Ethanol Blended Diesel Does Not Meet Existing Diesel Flash Point Safety Standards

The Minister of State for Petroleum and Natural Gas, Suresh Gopi, on Monday, revealed to Parliament that state-owned Oil Marketing Companies, in association with laboratories and vehicle manufacturers, had carried out testing on ethanol-blended diesel. The results showed that the fuel at present did not meet existing diesel flash point safety standards, thus ruling out the use of the fuel in the near future.

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Gopi stated that ethanol blending reduced the flash point of the diesel fuel mix to below that of regular diesel. Flash point testing is a critical safety test undertaken to study the combustibility of fuel mixes. Fuels with low flash points require lower peak temperatures in order to combust and vice versa. While full details of the tests have not been revealed, a lower flash point for diesel-ethanol blend could cause significant issues regarding transport and storage, not to mention premature combustion if used in existing diesel engines.

The results of the tests arrive at a time when questions have been raised around the Government’s present petrol-ethanol blending program. E20 blended petrol was rolled out in a phased manner across India starting in 2025, with the fuel replacing regular petrol entirely as of early 2026. The government furthermore also rolled out E85 flex fuel (comprising 85 per cent ethanol) earlier this year.

E20 petrol has come under fire over reports of damage to vehicles, mileage drops and a lack of fuel testing reports carried out by government agencies such as SIAM and ARAI in the public domain.

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Outside of ethanol, the use of isobutanol in diesel fuels has also been under consideration for a while. The latest draft for the upcoming CAFE Norms 2027 included the addition of a ‘Carbon Neutrality Factor’ for blended diesel fuels for calculations, though no valuations were provided. As per previous reports, the government is currently targeting blending 15 per cent isobutanol with diesel in the coming years, though as of now a time frame for the move is unknown.

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Commenting on the isobutanol blending, Gopi said that diesel offered at pumps across the country currently did not feature any isobutanol blending.

With inputs from PTI

Representational images