Maruti Suzuki’s advertising catchline “kitna deti hai” and “petrol khatam hi nahin hunda” were instant hits, distilling the Indian motorist’s obsession with fuel efficiency into a pithy catchline. The country’s largest carmaker was hardly breaking new ground: decades earlier, Hero Honda had struck a similar chord with its “fill it, shut it, forget it” campaign, highlighting the efficiency of its four-stroke engines and buttressing the notion that thrift at the pump was the ultimate measure of automotive value.That sentiment has proved remarkably resilient, even as India’s car market has upshifted to premium offerings with buyers looking to combine mobility with aspirational pursuits. Despite that, the calculus of mileage still remains a key hard sell and the promise of frugality continues to endure in a nation where mobility is expanding, but growth in disposable incomes remain patchy.Ahead of scheduleThat is where the government’s new ethanol blending programme is playing spoilsport. Last year, India fully transitioned to 20% ethanol blending in petrol — five years ahead of the original target of 2030. E20 fuel — 80% petrol and 20% ethanol — is now the standard petrol variant available nationwide.So, essentially, within three years, the average ethanol blending level in petrol doubled from the earlier 10% to 20% (this was originally slated to happen over eight years). For older vehicles and those certified for E10 petrol — 90 parts petrol and 10 parts ethanol — this transition came about rather quickly, without sufficient warnings of the consumer-end pitfalls. The experience left motorists, especially those owning older cars and two-wheelers, feeling somewhat short-changed.Now, there are three problems with using a higher ethanol blend in petrol for engines not designed for these blends:One, there is a substantial drop in fuel economy depending on when the car was manufactured.Second, filling E20 fuel in internal combustion engine (ICE) vehicles, especially older ones, could see some damage to parts owing to factors like corrosion, given that ethanol has a higher water content.Story continues below this adThird, vehicle owners in India currently do not have an option to choose different fuels at the petrol pump, unlike their counterparts in Brazil where customers are presented with a choice of fuels with differential pricing and under Brazilian law, there has to be a pricing discount for higher ethanol blends.Also read | Centre rejects claim that India’s E20 fuel push is just an ‘experiment’Indian vehicle owners did not receive blended fuel at a cheaper cost. But this comes at the cost of lower mileage and worries about damage in older vehicles — a cost that is forced down the throat of the motorists. Also, regular ICE cars running on higher ethanol blends, alongside the drop in mileage, are harder to start on winter mornings because ethanol burns at a higher temperature than petrol.While a fuel with 10 per cent ethanol (E10) made little difference to a car’s performance, anything above that is said to impact operations. And the worsening of the performance does not exactly progress in a linear fashion as the blending levels keep increasing. The government has a plan to go further up from E20, and that is worrying customers given their experience with the E10 to E20 transition.The chemistry issueSo, what really is the core problem? Chemically, the proposition of ethanol blending doesn’t appear to be so bad. Ethanol is what is called a carbon chain two, that is C2H5OH, whereas petrol being used at the pumps is somewhere much higher in the range in terms of the carbon content — from between C8 and C12. So, for every molecule of petrol burnt versus every molecule of ethanol burnt, the carbon dioxide levels will be necessarily lesser as the ethanol blend increases.Story continues below this adSecondly, ethanol also has a very high octane number, so it can result in a cleaner burn inside an internal combustion engine than pure petrol. It is a fact that ethanol’s exceptionally high-octane number (approximately 108 RON, or Research Octane Number) has made it a preferred fuel component for high-performance ICEs.Ethanol and ethanol-based fuels have historically been used in sports cars because of their superior anti-knock characteristics, better power potential and cooling effect stemming from their high latent heat of vaporisation. Most turbocharged and high-compression engines worldwide do rely on ethanol blends to realise higher performance, while simultaneously reducing emissions.Multiple carmakers in India told The Indian Express that given the higher RON, they can now begin working on engines with higher compression ratios to extract the maximum mileage out of higher ethanol blends. But that is all for the future. On its part, the government continues to maintain that the roll-out of higher ethanol-petrol blends will only be done after proper testing and consultations.Also, it is the United Progressive Alliance government (2004-14) that had originally notified in its first National Policy on Biofuels in 2009 an indicative target of 20% ethanol blending in petrol by 2017, which got pushed back for a number of reasons. Also, a scientific study on “Assessing the effect of E10 on the existing vehicles”, was undertaken in the year 2009-10, by Indian Oil, Pune-based Automotive Research Association of India (ARAI), and industry lobby group SIAM, which suggested that the shift was operationally feasible.Story continues below this adBut ethanol has lower calorific value than petrol, which means something like 30% less mileage. The mileage issue continues to be a headache for motorists, especially as the government progresses to blends higher than E20.Then there is the concern over vehicular part damage in older cars owing to factors like corrosion, given that ethanol has a higher water content, but much that seems to be overblown. A top carmaker had initially planned to launch a kit in the market for older cars to effectively refurbish vulnerable rubber and plastic parts and prevent material damage, but that plan now, at least for the record, seems to have been put off and is “only being done for internal testing and R&D purposes”.There are, however, multiple claims by vehicle owners of fuel pump issues and other problems. On its part, the government contends that most clips doing the rounds claiming engine damage “appear to rely on unverified claims, selective presentation of facts and click-bait headlines designed primarily to generate online viewership”.Material damageWhile the E20 introduction was clearly rushed, given that the deadline was actually advanced by this administration, the government did depute the ARAI to conduct a study on the impact of E20 fuel on the materials used in fuel-system components. An evaluation of 8 metals, 6 elastomers, and 4 plastics used in various fuel-system components was conducted through “systematic exercise of laboratory immersion” and the study was conducted with E20 as test fuel and commercial petrol (Bharat Stage IV emission standards) as a baseline fuel (E10) for comparative assessment.Story continues below this adImpact of E20 on metals was evaluated through calculation of corrosion rates in mm/year based on data obtained for change in mass post-immersion in fuels, an official said. Also, impact of elastomers and plastics was evaluated through observed changes in properties like mass, volume, tensile strength, elongation, impact strength, and hardness.The ARAI study concluded that the impact of E20 on metals tested “was found to be insignificant based on the corrosion rates”, with polychloroprene and fluoroelastomer found to perform “similar or better in most of the properties with E20” and the impact of E20 on “tensile strength and volume change properties” was found to be more than commercial petrol.Now, ARAI is a government body, and some of its predictions, including the fuel efficiency ratings that it offers “under standard test conditions”, are vastly different in real life driving conditions.Also read | Does E20 petrol reduce mileage of your car, bike? Centre answersAs far as vehicle degradation goes, manufacturers, on record, say they have not encountered any major issues with the E20 transition. Privately though, they admit to this being a concern when the blending levels increase further, particularly for older cars and two-wheelers. Plus, the knock on fuel economy is absolutely real. And as fuel blends increase, this is only going to get worse.Story continues below this adThere is a plan to go up from E20 to E25. Alongside that, there is a plan to introduce E85 fuel for flex-fuel vehicles. Even in a flex fuel vehicle, which is equipped to have higher ethanol blends, it’s cheaper to run the standard E20 fuel than the proposed E85 because the difference between the price of the fuel normally and in the higher blend has to be more than the fuel efficiency loss of over 25%. In Brazil, this switch is only viable when the E85 becomes at least 30% cheaper. That choice has to be made available with a pricing differential for Indian consumers if E85 has to take off.In private, vehicle makers also confide that the impact could be higher from E20 to E25, than it was for E10 to E20. This is especially true for older engines and the ones used on two-wheelers, where high-grade aluminum or steel casts are not used for the engine block. A senior technical expert at a major automaker told The Indian Express that there are no conclusive studies into the long-term impact blended fuel can have on non-compliant vehicles, but flagged that it could definitely have an impact on the engine’s life, its various rubber parts, valves, and piston heads, among others.It is the E25 transition that has hassled automakers at the moment, since this will require additional engineering and validation work around engine calibration, fuel-system durability, corrosion resistance, and material compatibility. And homologation — the process that officially certifies a vehicle or component as compliant with regulations pertaining to safety, environment, and road-worthiness — at the end.This is just months after the government wrapped up the E20 transition. In all probability, the cost of vehicles will go up too, and the consumer will have to bear it. Not to mention the lower mileage, which a lot of customers are clearly testifying to after the E10 to E20 shift. According to sources in the government, the move towards blends higher than E20 is “not being pushed through in a hurry and there will be enough time given for vehicles and oil companies to gear up for this transition”.Story continues below this adWhy is the government pushing for blends beyond E20? The main reason is the government’s resolve to further lower India’s dependence on fuel imports and aid domestic ethanol production amid rising fuel prices due to tensions in West Asia.There’s a political angle too: the agricultural lobby, especially from Maharashtra and Uttar Pradesh, is pushing hard for ethanol blends to be hiked since farmers such as those growing sugarcane are sitting on significant overcapacity. For the oil marketing companies such as Indian Oil and Bharat Petroleum too, there are challenges, but given the fact that they are mostly state-owned, they are unlikely to protest.Also in Explained | The worries in India’s push beyond E20 fuel — and lessons it can take from BrazilNow for adapting the existing set of vehicles to E25, car makers said they would have to run fresh tests to see what impact the higher ethanol blend will have on the older vehicles on the roads. As far as the new vehicles that will be sold, the manufacturers will have to recalibrate and redo the certification and homologation for emissions, because all the vehicles that are selling now have been tested, certified, and homologated for emissions using E20. Homologation has to be done with the new E25 fuel, as it was done with E20 earlier. Then, of course, there is the looming question: the impact on mileage. The problem here is that the brunt of the drop in fuel efficiency from the E10 to E20 transition was borne by the motorist.“In case of this new transition too, the consumer will likely end up bearing the brunt of any drop in fuel efficiency. For older vehicles, there is the added question over vehicle damage due to the high ethanol mix. That too is left to the consumer,” a representative of an auto manufacturing association said.The Brazilian templateStory continues below this adA decades-long push for blended fuel in Brazil may have a template for how India could move forward. Brazil’s widespread use of flex-fuel vehicles is a story of strong government mandates, visible price incentives for consumers, clear guidance to carmakers, and robust consumer education that helped mainstream higher ethanol blends like E20 and above. The real question is whether India can learn from these strategies to boost E20 acceptance and effectiveness.Over the past five decades, Brazil has worked to create a viable alternative to petrol by using more sugarcane-based fuels in the mix. Brazil’s ethanol programme, which kicked-off in the 1970s, was in response to the uncertainties of the oil market.NewsletterFollow our daily newsletter so you never miss anything important. On Wednesday, we answer readers' questions.SubscribeAt nearly every petrol pump in Brazil now, people have an option to either choose between blended petrol, which typically includes 27-35% ethanol, and E100, which is pure hydrous ethanol.Alongside that, Brazilians also got carmakers to usher in flex-fuel cars, thereby enabling the consumer to fill up with whichever option is cheaper at the pump on a particular day — often E100 is cheaper by 25-35% compared with lower blended petrol.The flex-fuel cars were a big hit with Brazilian consumers, largely because government price support made the blended fuel cheaper than petrol at the pump. Ethanol also improves acceleration, an advantage in a country where Formula One racing is a national obsession. By the late 1980s, nine out of every 10 new cars sold in Brazil were capable of running on ethanol alone.When Brazilians drive to a fuel pump to tank up, they get a choice of fuel mixes at different price points. In India, that is far from the case.