materials (e.g. gasoline), especially samples received as CO2 (e.g. flue gases or CEMS exhaust) can be as low as ±0.5-2%.
The modern reference standard is a National Institute of Standards and Technology (NIST) standard with a defined radiocarbon content of 100% contemporary carbon for the year AD 1950. This year was chosen since it represented a time prior to thermonuclear weapons testing, which introduced large amounts of excess radiocarbon into the atmosphere with each explosion (termed “bomb carbon”). This was a logical point in time to use as a reference since this excess bomb carbon would change with increased or decreased weapons testing.
A fixed correction for bomb carbon is applied per the ASTM D6866 requirements, applying specifically to carbon removed from the atmospheric CO2 reservoir since about 1996. Carbon removed prior to about 1996 will contain elevated radiocarbon signatures not directly applicable to the ASTM D6866 correction. Typical areas to which the correction may not apply are landfills that are more than 5-10 years old and to trees which began to grow more than 20 years ago.
ASTM D6866 Results and Discussion
Carbon dioxide effluent derived from combustion of 100% present-day biomass will yield results of 100% renewable content while those derived from the combustion of 100% fossil fuel will yield results of 0% renewable content.
Carbon dioxide produced from mixed fuels (biomass plus fossil fuel) will yield a percentage result in direct proportion to the biomass carbon vs. fossil carbon consumed in the combustion. The final result is referred to as the Mean Biomass Carbon Dioxide Content and assumes that:
1. all the carbon in the carbon dioxide was derived from either present-day living or fossil sources; and
2. the desired result is the amount of biomass component “present” in the material, not the amount of biomass material “used” in the manufacturing process.
ASTM D6866 results relate directly to the percentage carbon-neutral CO2 in an incineration effluent. A value of 73% renewable content measured on CO2 effluent would indicate that 73% of the exhausted CO2 was from biomass and 27% from fossil fuel. It does not represent the weight of biomass combusted or the weight of fossil fuel combusted. This is advantageous since the weight of the fuels only indirectly relate to the up-take of carbon dioxide from the atmosphere. The respiration uptake compound was carbon dioxide, and the combustion effluent was carbon dioxide. The ASTM D6866 result directly and specifically relates to the amount of carbon-neutral CO2 consumed and expelled.
ASTM D6866’s simple, visual reports are easy to understand and instinctively obvious.
It must be noted that ASTM D6866 results are reported as “percent biomass” or the percentage of renewable carbon relative to total carbon and not to total mass of the sample or molecular weight.
MANDATORY REPORTING PROTOCOLS
Many reporting rules now incorporate ASTM D6866 for measuring the biogenic fractions of carbon dioxide emissions.
U.S. Environmental Protection Agency
The EPA’s proposed mandatory greenhouse gas reporting rule excludes from calculations carbon dioxide emissions from the combustion of biogenic fuels. It recommends the use of ASTM D6866:
“For a unit that combusts MSW, the owner or operator shall use, for each quarter, ASTM Methods D6866 and D7459 … to determine the relative proportions of biogenic and non-biogenic CO2 emissions when MSW is combusted.”
“The owner or operator shall separate total CO2 emissions from MSW combustion into biogenic emissions and non-biogenic emissions, using the average proportion of biogenic emissions of all samples analyzed during the reporting year.”
California Air Resources Board
California’s AB32 recommends that these companies use ASTM D6866 to determine CO2 emissions from the combustion of biomass, municipal solid waste, or waste-derived fuels with biomass, or co-firing of fuels:
* operators of general stationary combustion facilities
* operators of electric-generating facilities, electricity retail providers, and marketers who import or export electric power across California’s borders
* cement plant operators
Western Climate Initiative
The final draft of the Western Climate Initiative’s essential requirements of mandatory reporting, released in May 2009, requires:
1. “The owner or operator that combusts fuels or fuel mixtures for which the biomass fuel fraction is unknown or cannot be documented (for example, municipal solid waste or tire-derived fuels) shall determine the biomass fuel portion of CO2 emissions using ASTM D6866…”
2. An operator who uses CEMS data to report CO2 emissions from a facility that co-fires fossil fuels with biomass fuels or waste-derived fuels that are partly biomass fuels shall determine the portion of total CO2 emissions separately assigned to the fossil fuel and the biomass fuels using ASTM D6866.
3. Operators who combust waste-derived fuels that are not pure biomass fuels shall determine the biomass fuel portion of CO2 emissions using ASTM D6866.
The Climate Registry
The Climate Registry, which establishes consistent standards throughout North America for businesses and governments to calculate, verify and publicly report their carbon footprints, also mentioned ASTM D6866 as one of the methods to use when calculating emissions from waste fuels and biomass. [TCR General Reporting Protocol Version 1.1 May 2008]
European Union Emission Trading System
The EU-ETS FAQ released in 2007 identifies ASTM D6866 as standard available for the determination of biomass fractions of fuels or materials.
ETS (Directive 2003/87/EC): Answers to Frequently Asked Questions On Greenhouse Gas Emissions Monitoring and Reporting under the EU ETS
Q29. Are international or national standards available for the determination of biomass fractions of fuels or materials?
Answer: ASTM D 6866 – 05: Standard Test Methods for Determining the Biobased Content of Natural Range Materials Using Radiocarbon and Isotope Ratio Mass Spectrometry Analysis.
UK Environment Agency
Howard Leberman, the Industry Regulation Policy Advisor, states:
“We accept that the natural rubber content of tyres may be considered as biomass under EU ETS and is in accordance with the definition set out in Section 2(4)(f) of the Commission’s monitoring and reporting guidance.”
“We accept your proposed methodology of carbon isotope analysis to determine the non-fossilised carbon content of tyres.”
“This decision has been endorsed by the UK regulators and Defra at the UK regulators telecom on the 17th April 2008 and will apply from the 1st January 2008.”
Australia’s National Greenhouse and Energy Reporting (Measurement) Technical Guidelines 2008 recommends ASTM D6866 as method for blended solid and liquid fuels.
ASTM D6866 is an accurate and precise monitoring and verification tool for carbon credit and carbon offsetting strategies because it easily distinguishes carbon from biomass from carbon that comes from fossil fuels. ASTM D6866 can measure renewable content of solid, liquid, or gaseous samples, and this flexibility makes it applicable to many industries.
This entry was posted on Wednesday, June 24th, 2009 and is filed under Beta Analytic Updates .