Ethanol-Blended Petrol Sparks Car Performance Worries

Post by : Amit

Ethanol-Blended Petrol Causing Stir Over Car Performance

India’s ambitious ethanol blending program is raising eyebrows, not just for its environmental promise, but for the growing list of drivers reporting fuel efficiency drops, misfiring engines, and increased maintenance costs. As the country moves steadily toward achieving E20 fuel nationwide—20% ethanol blended with 80% petrol—questions are now surfacing about whether this cleaner-burning fuel is compatible with the existing fleet of internal combustion engine (ICE) vehicles on Indian roads.

A Push for Greener Fuel, but at What Cost?

In 2021, the Indian government fast-tracked its ethanol blending target by five years—from 2030 to 2025. The goal was clear: reduce dependence on oil imports, cut carbon emissions, and promote domestic biofuel production. In theory, this approach not only supports sugarcane and grain farmers but also curbs tailpipe emissions. But as E20 fuel becomes increasingly common at petrol pumps, the real-world impact on consumer vehicles is beginning to show—and not all of it is positive.

Several motorists across urban hubs like Delhi, Mumbai, Pune, and Bengaluru are complaining of deteriorating fuel efficiency, poor engine idling, and in some cases, irreversible engine damage. “My car used to give 18 km/litre. With this new petrol, I’m struggling to get even 15,” says Rohit Khurana, a Pune-based IT professional who drives a compact sedan.

Ethanol's Double-Edged Chemistry

At the heart of the debate lies the chemical nature of ethanol itself. Ethanol is hygroscopic—it absorbs moisture from the air. This can lead to water separation inside fuel tanks, particularly in high humidity regions, causing corrosion and microbial growth in the fuel lines. Over time, this not only erodes fuel system components but also interferes with combustion, resulting in knocking or misfiring.

Secondly, ethanol has lower energy density than petrol. A litre of ethanol produces about 30% less energy than a litre of gasoline. The higher the ethanol content in the blend, the lower the energy output per litre of fuel. This directly translates to fewer kilometers per litre, something motorists are now beginning to notice.

“Ethanol blends may be environmentally friendly, but they’re not always engine-friendly—especially in vehicles that were not built for it,” says Dr. Ramesh Mahindra, an automotive fuel systems researcher at the Indian Institute of Science (IISc).

Automakers Acknowledge Challenges

Major OEMs have acknowledged these concerns and are now actively testing and calibrating engines to accommodate E20. Maruti Suzuki, Hyundai, Tata Motors, and Honda have all announced their intention to roll out E20-compatible models by 2025. However, a vast majority of the vehicles currently on the road—especially two-wheelers and entry-level passenger cars—were not designed for ethanol-heavy blends.

Rajesh Menon, Director General of SIAM (Society of Indian Automobile Manufacturers), admitted the transition will come with growing pains. “E10 was a good start. E20 is more challenging. Engine durability, fuel lines, rubber seals—all have to be revalidated or replaced. This takes time and money,” he said.

Several auto component suppliers are also under pressure to redesign parts such as fuel pumps, hoses, and injectors that can withstand ethanol’s corrosive tendencies. “We are seeing increased demand for ethanol-resistant elastomers and coatings,” confirmed a spokesperson from Anand Group, a key Tier-1 supplier.

Service Centres Seeing Spike in Complaints

Workshops and service stations are reporting an uptick in fuel-related issues, particularly in vehicles older than five years. “We’ve seen more clogged fuel filters and corroded injector tips in the last six months than we did the whole of last year,” says Anil Sharma, who runs a multi-brand car service centre in Delhi’s Okhla region. “In 70% of the cases, it’s linked to ethanol-blended petrol.”

He explains that most of these cars are not equipped with sensors or ECUs programmed for E20 compatibility. As a result, air-fuel mixtures become inefficient, combustion gets delayed, and performance suffers.

Some two-wheeler service technicians in Maharashtra and Tamil Nadu are even advising customers to mix branded fuel additives to counter ethanol’s corrosive impact—an informal practice that brings its own risks.

Government Response: Blending Mandate Will Stay

Despite the growing criticism, the Indian government remains firm in its commitment to E20. The Ministry of Petroleum and Natural Gas (MoPNG) insists the shift is crucial for national energy security. “India imports over 85% of its crude oil. Ethanol blending can reduce this significantly while offering economic opportunities for farmers,” stated Hardeep Singh Puri, Minister for Petroleum and Natural Gas, during a recent address.

To address user complaints, the Bureau of Indian Standards (BIS) is working with automotive testing agencies like ARAI and ICAT to issue updated fuel compatibility norms for legacy vehicles. Fuel retailers like Indian Oil, Bharat Petroleum, and HPCL have also been directed to prominently display ethanol percentages at their pumps to prevent misfuelling.

Still, experts warn that without a massive public awareness campaign, confusion and misinformation may worsen.

What Can Motorists Do?

Industry veterans recommend that users check their vehicle manual or manufacturer website to verify ethanol compatibility. “E10 has been around for years and most vehicles from 2010 onwards can handle it. But E20 is another ballgame,” says Pratik Dey, a fuel systems engineer at Bosch India.

He suggests using full tanks (to reduce condensation), frequent oil changes, and ethanol-friendly fuel additives for older vehicles. For fleet operators and logistics companies, scheduled fuel line inspections and early adoption of E20-ready engines may be a safer bet than waiting for mass-market recalibrations.

India’s Biofuel Bet

India is not alone in pushing ethanol-blended fuels. The U.S. has long operated on E10 and E15 blends, and Brazil famously runs most of its cars on E25 and even E100, with dedicated flex-fuel engines. But unlike Brazil, India’s flex-fuel penetration remains negligible. That’s a critical gap, says Prof. Abhay Mehta, a fuel policy analyst with The Energy and Resources Institute (TERI).

“We’ve put the cart before the horse. Introducing E20 without a mass rollout of E20-compliant vehicles and flex-fuel engines could backfire,” Mehta said.

Adding to the concern is the sustainability of ethanol production itself. The majority of India’s ethanol comes from sugarcane—a water-intensive crop—raising questions about long-term ecological viability. Although the government has plans to diversify feedstocks to grains and bio-waste, implementation is slow.

Will India See a Shift Toward Flex-Fuel Engines?

Japanese auto giant Toyota has already launched pilot projects for flex-fuel vehicles in India, and Honda is reportedly conducting feasibility studies. The success of such initiatives could pave the way for more robust ethanol adoption without compromising engine health.

Until then, automakers, refiners, and consumers are navigating a transition fraught with mechanical, economic, and environmental trade-offs.

Course Correction Needed?

India’s green fuel transition, particularly through ethanol blending, is undoubtedly a step in the right direction when viewed through the lens of energy independence and carbon emissions. But it’s becoming increasingly evident that more planning is needed to avoid burdening the average consumer.

The road to sustainability must also be a road of reliability—and that includes making sure that what goes into the tank doesn’t damage what’s under the hood. With better engine calibration, clearer messaging, and thoughtful retrofitting policies, India can still ensure that its ethanol bet pays off—not just for the planet, but for the people too.

Ethanol, Petrol