Methodology
How the numbers are calculated
Every result comes from a fixed formula and a stored emission factor. The same inputs always give the same answer, and every factor is listed with its source, year and boundary.
Food composition to methane
The separate food-load calculator estimates theoretical methane from net wet food component masses multiplied by frozen IEA Bioenergy Task 37 (2018), Food Waste Digestion, Table 4 coefficients, including cellulose as an explicitly assumed fibre surrogate. These are published rounded values, not exact chemical derivations; the table’s lipid formula is inconsistent with its printed coefficient. Label rounding, chemistry and biological accessibility introduce uncertainty. Gas volumes refer to the model’s declared reference conditions, not raw biogas volume.
Theoretical represented-component potential
Σ(net wet component kg × component methane yield m³/kg)
Confirmed-component mode includes separately identified nutrients only. In the optional UK/EU-label scenario, sugars use a glucose surrogate, carbohydrate minus sugars is assumed starch-like, and separately declared fibre is assumed cellulose. Sugars are never added on top of full carbohydrate; fibre is not subtracted from UK/EU carbohydrate. These assumptions require confirmation; unresolved polyols, US labels and lignin-rich/enriched fibre are unsupported. CoFID measured starch uses 162/180 conversion only. Serving values need serving mass; per-100-ml values need measured density.
Packaging sample
container tonnes = product count × measured empty-container grams ÷ 1,000,000
Pallets and outer wrap are accounted for separately. Gross collected mass drives transport; net food drives methane. A source-backed facility profile supplies expected conversion, capture and upgrading retention. AD first produces biogas; biomethane is the upgraded methane-rich product. The recovered figure is methane content, not assumed gas purity.
Leakage-only CO₂e is a separate memo, never added to a factor that already includes leakage. Whole-load carbon remains unavailable without required AD and packaging-disposal evidence. AD is not automatically carbon negative; avoided credits are never silently deducted.
IEA Bioenergy: Food Waste Digestion (2018)The formulas
Treatment
tonnes × treatment factor (kg CO₂e per tonne)
Transport
tonnes × one-way distance (km) × vehicle factor (kg CO₂e per tonne-km)
Total
treatment + transport
Change
alternative total − current total; % = change ÷ current total
Miles are converted at 1 mile = 1.609344 km. A percentage is only shown when the current total is above zero.
Transport: one-way distance, allocated by weight
Enter the one-way distance from where the waste is collected to the treatment facility. Published DESNZ 2026 diesel non-refrigerated HGV factors combine direct combustion (TTW) and upstream fuel production (WTT). Tonne-km allocation uses national fleet loading and empty-running assumptions; do not separately double the distance for an assumed return. Vehicle weight bands are not payload; factors exclude vehicle manufacture, infrastructure, refrigeration and specialised refuse collection. The vehicle's emissions are shared out by the weight of this waste (tonne-km), so a part-load only carries its share.
If the alternative facility is further away or closer, you can enter a different one-way distance for it.
Keeping things separate and consistent
- Treatment, transport and avoided emissions are calculated and shown separately.
- Avoided emissions (e.g. from recovered materials or energy) are a memo item only and are never subtracted from totals, to prevent double counting.
- If a treatment factor already includes transport, separate transport is not added.
- Routes are only compared when both factors share the same calculation boundary.
- No route — including recycling — is assumed to be lower-carbon. Increases are shown clearly.
- Where a suitable factor doesn't exist, the result reads “Calculation unavailable”.
- Saved assessments keep the exact factor version they used. Newer factors only apply after an explicit recalculation.
Current factor set
Published DESNZ 2026 fuel-chain HGV transport; IEA component surrogate methane screening. No verified treatment factors or compatible average-plant recovery/carbon scenario. Estimates, not certification.
| Waste type | Landfill | Incineration with energy recovery | Recycling | Composting | Anaerobic digestion |
|---|---|---|---|---|---|
| Food waste | Not available | Not available | Not available | Not available | Not available |
| Dairy | Not available | Not available | Not available | Not available | Not available |
| Meat | Not available | Not available | Not available | Not available | Not available |
| Poultry | Not available | Not available | Not available | Not available | Not available |
| Fish and seafood | Not available | Not available | Not available | Not available | Not available |
| Fruit | Not available | Not available | Not available | Not available | Not available |
| Vegetables | Not available | Not available | Not available | Not available | Not available |
| Bread and bakery | Not available | Not available | Not available | Not available | Not available |
| Biscuits/snacks | Not available | Not available | Not available | Not available | Not available |
| Rice, pasta and cereals | Not available | Not available | Not available | Not available | Not available |
| Confectionery | Not available | Not available | Not available | Not available | Not available |
| Oils and fats | Not available | Not available | Not available | Not available | Not available |
Values in kg CO₂e per tonne of waste (treatment only).
Transport factors
8 wheel roll on offDESNZ 2026 full set: https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2026 ; https://assets.publishing.service.gov.uk/media/6a29392bade52dc0882218a8/ghg-conversion-factors-2026-full-set.xlsx
Diesel non-refrigerated average-laden HGV; TTW+WTT operational fuel chain, national loading/empty-running assumptions; excludes vehicle manufacture/infrastructure, refrigeration and specialised refuse collection.
Freighting goods!D48 TTW 0.17256 + WTT- delivery vehs & freight!D43 WTT 0.03736 = 0.20992. One-way tonne-km; vehicle weight class is not payload. Factor class: rigid HGV over 17 t, average laden.0.21 kg CO₂e / tonne-km
8 wheel TipperDESNZ 2026 full set: https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2026 ; https://assets.publishing.service.gov.uk/media/6a29392bade52dc0882218a8/ghg-conversion-factors-2026-full-set.xlsx
Diesel non-refrigerated average-laden HGV; TTW+WTT operational fuel chain, national loading/empty-running assumptions; excludes vehicle manufacture/infrastructure, refrigeration and specialised refuse collection.
Freighting goods!D48 TTW 0.17256 + WTT- delivery vehs & freight!D43 WTT 0.03736 = 0.20992. One-way tonne-km; vehicle weight class is not payload. Factor class: rigid HGV over 17 t, average laden.0.21 kg CO₂e / tonne-km
Artic box/curtainDESNZ 2026 full set: https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2026 ; https://assets.publishing.service.gov.uk/media/6a29392bade52dc0882218a8/ghg-conversion-factors-2026-full-set.xlsx
Diesel non-refrigerated average-laden HGV; TTW+WTT operational fuel chain, national loading/empty-running assumptions; excludes vehicle manufacture/infrastructure, refrigeration and specialised refuse collection.
Freighting goods!D57 TTW 0.07835 + WTT- delivery vehs & freight!D52 WTT 0.01799 = 0.09634. One-way tonne-km; vehicle weight class is not payload. Factor class: articulated HGV, 33-44t gross weight class (covers standard 44t artics), average laden.0.096 kg CO₂e / tonne-km
Artic TipperDESNZ 2026 full set: https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2026 ; https://assets.publishing.service.gov.uk/media/6a29392bade52dc0882218a8/ghg-conversion-factors-2026-full-set.xlsx
Diesel non-refrigerated average-laden HGV; TTW+WTT operational fuel chain, national loading/empty-running assumptions; excludes vehicle manufacture/infrastructure, refrigeration and specialised refuse collection.
Freighting goods!D57 TTW 0.07835 + WTT- delivery vehs & freight!D52 WTT 0.01799 = 0.09634. One-way tonne-km; vehicle weight class is not payload. Factor class: articulated HGV, 33-44t gross weight class (covers standard 44t artics), average laden.0.096 kg CO₂e / tonne-km
Small van up to 7.5tDESNZ 2026 full set: https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2026 ; https://assets.publishing.service.gov.uk/media/6a29392bade52dc0882218a8/ghg-conversion-factors-2026-full-set.xlsx
Diesel non-refrigerated average-laden HGV; direct fuel combustion plus upstream fuel production (TTW+WTT), allocated per tonne-km using national fleet loading/empty-running assumptions. Excludes vehicle manufacture and infrastructure; not bespoke refuse collection or refrigeration.
Freighting goods!D42 TTW 0.54001 + WTT- delivery vehs & freight!D37 WTT 0.12296 = 0.66297. Vehicle band is vehicle weight class, not payload. One-way laden distance; do not separately double for an assumed empty return.0.663 kg CO₂e / tonne-km
4 wheel skip vehicleDESNZ 2026 full set: https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2026 ; https://assets.publishing.service.gov.uk/media/6a29392bade52dc0882218a8/ghg-conversion-factors-2026-full-set.xlsx
Diesel non-refrigerated average-laden HGV; TTW+WTT operational fuel chain, national loading/empty-running assumptions; excludes vehicle manufacture/infrastructure, refrigeration and specialised refuse collection.
Freighting goods!D45 TTW 0.43002 + WTT- delivery vehs & freight!D40 WTT 0.09246 = 0.52248. One-way tonne-km; vehicle weight class is not payload.0.522 kg CO₂e / tonne-km
6 wheel skip vehicleDESNZ 2026 full set: https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2026 ; https://assets.publishing.service.gov.uk/media/6a29392bade52dc0882218a8/ghg-conversion-factors-2026-full-set.xlsx
Diesel non-refrigerated average-laden HGV; TTW+WTT operational fuel chain, national loading/empty-running assumptions; excludes vehicle manufacture/infrastructure, refrigeration and specialised refuse collection.
Freighting goods!D48 TTW 0.17256 + WTT- delivery vehs & freight!D43 WTT 0.03736 = 0.20992. One-way tonne-km; vehicle weight class is not payload.0.21 kg CO₂e / tonne-km
Known gaps
- Category-specific food treatment factors may be unavailable; generic food factors are not substituted.
- Label surrogates are theoretical scenarios, not measured BMP. Unresolved components require measured-component mode; missing required inputs stay unavailable.
- No compatible average-plant recovery/carbon profile was established from IEA, MEAD or DESNZ reporting factors. Their different denominators and boundaries cannot be combined as defaults. Future supported averages must be labelled and explicitly confirmed as applicable; packaging disposal remains separate.
Before using results for reporting
New calculations use published UK transport factors and a sourced theoretical nutrition scenario, not demonstration transport. Treatment and plant-dependent estimates remain unavailable without matching evidence. Older frozen reports can still contain demonstration factors; only explicit recalculation changes them. A sourced factor set does not certify a food-label scenario or complete carbon footprint. Results remain estimates and are not certified or independently verified.