Common Questions about ASTM D6866

1. Why use ASTM D6866?
2. Why not just use any radiocarbon dating laboratory?
3. Is it necessary to manually sort all materials before incineration?
4. How does ASTM D6866 account for variability in the feedstock?
5. "Percent biomass" specifically relates % renewable (or fossil) carbon to total carbon, not to total mass or molecular weight. Does the result mean that 60% of the carbon atoms in the waste were from biomass source or 60% of the mass of waste was from biomass or are these both the same thing?
6. The accuracy for the method is said to be +/- 3%. A further comment suggests that when used on flue gas the technique can be as accurate as +/-0.4%. Regulatory bodies will probably take the result and then deduct the accuracy from it and so it is important to know what accuracy we should use and have a reasoned argument for it. I would prefer to use 0.4% than 3% if possible!
7. How can I convert the result received into a percentage energy content?
8. I am located in Europe, where do I ship the results?

Why use ASTM D6866?

The global "green" initiative is to associate renewable biomass with either reduced greenhouse emissions (Kyoto protocols) or energy produced from renewable biomass (ROCs). Since CO₂ is a major atmospheric culprit (if not "the" atmospheric culprit) relating policy criteria directly to CO₂ via ASTM-D6866 is most appropriate. All Guidelines, Such as the Renewable Portfolio Standard as well as the Voluntary Reporting of Greenhouse Gases, allow you to remove biogenic CO₂ directly from the cap.

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Why not just use any radiocarbon dating laboratory?

A lot of radiocarbon labs pretty much do "their own thing" and have their own reporting formats. This was unacceptable for the US Dept. of Agricultures objective for defining renewable content based on radiocarbon dating techniques. ASTM D 6866 was formulated to ensure that all calculated results are the same.

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Is it necessary to manually sort all materials before incineration?

No. The good news about using the ASTM D6866 result is that you do not need to know the tonnage factor (i.e. the weighing and sorting of all the material). Whether you burned 1 tonne or 20 tonnes in a given example, the ASTM D 6866 result would still be, for example, 71% renewable content. Knowing the tonnage CO₂ produced and the D6866 result, one can calculate exactly how much "renewable" carbon contributed to the energy production. This is necessary in such instances as the UK Renewable Obligation Program (OFGEM Fuel Measurement and Sampling Guidelines).

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How does ASTM D6866 account for variability in the feedstock?

Given that the feed stock proportions will continually change, continuous collection of CO₂ (via a controlled flow meter on the exit of a CEMS or stack probe) will give the true running average for the utilized collection period (e.g. 1 week, 1 month).

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"Percent biomass" specifically relates % renewable (or fossil) carbon to total carbon, not to total mass or molecular weight. Does the result mean that 60% of the carbon atoms in the waste were from biomass source or 60% of the mass of waste was from biomass or are these both the same thing?

It's saying that 60% of the carbon "in" the combusted mass was from renewable sources. It does not say 60% "of" the combusted mass was renewable material. The difference being "60% of the carbon in the combusted mass was renewable" vs. "60% of the mass itself was renewable". This is good news since carbon is the major component to energy production.

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The accuracy for the method is said to be +/- 3%. A further comment suggests that when used on flue gas the technique can be as accurate as +/-0.4%. Regulatory bodies will probably take the result and then deduct the accuracy from it and so it is important to know what accuracy we should use and have a reasoned argument for it. I would prefer to use 0.4% than 3% if possible!

The actual precision component to your analysis was about 0.4 %. This relates only to how well we know the result for the analyzed gas. In other words, how well we can reproduce the measurement on the sample analyzed. It does not relate to factors outside of the measurement itself. For example, how a result may change with how long you collect the gas. The +/- 3% absolute value is an empirically determined value based on variability in about 500 manufactured products which included renewable biomass. The study showed, that measuring samples in triplicate, by different laboratories, at different times, using different lots, "real" precision was not better than about 2-3%. How this relates to incinerated materials is not exactly known, but 3% is reasonable. By "absolute", it is meant regardless of whether the result is 5% renewable content or 95% renewable content, +/- 3% is assigned to each.

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How can I convert the result received into a percentage energy content?

Please refer to the report commisioned by the UK Renewable Energy Association and Columbia University which goes into detail on calculating the energy content here.

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I am located in Europe, where do I ship the results?

We now have an office located London, England. For the convenience of all of our European customers shipments may be sent there directly. For details see Shipping.

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