What emissions must a composting project deduct under CCTS tool BM-T-013?
Methane and nitrous oxide from the compost, power and fuel used, and methane from run-off in co-composting. Without measurements, BM-T-013 sets 0.002 t of methane and 0.0002 t of nitrous oxide per tonne of wet waste, 0.01 MWh of power and 0.0207 t CO2 from fuel.
What is counted
- Methane and nitrous oxide from the composting process.
- CO2 from fossil fuel and electricity used for composting.
- Methane from run-off wastewater in co-composting. It is zero if run-off is collected and recirculated, as in tunnel co-composting.
- Leakage if compost is dumped or stored anaerobically, worked out with BM-T-011. Compost used as landfill cover is not leakage, and transport is not counted.
Weighing the waste
Use a calibrated weighbridge or belt scale. Without one, add up the nameplate carrying capacity of every truck delivering waste. For household, community and SME projects, a weighbridge gap of up to 30 consecutive days in six months can be filled from truck capacities or the highest figure for the same period in earlier years.
Measuring instead of defaults
Measure at least three composting cycles a year. In closed halls, measure the exhaust pipe or use BM-T-005. For windrows, use a flux box at at least 10 sites per windrow, two cross sections of five points, with at least five measurement events per site, so 50 or more readings per cycle.
Run-off defaults
Methane = COD in the run-off x 0.25 t methane per t COD x the treatment system's methane conversion factor x 1.12. If you only monitor the wastewater you co-compost, run-off COD can be taken as 0.02 of its COD. The conversion factor is 0 for well managed aerobic treatment, 0.8 for anaerobic reactors or deep lagoons without recovery, and 1 if unknown.
Worked example: 10,000 t of wet waste a year
- Methane: 10,000 x 0.002 = 20 t x 29.8 = 596 t CO2e
- Nitrous oxide: 10,000 x 0.0002 = 2 t x 273 = 546 t CO2e
- Fuel: 10,000 x 0.0207 = 207 t CO2
- Power: 10,000 x 0.01 = 100 MWh, at the grid factor BM-T-003 sets
- Total before power: 1,349 t CO2e a year to deduct
BM-T-013 leaves the GWP blank; 29.8 is the methane value BEE applies in BM-T-008 and 273 is the IPCC AR6 value for nitrous oxide. Use what your methodology version sets.
What Senseible does here
Senseible gives carbon credit eligibility signals from your records; it does not register projects or issue credits. It keeps dated, fingerprinted fuel and electricity invoices that a project's monitoring records can draw on.
Sources: BEE, BM-T-013 Project and leakage emissions from composting (CCTS Offset Mechanism, version 1.0, 27 March 2025): data and parameter tables 1 to 14, IPCC AR6 Working Group I, global warming potentials, BEE, Methodologies and Tools under the CCTS Offset Mechanism
Last reviewed 2026-10-25.