Diesel-isobutanol blending mandate likely this year: What it means and how it impacts India's energy security—explained
According to Road Transport and Highways (MoRTH) Secretary V Umashankar, this initiative could have a greater effect on the country’s energy security than ethanol blending in petrol, as diesel consumption is almost double that of petrol.Speaking on Friday, MoRTH Secretary V Umashankar said the proposed measure would support efforts to decarbonise highways and transportation while decreasing dependence on conventional fossil fuels.Addressing the 'CII Multimodal Transportation and Logistics Summit', Umashankar further said that the highways ministry may soon bring a draft notification on truck-trailer interchangeability to build an ecosystem that requires battery swapping and charging for electric heavy-duty commercial vehicles.“Blending of diesel has been looked into with great seriousness. Bharat Petroleum is already undertaking strategic research for isobutanol blending with diesel. And the results are very encouraging,” PTI quoted the official as saying.“It is quite likely that the blending mandate will start coming in somewhere later this year,” he said.Umashankar said that since diesel consumption is almost twice that of petrol, the impact of diesel blending on India's energy security will be far greater than even petrol blending.The transport secretary said the blending programme, which has taken off in the last 10-12 years, is further being expanded, and the ministry has issued a draft notification for E85 (a blend of 85 per cent ethanol with petrol) and E100 (which would allow vehicles to run on nearly pure ethanol) vehicle manufacturing requirements."There have been some concerns about blending at the lower level (E20), but here it is a little different because the vehicle is manufactured differently. It will have a separate (fuel) dispenser also at the petrol pumps for dispensing E85 or E100 fuel, unlike normally blended petrol, which is done through a common dispenser," Umashankar said.What is Isobutanol? What you need to knowIsobutanol is a four-carbon alcohol (C₄H₁₀O), making it a higher alcohol compared to ethanol, which contains only two carbon atoms. It can be produced from renewable sources such as biomass, agricultural waste, or through processes linked to ethanol or sugarcane production.Apart from its use as an industrial solvent in products like paints and coatings, it is increasingly being explored as a potential biofuel for transportation.It is considered suitable for blending with diesel because ethanol faces several limitations when mixed with diesel, including phase separation, a low flash point that raises safety concerns, corrosion issues, and poor compatibility with engines.Isobutanol helps overcome many of these challenges. It blends more uniformly with diesel without the need for additional additives, has a higher energy content closer to diesel, offers a higher flash point that makes it safer and less volatile, and is less corrosive, making it more compatible with existing engines and fuel infrastructure.Diesel is a chemically different fuel from petrol, and blending additives into it requires careful consideration of engine tolerance and compatibility.While petrol engines have been operating on ethanol-blended fuel for years with relatively few issues, diesel engines, particularly older models, can be much more sensitive to changes in fuel composition.This is mainly because diesel engines rely on compression ignition, unlike petrol engines, which use spark ignition. As a result, the chemical properties of diesel fuel have a more direct impact on combustion timing, efficiency, and overall engine performance.Research currently being carried out at Bharat Petroleum is aimed at ensuring that isobutanol–diesel blends satisfy the combustion behaviour and lubricity standards required by existing diesel engines used in vehicles across Indian roads, according to a Hindustan Times report.About the AuthorMausa
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