# Biogas and biomethane: Emissions

How manure gas can score below zero on carbon

Source page: https://www.materialinsights.org/energy/biomethane/emissions/

What this tab covers The greenhouse-gas footprint per tonne, split by lifecycle phase (feedstock, production, movement, use, end of life), the global total, other environmental impacts, levers and low-carbon routes, India's position, and where the investment opportunity lies. Emission intensity 1.00 t CO2e per t range about -10 (manure with methane capture; California in-state bio-CNG averaged -198 g/MJ in 2025) to about 1.5-2.5 for energy-crop biomethane with high methane slip; fossil CNG about 3.5-4 t per t (indicative) · indicative 20 g CO2e/MJ for a waste and residue mix without manure credit, x 50 GJ/t Global emissions per year 32.0 Mt CO2e per year 2024 · 1.0 t/t x about 32 Mt methane in about 45 bcm biogas and biomethane (indicative); manure and landfill capture avoid far more

Per t of biomethane (per MJ x 50 GJ/t), life cycle; combustion CO2 is biogenic; shown excluding the avoided-methane credit for manure. Intensity: Transport Project, RNG in California 2025 (Jun 2026, CARB LCFS data); RED II Annex VI and CARB LCFS pathways (indicative). Global total: derived (indicative).

#### Share of footprint by lifecycle phase
 Feedstock 15% Production / process 60% Movement 20% Use 5%

#### Footprint by lifecycle phase

| Phase | Intensity | Share | Main sources of emissions | Notes | Source |
|---|---|---|---|---|---|
| **Feedstock** | zero burden for wastes; about 0.5-1 t CO2e/t for energy crops (indicative) | 15% | silage cultivation and fertiliser; manure storage before digestion | manure digestion avoids lagoon methane, which credit systems count as a negative emission | indicative |
| **Production / process** | about 0.6 t CO2e/t | 60% | methane leaks from digesters (0-12%) and upgrading (0.2-10%), digestate storage, power and heat | leak ranges are for European plants (IEA 2025); each 1% methane slip adds about 0.3 t CO2e per t biomethane at GWP100 30 (derived) | IEA Outlook for Biogas and Biomethane (May 2025), via World Biogas Association and BioCycle |
| **Movement** | about 0.2 t CO2e/t | 20% | compression to 200-250 bar, trucking cascades, grid losses | low for grid injection, higher for India's cascade logistics | indicative |
| **Use** | about 0.05 t CO2e/t | 5% | unburnt methane from engines | combustion CO2 is biogenic | indicative |
| **End of life** | not applicable to the gas; digestate spreading emits N2O and ammonia | – | digestate handling | covered storage and injection into soil reduce emissions; digestate replaces mineral fertiliser | European Biogas Association Statistical Report 2025, via Renewable Energy Magazine, 10 Dec 2025 |

#### Other environmental impacts

Cuts open burning of paddy straw and untreated dung; digestate replaces fertiliser (Europe 25 Mt dry matter, 17% of EU nitrogen fertiliser equivalent). Odour, ammonia and H2S safety risks; energy crops compete for land.

#### Levers to cut emissions

- Manure and food-waste feedstocks with methane credits
- Leak detection and repair, covered digestate storage and off-gas combustion
- Capturing and selling upgrading CO2 (food grade or for e-methanol)
- Renewable power for compression
- Digestate replacing urea (IEA: about 10% of India's fertiliser need by 2050 with full use)

#### India

India's main climate gains are avoided stubble burning and dung methane plus displaced imported LNG; the IEA says digestate could meet about 10% of India's projected fertiliser needs by 2050 (World Biogas Association summary, 2025).
 Emission figures are indicative global averages from the life-cycle studies named; actual footprints vary widely by site, energy mix and method.

#### Low-carbon routes

| Route | Intensity | Cost premium | Status | Source |
|---|---|---|---|---|
| **Dairy manure RNG with methane capture** | California in-state bio-CNG averaged -198 g CO2e/MJ in 2025 | relies on LCFS and RIN credits | 98% of California on-road natural gas vehicle fuel is RNG; 7.9 Mt CO2e avoided in 2025 | Transport Project, RNG in California 2025 (Jun 2026, CARB LCFS data) |
| **Paddy straw CBG in Punjab and Haryana** | low (residue that would be burned; indicative) | straw logistics add cost (indicative) | commercial plants such as Verbio's in Punjab and OMC-backed units (indicative) | indicative |

 For a climate investor India's CBG obligation turns biomethane into a mandated market of roughly 1.75 MMSCMD by 2028-29 (derived from the 1% = 0.35 MMSCMD rule), against about 0.65 MMSCMD sold today. The investable pieces are plants near press mud, dairy clusters and paddy straw, feedstock aggregation, digestate marketing and upgrading equipment. What has to be true: bankable offtake at 85% of CNG retail, reliable feedstock contracts and leak control. Reliance, Adani TotalEnergies, Petronet-Gruner and the OMCs are building.

## Other sections

- [Summary](https://www.materialinsights.org/energy/biomethane/index.md)
- [Energy overview](https://www.materialinsights.org/energy/biomethane/energy/index.md)
- [Correlation](https://www.materialinsights.org/energy/biomethane/correlation/index.md)
- [Efficiency](https://www.materialinsights.org/energy/biomethane/efficiency/index.md)
- [Techniques](https://www.materialinsights.org/energy/biomethane/techniques/index.md)
- [Resources and labour](https://www.materialinsights.org/energy/biomethane/resources/index.md)
- [Impact on the biosphere](https://www.materialinsights.org/energy/biomethane/biosphere/index.md)
- [Overview](https://www.materialinsights.org/energy/biomethane/overview/index.md)
- [Production route](https://www.materialinsights.org/energy/biomethane/routes/index.md)
- [Production](https://www.materialinsights.org/energy/biomethane/production/index.md)
- [Feedstocks](https://www.materialinsights.org/energy/biomethane/feedstocks/index.md)
- [Cycles](https://www.materialinsights.org/energy/biomethane/cycles/index.md)
- [Trading](https://www.materialinsights.org/energy/biomethane/trading/index.md)
- [Movement](https://www.materialinsights.org/energy/biomethane/movement/index.md)
- [Regulation](https://www.materialinsights.org/energy/biomethane/regulation/index.md)
- [Characteristics](https://www.materialinsights.org/energy/biomethane/characteristics/index.md)
- [Relationships](https://www.materialinsights.org/energy/biomethane/links/index.md)