What does science say about the govt.’s ethanol blending plan? , PgII

Key Highlights:

• The Indian government aims for 20% ethanol blending in petrol (E20) by 2025 to cut emissions and reduce dependence on foreign oil.
• E20-compatible vehicles were introduced in April 2025, raising concerns about the impact on older vehicles and maintenance costs.
• Ethanol, a biofuel made from plant waste, acts as an oxygenate in petrol blends for better combustion.
• Concerns exist regarding corrosion in older vehicles due to ethanol's hygroscopic nature, potentially clogging fuel lines.

Detailed Insights:

• Ethanol production in India uses sugarcane byproducts like molasses, as well as damaged food grains.
• C-heavy molasses and B-heavy molasses are key sugarcane byproducts used in ethanol production through fermentation.
• Ethanol's lower calorific value compared to petrol theoretically reduces fuel efficiency, but the government cites other factors influencing performance.
• Ethanol's hygroscopic nature can cause water accumulation in fuel tanks, leading to corrosion and clogged fuel lines, especially in older vehicles.
• Recalibration of the engine's electronic control unit is needed for older vehicles to adapt to E20 fuel, potentially increasing costs.
• Brazil's Proálcool programme, initiated in 1975, offers a comparison, but their gradual approach and flex-fuel vehicle market differ from India's situation.
• BS-VI emission standards, implemented in April 2020, marked a shift towards vehicles with electronic control units, better suited for E20 fuel.

Scientific/Technical Concepts Involved:

• Calorific Value: The amount of energy produced by a fuel upon combustion.
• Octane Number: A measure of a fuel's resistance to engine knocking.
• Hygroscopic Nature: A substance's ability to attract and hold water molecules from the surrounding environment.
• Electronic Control Unit (ECU): A computer that controls an engine's operation by adjusting parameters like air-fuel ratio and spark timing.