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Pramod Joshi has been driving a Volkswagen Vento in Pune for the past six months, and the average mileage has never been below 8 kilometres per litre. “Since I refilled with E20 petrol last week, the mileage has gone down to 6.3 kilometres per litre,” Joshi, who runs a performance marketing agency, said in a video he posted on X recently. “Mileage in my Honda Elevate is down by 20% in the past 18 months,” Ajay Kumar, another X-user, wrote. He also suspected that E20 – petrol blended with 20% ethanol – is the villain.
EngiNerd, another X user, writes: “My car mileage has dropped by at-least 10% with the same style of driving recently. If it's not because of E20 petrol then I'm sure the potholes on the road have increased which is eating more petrol. In any case you should return the money.”
Apart from mileage issues, the E20 petrol is a trending topic on social and traditional media with many questioning the insistence on E20 usage and not giving options.
“The impact of E20 petrol is likely to be significantly greater and more severe for Indians than a 50% tariff on Indian goods imposed by Trump,” says M Nageswara Rao, retired IPS on his X handle.
Another civil servant, Ashok Khemka took to his X handle, saying, “A clear conflict of interest when the auto industry vouches for the safety of E20 fuel. Alleged engine damage due to E20 fuel use in older cars would mean increasing sales of new vehicles. Who suffers? Who gains?”
Citizens have flooded the social media with concerns about the reduction in mileage on using E 20 fuel, worrying that the reduction in mileage around 5-7% for modern vehicles and 20% drop for older vehicles is for real but the government, which is literally enforcing E20 without giving them choices, is neither ready to take responsibility for the wear and tear or the additional burden on common man nor is it interested in bringing down the price of blended petrol.
Energy and climate expert Abhishek Jha, of UrjanovaC, a climate tech start-up, explains to DH, “The labelling on blended petrol is not being properly communicated to the consumer, even the dispensing staff do not know it well. This creates mistrust amongst the consumers. The public generally distrusts fuel quality.”
On mileage reduction, Jha adds, “Vehicles that use E0 fuel will observe a drop of 6-7 % in mileage when they go for E20 fuel. Vehicles which use E10 will see a drop of 2 to 3% when they use E20. Mileage has less to do with car parts and more with the energy available in the fuel. Ethanol has 30% lower energy per gallon than petrol. Blends have proportionally reduced energy content; like E10 (10% ethanol+90% petrol) has 30% less energy content than petrol per gallon. That is if you blend 10% of ethanol with 90% of petrol, the overall blend will have 3% less energy, that is 97%. Similarly, the energy content in the E20 blend will be equivalent to 94% of petrol energy.”
While a fierce debate rages on the nationwide roll-out of 20% ethanol blending in petrol, the government sees it as a game-changer in reducing the carbon footprint.
The Supreme Court on September 1 dismissed the PIL filed by advocate Akshay Malhotra, challenging the lack of consumer choices, proper labelling on petrol blends and a lack of proper study on its impact on the longevity of vehicles.
The government has time and again clarified its intent on the E20 rollout, a cleaner fuel that not only reduces carbon emissions but also the country’s dependence on crude oil imports. India has achieved its objective of blending 20% ethanol with petrol, five years ahead of its target.
Since 2014, ethanol blending has helped India reduce 69.8 million tonnes of carbon dioxide emissions and saved 1.36 trillion rupees ($15.5 billion; £11.5 billion) in foreign exchange. Government projections suggest, in 2025 the use of E20 could save Rs 43000 crore in foreign exchange while adding Rs 40,000 crore to farmers’ income.
A government release clarifies that the use of E-20 gives better acceleration, better ride quality and most importantly, lowered carbon emissions by approximately 30% as compared to E10 fuel. Ethanol’s higher-octane number (~108.5 compared to petrol's 84.4) makes ethanol-blended fuels a valuable alternative for higher-octane requirements that are crucial for modern high-compression engines. Vehicles tuned for E20 deliver better acceleration, which is an important factor in city driving conditions. Additionally, ethanol’s higher heat of vaporisation reduces intake manifold temperatures, increasing air-fuel mixture density and boosting volumetric efficiency.
The government has reiterated that the move from E15 to E20 represents a stronger push towards reducing dependence on traditional fossil fuels.
Earlier, the Ministry of Petroleum and Natural Gas had released an official statement on X, stating, "Ethanol, being lower in energy density than petrol, results in a marginal decrease in mileage, estimated at 1-2% for four-wheelers designed for E10 and calibrated for E20, and around 3-6% in others. This marginal drop in efficiency can be further minimised through improved engine tuning and use of E20-compatible materials, which leading automobile manufacturers have already adopted."
P K Banerjee, executive director at the Society of Indian Automobile Manufacturers, said recently that using E20 fuel in older vehicles lowers mileage but is not a safety risk. “Millions of vehicles have been running on E20 for quite some time now. Not a single vehicle breakdown or engine failure has been reported,” adding that if issues arise, warranty and insurance claims will be fully honoured by companies.
But not everybody is buying this argument. “Blending ethanol in petrol in the name of climate action is a myth," says Soumya Dutta, environmentalist and trustee of MAUSAM.
“One has to see the backwards linkages in the production of ethanol. The entire process of cultivation, harvest, transportation of raw materials and finally the conversion of molasses to ethanol generates a certain amount of carbon footprint. Its efficacy in reducing carbon emissions and enhancing sustainability remains debatable. Moreover, sugarcane, rice, and maize are all water-intensive crops. Also, as more areas are earmarked for sugarcane and grain production for ethanol, it literally means diverting farm produce towards manufacturing fuel, thus there would be strain on water resources, which are already depleting in India. Also, fossil fuels are used in the production of rice, sugarcane and others, hence carbon footprint is there. Our country cannot be compared with Brazil, which leads in ethanol production because they don’t face a water crisis, its population is one-sixth of India's, and it has three times our land. Moreover, E20 is hygroscopic, absorbs moisture from the air, which can affect the fuel system in vehicles. Also, the calorific value of petrol is 44 megajoules, whereas it is 30 megajoules for ethanol, so we are buying less energy for the same price, as the prices have not come down after E20 blending.
Dutta adds: “While producing ethanol from sugarcane, EROI (Energy Return on Investment) figure, gives about (based on different conditions), 3.5 to 5.5, which is a substantial gain of energy (extra coming from the Sun through photosynthesis). Even though there's a good energy gain, experts say the input energy is produced from coal and oil, with an efficiency of around 35-40% only. Thus, the total energy gain is reduced to around 2 (double the primary energy invested). And if ethanol is burned in a car engine, with an efficiency of 35-45% maximum efficiency, we do not gain any net energy after going through the whole process. In the case of rice-paddy, the EROI figures are very low, 1-1.5, according to different studies. That means, to produce 100 Megajoules MJ of energy, you have to invest nearly 79-90 MJ. Then there are transport, pumping, etc, losses. There is almost zero gain.”
Motorists reason that since ethanol has a lower energy density than petrol, car engines need to burn more of it to generate the same output. And this leads to reduced mileage around 5-7% for vehicles launched after 2023 as they are E20 compatible, but around 20% drop for older vehicles, and they need an upgrade in components such as fuel lines, pumps, and seals to handle higher ethanol content.
Biofuel expert and assistant professor at Integral University, Lucknow, Rahil Akhtar Usmani, says, “Ethanol is a potent solvent, so its prolonged exposure can damage the rubber-based fittings, corrode metals and loosen tank line deposits. Older vehicles are more exposed because many have rubber or cork hoses, uncoated aluminium or zinc parts, and older seals. Routine servicing and replacement with E20-compatible material can reduce risk, but not completely if the vehicle’s fuel system is not calibrated. Though the risk is not instant, over time it would ultimately wear the machine out. Other pertinent problems include hard-starts, rust deposition in tanks, clogged filters, etc. Technology-matching, directed transitions and protecting the users while pushing for cleaner fuels should have been the process, rather than one-size-fits-all mandates.”
Most experts believe the transition has to be gradual. Jha says, “E20 is better than E10 due to higher replacement of petrol leading to lower energy import, lesser GHG emissions and more money to farmers. However, its introduction has to be gradual and only after the infrastructure is ready and vehicles are E20 compliant. The US and EU have limited themselves to lower blends around E10.”
The government's blended fuel push has also raised concerns among food policy experts. Expanding the production of sugarcane, maize, and rice for ethanol means diverting farm produce into manufacturing more fuel.
Rahil says: “Diverting sugar, maize, or rice stocks can impact food prices and feed availability.”
To offset bringing more areas under sugarcane, rice and maize cultivation for the production of ethanol, experts say India should go in for 2G ethanol, produced from non-food biomass/agricultural residues, waste materials. Feedstocks include rice straws, wheat straws, sugarcane bagasse, corn cobs, husks, and forestry residues. Or one can also go in for the 3G ethanol, made from algae, advanced feedstocks that are not dependent on traditional crops or residues.
Experts also believe a phased rollout with more choices for consumers should be the right way to follow rather than abrupt disruption.
Most favour phased rollouts with clear labelling and consumer choices available, especially during transitions.
Rahil says, “Consumers should have choices rather than enforcement. The gradual replacement via the right mix of policy incentives (subsidies and tax cuts to both consumer and producer) is the key. This mirrors global practice in staged blend adoption. There should also be cohort-wise mileage and durability data in the public domain that will enable informed consumer choices.”
(The writer is an independent journalist)