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Bioethanol and Combustion road vehicles

Almost all fuel ethanol is burned in petrol vehicles, so blending mandates such as India's E20 decide its market, while its lower energy content trims fuel economy by a few per cent.

Bioethanol (chemical) and Combustion road vehicles (energy): 4 relationships.

How they are linked

1. Energy flow

Physical flow · Strong · Bioethanol to combustion road vehicles

Fuel ethanol is made to be blended into petrol or burned in flex-fuel cars, so road vehicles are its main market.

  • about 10% ethanol by volume in most US petrol
  • 13.73 bn gallons fuel ethanol blended into US petrol, 2023

In the US, most petrol sold is about 10% ethanol by volume, so ethanol demand rises and falls with petrol use. Where a mandate sets the blend, as in India, the same holds at a higher ratio.

Sources: US Energy Information Administration

2. Blending mandates

Policy · High in India · Governments set how much ethanol goes into petrol

Blend rates are set by policy, not by drivers, so mandates such as India's E20 fix ethanol's share of the petrol pool.

  • 20% India's blend level, reached in 2025, five years ahead of the 2030 target
  • over Rs 1.97 lakh crore foreign exchange saved since 2014-15, as reported to Parliament in July 2026

India raised blending from about 1.5% in 2014 to 20% in 2025, and the oil ministry says this has displaced nearly 316 lakh tonnes of crude imports since 2014-15. The mandate turns vehicle petrol demand into assured ethanol demand for sugar and grain distilleries.

Sources: Mercom India (iamrenew); All India Radio News

3. Displaces petrol, at a fuel economy cost

Substitution · Medium · Ethanol replaces part of the petrol

Ethanol carries about a third less energy per litre than petrol, so a blended fuel moves a car a little less far per litre.

  • about 33% less energy in ethanol than petrol
  • 3 to 4% fewer miles per gallon on E10, US
  • 1 to 2% and 3 to 6% India ministry estimate of E20 mileage loss: E20-calibrated cars and others

The loss grows with the blend: flex-fuel cars on E85 go 15 to 27% fewer miles per gallon. India's oil ministry says vehicles designed for E10 and calibrated for E20 lose only about 1 to 2%, while others lose about 3 to 6%.

Sources: US Energy Information Administration; US Department of Energy and EPA, fueleconomy.gov; Business Today

4. Vehicle compatibility

Physical flow · Medium · Vehicles must be built or tuned for higher blends

Higher ethanol blends can wear some rubber parts and gaskets in older vehicles, so engines and fuel systems need suitable materials and calibration.

  • April 2023 since when E20-ready vehicles have been sold in India
  • 20,000 to 30,000 km after which some gaskets in older vehicles may need replacing

Indian makers have sold vehicles with E20-designed parts since April 2023, so the older fleet is where mileage and wear concerns sit; the ministry calls the gasket replacements low-cost routine servicing. A move to blends above 20% would raise the same compatibility question for the current fleet.

Sources: Business Today

For investors

Key learnings

  1. Ethanol demand is a set share of petrol demand fixed by mandates, so its volume follows petrol use and blend policy rather than price.
  2. A blend carries less energy per litre, about 3 to 4% less range on E10 and up to 6% on E20 in older Indian vehicles, which shapes public acceptance of higher blends.
  3. India's move to E20 in 2025 created a large, policy-backed market for distillers, with demand tied to the size of the petrol fleet.

What to track

  • India ethanol blend rate: Shows whether the 20% level holds or moves higher (Monthly · Ministry of Petroleum and Natural Gas, PPAC)
  • Ethanol procurement prices for oil marketing companies: Set distillers' revenue and the cost of blending (Each ethanol supply year · Ministry of Petroleum and Natural Gas, oil marketing companies)
  • US fuel ethanol blending volumes: The largest market's demand, tied to petrol use (Weekly · EIA)

For policymakers

Key learnings

  1. The government reported in July 2026 that blending had saved more than Rs 1.97 lakh crore of foreign exchange since 2014-15 by displacing imported crude.
  2. Mileage losses of 3 to 6% in vehicles not calibrated for E20 are a real cost for owners, so clear labelling and compatibility rules matter.
  3. Any move beyond E20 needs vehicle standards and fleet turnover planned in advance.

What to track

  • Share of the vehicle fleet certified E20 compatible: Shows how far higher blends can go without wear or mileage complaints (Annually · SIAM and Ministry of Road Transport)
  • Crude imports displaced by ethanol: The import saving the programme delivers (Annually · Ministry of Petroleum and Natural Gas)

India

India reached 20% ethanol in petrol in 2025, five years ahead of its 2030 target, and reported foreign exchange savings of more than Rs 1.97 lakh crore since 2014-15; E20-ready vehicles have been sold since April 2023, while older ones may lose 3 to 6% in mileage.

Sources

  1. How much ethanol is in gasoline, and how does it affect fuel economy?, US Energy Information Administration (2024)
  2. Ethanol, US Department of Energy and EPA, fueleconomy.gov
  3. No damage to engines but mileage sees slight dip: govt clarifies on E20 fuel concerns, Business Today (2025)
  4. Ethanol blending programme saved India Rs 1.97 lakh crore: Suresh Gopi, Mercom India (iamrenew) (2026)
  5. India hits 20% ethanol blending in petrol 5 years ahead of target: Union Minister Hardeep Singh Puri, All India Radio News (2025)