# My lab report gives carbon and calorific value for my petcoke or coal. How do I tell whether my own carbon dioxide factor is consistent with the Intergovernmental Panel on Climate Change default?

Canonical: https://senseible.earth/answers/is-my-lab-co2-factor-within-ipcc-default-range

Turn the lab's carbon percentage and net calorific value (NCV) into kilograms (kg) of carbon dioxide (CO2) per terajoule (TJ), then compare it with the Intergovernmental Panel on Climate Change (IPCC) 95% range for that fuel. IPCC says a factor inside the range could be regarded as consistent with the default. Outside it, check basis and fuel type first.

## The test IPCC gives

- IPCC 2006, Volume 2, Chapter 1, section 1.5.3 says: Whenever a national specific emission factor falls within the 95 percent confidence interval, it could be regarded as consistent with the default value.
- It adds that one would expect the uncertainty range of country-specific values for application in that country to be smaller than the default range.
- Both sentences are written for national inventories. Using them on one plant's lab factor is my reading, not something IPCC states.

## Steps

1. Take the carbon fraction from the lab report on the same basis as the fuel you weigh, normally as received.
2. kg CO2 per kg of fuel = carbon fraction x 44/12.
3. Divide by the NCV in megajoules (MJ) per kilogram, on the same basis. The result is kg CO2 per MJ. Multiply by 1,000,000 for kg per TJ.
4. Compare with the lower and upper limits in Table 1.4 for the right fuel line. Inside: you can say it could be regarded as consistent with the IPCC default, which is IPCC's wording. Outside: do not discard the lab figure. Look for the cause first.

## If it falls outside the range

- Basis mismatch: carbon on a dry basis with NCV as received, or the reverse. Dry-basis carbon is higher than as-received carbon, so that mix overstates the factor, and the reverse understates it.
- Gross calorific value (GCV) used where the factor needs net. GCV is higher than NCV, so dividing by it gives a lower factor per unit of energy than the net basis. Convert first.
- Wrong fuel line: a low-grade coal can sit better against the sub-bituminous or lignite range than against other bituminous. The coal-lines answer on this site lists IPCC's thresholds.
- A real difference in the fuel. That is allowed. Keep the lab report and say so in the method note.

## Two lab reports checked against Table 1.4, example values

- Petcoke: carbon 87.0% as received, NCV 33.0 MJ per kg (example values)
- 87.0% x 44/12 = 0.87 x 3.6667 = 3.19 kg CO2 per kg
- 3.19 / 33.0 = 0.09667 kg per MJ = 96,667 kg per TJ
- IPCC petroleum coke: 97,500 with a range of 82,900 to 115,000. 96,667 is inside, so consistent
- Coal: carbon 45.0% as received, NCV 16.0 MJ per kg (example values)
- 0.45 x 3.6667 = 1.65 kg CO2 per kg; 1.65 / 16.0 = 0.103125 kg per MJ = 103,125 kg per TJ
- Other bituminous coal range is 89,500 to 99,700 and sub-bituminous is 92,800 to 100,000. 103,125 is 3.4% above the first upper limit and above the second. The lignite range, 90,900 to 115,000, contains it
- Next step: check which coal line fits, and whether carbon and NCV share a moisture basis. Do not simply overwrite the lab figure

These lab values are examples, not typical results for any grade.

## What Senseible does here

Senseible reads fuel invoices and electricity bills into monthly records. The lab-factor comparison is arithmetic you do on the lab report. Keep the report beside the records so a buyer can follow it.

- [How far off can a default fuel factor be?](https://senseible.earth/answers/ipcc-default-fuel-factor-95-percent-range-by-fuel)
- [Using coal carbon content from a lab](https://senseible.earth/answers/coal-ultimate-analysis-carbon-content-factor)
- [Which coal line fits my coal's heat value?](https://senseible.earth/answers/which-ipcc-coal-line-fits-my-coal-gcv)
- [Pet coke emission factor in India](https://senseible.earth/answers/petcoke-emission-factor-india)
- [Will a buyer accept IPCC Tier 1 factors?](https://senseible.earth/answers/ipcc-tier-1-default-factor-good-enough)

Sources: [IPCC 2006 Guidelines, Volume 2, Chapter 1 (Table 1.4 and section 1.5.3)](https://www.ipcc-nggip.iges.or.jp/public/2006gl/vol2.html)

Last reviewed 2026-11-05. IPCC's consistency sentence is about national factors. Ask your buyer or verifier whether they accept the same test for a plant factor.