ARAI and Praj industries begin 10-month isobutanol-diesel validation program in India

India's Automotive Research Association (ARAI) and Praj Industries will lead a 10-month validation program starting June 2025. The initiative aims to assess isobutanol as a viable diesel additive. Major original equipment manufacturers (OEMs) and oil companies will participate. Early tests show a 5% isobutanol blend can reduce emissions while causing only a 1 to 2% drop in fuel efficiency.

Key Highlights

• ARAI and Praj Industries will lead a 10-month isobutanol-diesel validation program from June 2025
• Early tests show a 5 percent isobutanol blend cuts emissions with minimal fuel efficiency loss
• Major OEMs and oil companies, including BPCL, are participating in nationwide trials
• Isobutanol offers better chemical compatibility and safety compared to ethanol for diesel blending
• Government incentives may support retrofitting ethanol plants for isobutanol production

Isobutanol as a Diesel Additive

The Indian automotive sector is seeking solutions for diesel decarbonization with other lubricants as well. The new program will evaluate isobutanol blending across commercial vehicle OEMs, ARAI, the Council of Scientific and Industrial Research (CSIR), and oil marketing companies. The focus is on finding a stable, safe, and effective diesel alternative for India's transport fleet.

Previous attempts to blend ethanol with diesel failed due to chemical incompatibility. Ethanol's polar structure prevents it from mixing well with diesel, and its low flashpoint of 12 to 13 degrees Celsius poses safety risks. Diesel's minimum regulated flashpoint is 35 degrees Celsius, making ethanol blends difficult to store and transport safely. Even with chemical binders, ethanol blends rarely exceeded 5% without combustion issues.

Praj Industries has developed isobutanol, a four-carbon alcohol, as a potential solution. Isobutanol's flashpoint of 27 to 30 degrees Celsius keeps it within the same safety category as diesel. This compatibility means existing storage and transport infrastructure can be used without major changes. Stability tests show isobutanol blends remain mixed for over 40 days at 10% concentration.

Testing and Industry Participation

Initial chassis dynamometer trials on Indian driving cycles found that a 5% isobutanol blend reduced emissions with only a minor impact on fuel economy. The upcoming ARAI-led assessment will examine engine durability, material compatibility, and particulate emissions across various OEMs. Oil companies are also investing in the project. BPCL has conducted two years of isobutanol testing, including a recent three-month trial with stationary Cummins engines. BPCL plans to expand testing to 33 vehicle types.

However, large-scale adoption depends on government policy. Oil marketing companies require a formal mandate to blend isobutanol at scale. There is also discussion about converting existing first-generation (1G) ethanol plants to produce both ethanol and isobutanol. Industry experts suggest a hybrid model, allowing simultaneous production of both fuels from the same feedstock.

Policy and Market Outlook

The government may extend financial incentives, such as the Scheme to Enhance Ethanol Distillation Capacity and the PM JI-VAN Yojana, to support isobutanol production. These schemes could help retrofit existing facilities and encourage commercial-scale projects. Despite promising results, the isobutanol market is still emerging. Industry leaders urge caution in setting commercial timelines but see potential for significant progress as the validation program begins.

Also Read: LANXESS and HPCL joins hands to boost lubricant reach across India and SAARC

CarBike 360 Says

The collaboration between ARAI and Praj Industries marks a significant step toward diversifying India’s fuel ecosystem with cleaner alternatives. If successful, the validation program could pave the way for large-scale adoption of isobutanol-diesel blends, reducing emissions and dependence on conventional fuels. This initiative reinforces India’s broader push toward sustainable mobility and innovative biofuel solutions.