Guwahati: The All Assam Engineers’ Association (AAEA) has extended cautious appreciation for the government’s push toward 20 percent ethanol blending with petrol (E20), while flagging concerns for owners of older vehicles not designed for higher ethanol content.
The response comes after the Supreme Court of India recently dismissed a public interest litigation challenging the standardization of E20 fuel across the country. The blend is now widely available and poses no difficulty for vehicles manufactured after 2022. However, AAEA warned that older vehicles, calibrated for 0–5 percent ethanol blending, may face performance issues under the new standard.
Ethanol (CH₃CH₂OH), a renewable biofuel introduced as an eco-friendly alternative to hydrocarbons, has hygroscopic properties—meaning it can absorb moisture from the air even after being mixed with petrol. Experts caution that in humid conditions or during the monsoon, loosely fitted fuel tank caps could allow moisture and vapour to seep in, forming a water layer at the tank’s base. This can cause starting troubles and jerks while driving.
To minimize risks, AAEA advised vehicle owners to keep fuel tanks relatively full, start engines regularly (avoiding prolonged storage of E20 fuel, particularly during rainy months), and ensure timely servicing.
“We support the government’s flexi-fuel policy, which aims to cut crude oil imports and lower greenhouse gas emissions. Assam already hosts over 15 ethanol projects, including Numaligarh Refinery Limited’s bamboo-based biorefinery. The policy is also financially empowering farmers without middlemen interference,” said AAEA president Er Kailash Sarma, working president Er Nava J. Thakuria, and secretary Er Inamul Hai in a joint statement.
However, the engineers’ forum emphasized the need for region-specific measures in the northeast, given its high humidity and frequent rainfall. “A dedicated awareness program for old vehicle owners is essential. At the same time, a comprehensive study on the long-term impact of E20 on all categories of vehicles must be undertaken, especially as the Centre plans higher levels of ethanol blending in the future,” the statement added.
AAEA’s Caution on Old Vehicles
Designed for Lower Blends
The All Assam Engineers’ Association (AAEA) noted that most old vehicles were calibrated for 0–5% ethanol content. Using E20 in such vehicles may cause performance issues.
Risks Due to Ethanol’s Nature
Ethanol (CH₃CH₂OH) has hygroscopic properties, meaning it absorbs moisture from the air even when mixed with petrol. In humid and rainy conditions, water can accumulate at the bottom of fuel tanks, leading to:
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Engine starting troubles
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Jerks during rides
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Long-term engine wear
Suggested Precautions
AAEA recommends:
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Keeping fuel tanks relatively full
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Running engines frequently to avoid long storage of E20
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Timely and careful servicing of vehicles
Benefits of Ethanol Blending Policy
Eco-Friendly and Farmer-Friendly
“We support the government’s flexi-fuel policy, which helps cut crude oil imports and reduce greenhouse gas emissions,” AAEA leaders said in a joint statement. Assam alone has over 15 ethanol projects, including Numaligarh Refinery Limited’s bamboo-based biorefinery. The policy also provides direct financial benefits to farmers by eliminating middlemen.
Special Concerns for Northeast India
Humidity and Rainfall Challenges
The engineers’ forum cautioned that the northeast’s climate—marked by high humidity and frequent rains—requires additional awareness measures.
