Bioethanol: Emissions
How much CO2 ethanol really saves, crop by crop
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 1.20 t CO2e per t range about 0.6-2.0: cane (RED default 28 g CO2e/MJ) about 0.76; EU maize default 49 g/MJ about 1.31; California average ethanol 59 g/MJ including ILUC about 1.58; add 0.32-0.35 for EU ILUC estimates · indicative world average of about 45 g CO2e/MJ weighted by RFA 2025 country output, x 26.8 GJ/t; petrol comparator 94 g/MJ, i.e. 2.52 t per t of ethanol energy-equivalent Global emissions per year 115 Mt CO2e per year 2025 · 1.2 t/t x 96 Mt fuel ethanol (indicative); against petrol this avoids about 125 Mt CO2e (derived: (94-45) g/MJ x 2.56 EJ)Per t of fuel ethanol, life cycle (well-to-wheel per MJ x 26.8 GJ/t); combustion CO2 is biogenic and counted as zero. Intensity: RED II Annex V (EU 2018/2001); CARB LCFS 2022 average CIs (CARB board presentation, Sep 2023); RED II Annex VIII ILUC (cereals 12, sugars 13 g/MJ) (indicative). Global total: derived from RFA 2025 and RED/CARB values (indicative).
Share of footprint by lifecycle phase
Feedstock 55% Production / process 40% Movement 4% Use 1%Footprint by lifecycle phase
| Phase | Intensity | Share | Main sources of emissions | Notes | Source |
|---|---|---|---|---|---|
| Feedstock | about 0.6-0.7 t CO2e/t (farming, fertiliser N2O, plus ILUC where counted) | 55% | nitrogen fertiliser and N2O, diesel, cane burning; land-use change | CARB adds 19.8 g/MJ ILUC for US maize ethanol (indicative); EU ILUC estimate 12 g/MJ cereals, 13 g/MJ sugars | RED II Annex VIII; CARB LCFS (indicative) |
| Production / process | about 0.4-0.5 t CO2e/t for grain plants on gas; near zero fossil for cane mills burning bagasse | 40% | steam for distillation and drying DDGS; coal-fired boilers in some Indian and Chinese plants | fermentation CO2 (about 0.95 t per t ethanol) is biogenic and nearly pure, so capture is cheap | indicative |
| Movement | about 0.03-0.06 t CO2e/t | 4% | rail, barge and ocean freight | small except for long-haul exports | indicative |
| Use | about 0.01 t CO2e/t (non-CO2 tailpipe gases) | 1% | CH4 and N2O from combustion | combustion CO2 is biogenic; aldehyde emissions rise slightly | indicative |
| End of life | not applicable | – | fuel is burned | not applicable | not applicable |
Other environmental impacts
Grain and cane ethanol compete with food and feed: India's maize demand for ethanol tightened poultry feed supply and FCI rice sales cost about 40% below acquisition (rice tile). Cane needs water and vinasse must be managed; field burning of cane and straw adds air pollution.
Levers to cut emissions
- Carbon capture of fermentation CO2 (about 0.95 t per t ethanol, nearly pure) for storage or e-fuels
- Biomass or biogas instead of coal or gas for process steam
- Low-CI farming: lower nitrogen use, no-till, cover crops (credited under 45Z and LCFS)
- Cellulosic ethanol from residues to avoid land-use change
- Higher plant yields and corn oil extraction
India
India's ethanol footprint now depends mainly on maize and FCI rice, which carry more fossil input than cane juice; no official Indian life-cycle values are published for each feedstock. Blending E20 displaces petrol but the 2026-27 shift away from cane raises the average carbon intensity (indicative).
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 |
|---|---|---|---|---|
| Grain ethanol with CO2 capture and storage | can fall below 20-30 g CO2e/MJ (indicative) | capture is cheap (pure stream); transport and storage dominate | US Midwest projects tied to pipelines and Class VI wells; Red Trail Energy in North Dakota operates storage (indicative) | indicative |
| Cellulosic (2G) ethanol from bagasse or rice straw | about 10-20 g CO2e/MJ (indicative) | well above 1G ethanol (indicative) | Raízen bagasse plants in Brazil; Indian Oil Panipat straw plant (indicative) | indicative |
| Alcohol-to-jet SAF | depends on ethanol CI (indicative) | SAF costs about 2x fossil jet (IATA Dec 2025) | LanzaJet Freedom Pines (US) and others (indicative) | IATA Dec 2025; indicative |