The Ministry of Petroleum and Natural Gas recently addressed public concerns about the impact of 20% ethanol blending (E20) in petrol on vehicle efficiency.
The Ministry, in an X.com post, confirmed that ethanol has a lower energy density than petrol and may cause a marginal decrease in mileage.
Specifically, four-wheelers designed for E10 and calibrated for E20 may see a 1–2% drop in mileage, while other vehicles may experience a reduction of 3–6%.
Dismissing claims that E20 causes a drastic drop in fuel efficiency, the Ministry said such allegations are factually incorrect. It explained that improved engine tuning and use of E20-compatible materials can minimise efficiency loss, and major automakers have already adopted these upgrades.
The Society of Indian Automobile Manufacturers (SIAM) noted that E20-compliant vehicles with upgraded components began rolling out in April 2023.
Scientific studies cited by the Ministry, including those from the Automotive Research Association of India (ARAI), Indian Institute of Petroleum (IIP), and Indian Oil Corporation (R&D), showed no significant impact on vehicle performance, power, or fuel consumption when using E20.
Testing covered both carbureted and fuel-injected vehicles up to 100,000 km, with no major differences observed in performance, drivability, or wear-and-tear. E20 also passed hot and cold start tests without engine damage.
Regarding material corrosion, the Ministry stated that safety standards, including corrosion inhibitors and compatible materials, are defined by BIS specifications and Automotive Industry Standards.
For older vehicles, replacement of rubber parts or gaskets may be advised after 20,000 to 30,000 km of use. These replacements are minor, low-cost, and can be carried out during routine servicing.
On environmental impact, the Ministry highlighted that ethanol replaces petrol, reducing CO2 emissions. Ethanol is now produced not only from sugarcane but also from surplus rice, maize, damaged food grains, and agricultural residues.
A NITI Aayog study found that greenhouse gas emissions from sugarcane-based ethanol are 65% lower than petrol, and 50% lower for maize-based ethanol.
The Ministry also said ethanol’s higher octane rating (~108.5) compared to petrol (~84.4) improves ride quality and performance in high-compression engines. Ethanol’s higher heat of vaporisation lowers intake temperatures, increasing air-fuel density and volumetric efficiency.
E20 blending, the Ministry added, boosts India’s energy security by reducing crude oil imports. Since 2014–15, over ₹1.4 lakh crore has been saved in foreign exchange. It also supports rural income, with over ₹1.2 lakh crore paid to farmers through ethanol procurement. Additionally, E20 blending has helped reduce CO2 emissions by 700 lakh tonnes.
