GS2 INTERNATIONAL RELATIONS
After technical challenges halted India’s earlier attempts to blend ethanol with diesel, the Union Ministry of Road Transport and Highways, in collaboration with the Automotive Research Association of India (ARAI), has now initiated a feasibility study on isobutanol–diesel blending. This move aims to utilise surplus biofuel production and support India’s clean energy targets.
Why Isobutanol?
Isobutanol is considered a better blending option for diesel when compared to ethanol due to:
- Higher flash point → makes it safer for storage and transport
- Lower volatility → reduces vapour lock and safety hazards
- Greater miscibility potential with diesel fuels
It is produced biologically through fermentation of sugarcane syrup, molasses, and grain feedstock using engineered microbes.
Economic Context
- The Indian Sugar Mills Association (ISMA) reports that ethanol supply has already exceeded demand.
- Surplus ethanol is causing a supply glut and price stagnation, impacting sugar mills.
- Isobutanol blending is seen as a new revenue option for the sugar industry.
- Sugar industry has demanded a revision in ethanol procurement prices due to increasing cane production costs.
Technical Challenges
Despite its potential, isobutanol poses engineering and fuel compatibility issues:
| Challenge | Concern |
| Low cetane number | Poor ignition efficiency |
| Miscibility issues | Partial blending with diesel |
| Engine knock risk | Fuel instability may damage engines |
- Researchers suggest using biodiesel as a stabilising agent to improve fuel compatibility.
- Additives may enhance cetane rating, but increase production costs.
Feasibility and Pilot Testing
- ARAI is conducting an 18-month pilot project to evaluate large-scale blending feasibility.
- The project will assess engine performance, emissions, and logistics.
- If successful, India could become the first country to adopt diesel–isobutanol blending commercially.
Industrial & Environmental Impact
- Minimal retrofitting required in existing distilleries → sugar factories can produce 125 KLPD of ethanol + 20 KLPD of isobutanol.
- Supports import substitution of fossil fuels.
- Can lower vehicular emissions and contribute to India’s 2070 net-zero commitment.
- Boosts energy security under Atmanirbhar Bharat.