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Ethanol blending in diesel fails flash-point test, says Government

Samira Vishwas | August 11, 2026 4:24 PM CST

After making the much-debated E20 the standard petrol across India, the Centre has been planning to blend biofuel into diesel. However, the government has said that the ethanol blending in diesel has failed the flash-point test. Ethanol-blended diesel failed the required safety specifications before the addition of ethanol sharply lowered the fuel’s flash point, said Minister of State for Petroleum and Natural Gas Suresh Gopi. He effectively ruled out the fuel for wider use unless the technical issue is resolved.

In a written response to Parliament, the minister said that public-sector oil marketing companies conducted scientific evaluations of ethanol blending with diesel through their research and development centres, in collaboration with accredited laboratories and automobile manufacturers.

The tests found that ethanol-blended diesel did not meet the required diesel flash-point specification because the flash point fell sharply in the presence of ethanol, he said. “Scientific evaluations on blending of ethanol with diesel have been undertaken by Public Sector Oil Marketing Companies (OMCs) through their respective R&D centres in collaboration with accredited laboratories and automobile manufacturers. It was observed that ethanol blended diesel was not meeting diesel flash point as its flash point lowered drastically due to the presence of ethanol,” the minister said.

This finding comes as the Government of India seeks to expand the use of ethanol as a transport fuel and explore new outlets for rising domestic production. The government has so far focused its ethanol blending programme on petrol. When asked about blending isobutanol in diesel, the minister said that it is not being blended with diesel presently.

Gopi also said no decision has been taken to raise ethanol blending in petrol beyond 20%. Any future increase would be considered only after detailed scientific and technical studies and consultations with automobile manufacturers, oil marketing companies and research institutions.