Which methane factor should a kiln or dryer use: the general manufacturing figure or the kiln and dryer table in the Intergovernmental Panel on Climate Change guide?
The Intergovernmental Panel on Climate Change (IPCC) 2006 Guidelines give kilns and dryers 1.0 to 1.1 kilograms of methane (CH4) per terajoule (TJ) for coal, oil or gas, against 10 for coal in the general manufacturing table. The kiln table is a technology table for the more detailed Tier 3 method.
The kiln, oven and dryer table, kilograms of CH4 per TJ
- Cement and lime kilns: natural gas 1.1, oil 1.0, coal 1.0.
- Coking and steel, coke oven: 1.0.
- Dryers in chemical processes, wood, asphalt, copper and phosphate: natural gas 1.1, oil 1.0, coal 1.0.
- Nitrous oxide: shown as not available for every line.
The general manufacturing table, for comparison
- Other bituminous coal: methane 10, nitrous oxide 1.5.
- Gas or diesel oil, and residual fuel oil: 3 and 0.6.
- Petroleum coke: 3 and 0.6.
- Natural gas: 1 and 0.1.
How to choose
The guide's Tier 3 approach splits fuel use by technology and uses factors that depend on those differences; the kiln table is one of its technology tables. The guide gives its Tables 2.6 to 2.10 as examples of representative factors, a starting point or a comparison, not as fixed defaults. If your records give fuel burnt in kilns and dryers separately from boilers, the kiln table fits. If you only have one fuel total for the site, the general table is the Tier 1 default.
The kiln table has no nitrous oxide figure, so that gas needs another source, such as the general table. Its values were converted from gross to net calorific basis by assuming net is 5% lower for coal and oil and 10% lower for natural gas.
What this does not cover
Carbon dioxide released from the stone in a lime or cement kiln is a process figure, calculated separately. See the lime page.
A lime kiln burning 40 TJ of coal a year (example quantity)
- Fuel carbon dioxide (CO2) at 94,600 kilograms per TJ: 40 x 94,600 = 3,784,000 kilograms, or 3,784 tonnes
- Methane, general table: 40 x 10 = 400 kilograms. Kiln table: 40 x 1.0 = 40 kilograms
- At an example global warming potential of 28: 11.2 tonnes of CO2 equivalent against 1.1
The 40 TJ and the factor of 28 are example numbers. Stone CO2 is extra.
What Senseible does here
Senseible reads fuel invoices and electricity bills into monthly records, so coal, petroleum coke and gas bought are on file each month. Splitting kiln fuel from boiler fuel needs your own meter or stock records.
- Free calculators
- Default emission factor for lime, by lime type
- Same fuel, different methane by sector table
Last reviewed 2026-11-04. Factors are from the 2006 IPCC Guidelines, which cite 1990 and 2005 sources. Confirm the table choice with your verifier.