MTBE: Emissions
Most carbon is released when the petrol burns
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 1.50 t CO2e per t range 0.8-2.0 · 0.364 t methanol at 2.6 t CO2e/t (about 0.95; methanol tile, IEA-derived) plus isobutylene from FCC or dehydrogenation (about 0.3-0.8) plus etherification energy Global emissions per year 47.0 Mt CO2e per year (cradle-to-gate) 2024 · 1.5 t x about 31 Mt; combustion adds about 2.5 t CO2 per t, or about 78 MtPer t of MTBE, cradle-to-gate. Intensity: derived from methanol tile (indicative). Global total: derived (indicative).
Share of footprint by lifecycle phase
Feedstock 87% Production / process 10% Movement 3%Footprint by lifecycle phase
| Phase | Intensity | Share | Main sources of emissions | Notes | Source |
|---|---|---|---|---|---|
| Feedstock | about 1.3 t CO2e/t (methanol about 0.95, isobutylene about 0.35) | 87% | coal versus gas methanol; on-purpose dehydrogenation versus refinery C4 | allocation of refinery emissions to C4s varies | derived (indicative) |
| Production / process | about 0.15 t CO2e/t | 10% | distillation steam | reaction is exothermic | indicative |
| Movement | about 0.05 t CO2/t | 3% | product tankers | US to Mexico short haul | indicative |
| Use | 2.5 t CO2 per t burned (stoichiometry: 5 CO2 per molecule) | – | combustion in petrol engines | fossil carbon; ETBE from bio-ethanol has partly biogenic carbon | stoichiometry |
| End of life | not applicable (fully combusted) | – | leaks to groundwater | groundwater contamination is the main non-climate impact | indicative |
Other environmental impacts
Groundwater contamination from leaking tanks (the reason for US bans); MTBE is persistent and mobile in water. It can reduce tailpipe CO and hydrocarbons in older engines.
Levers to cut emissions
- Bio-methanol or e-methanol feed
- Switch to ETBE from low-carbon ethanol
- Reduce petrol demand through electrification
- Efficient catalytic distillation
India
India's MTBE footprint is small and refinery-embedded; E20 ethanol blending is replacing part of the octane role, with a lower fossil footprint where ethanol comes from sugarcane molasses or grain.
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 |
|---|---|---|---|---|
| ETBE from bio-ethanol | lower than MTBE because about 45% of carbon is biogenic (indicative) | depends on ethanol price (indicative) | growing in Europe, notably Italy (S&P Global) | S&P Global (H1 2026 trends); indicative |
| MTBE from bio-methanol | about 20% lower (indicative, basis: methanol is about 36% of mass and part of the footprint) | bio-methanol premium (IRENA 2021, indicative) | not found at commercial scale | indicative |