Context:
India had set a target in 2021 to achieve 20% ethanol blending in petrol (E20) by 2025. Vehicles modified for E20 compatibility started rolling out from April 2025. While aimed at reducing carbon emissions and oil import dependency, the move has raised concerns among vehicle owners about mileage, corrosion, and higher maintenance costs.
What is Ethanol?
- A biofuel made from biomass (sugarcane molasses, broken rice, maize, lignocellulosic materials).
- Acts as an oxygenate when blended with petrol → enables better combustion.
Production Process
- From molasses (C-heavy & B-heavy) via fermentation using enzymes (invertase, zymase).
- From food grains & lignocellulosic material after conversion into fermentable sugars.
Fuel Properties
- Calorific Value (CV): Lower than petrol → theoretically reduces mileage.
- Octane Number: Higher than petrol → reduces engine knocking.
- Hygroscopic Nature: Ethanol attracts water → risk of corrosion in tanks, pipes, and injectors.
Impact on Vehicles
- Older Vehicles (pre-BS-VI, mostly carbureted): Cannot adapt easily; risk of corrosion and clogging.
- Modern Vehicles (BS-IV & BS-VI, ECU-equipped): Can recalibrate spark timing & combustion; less affected.
- Government’s Position: Part replacement (rubber/gaskets) is inexpensive and needed only once in a vehicle’s lifetime.
Global Comparison – Brazil’s Ethanol Story
- Brazil uses E27 petrol after decades of phased policy (since 1975).
- Government built strong production capacity, subsidies, and flex-fuel engine adoption.
- Indian scenario differs: Most pre-2020 vehicles not designed for flex-fuel.
