The government is rapidly promoting ethanol-blended fuels across India, including E85 and E100 variants.
In cities like Delhi, E85 fuel has already launched at ₹82.12 per litre.
This price appears nearly ₹20 lower than regular petrol, creating an impression of major savings.
However, real-world usage shows a far more complex cost calculation.
Lower Price Per Litre Does Not Mean Lower Driving Cost
At first glance, cheaper ethanol fuel seems like a direct benefit for drivers.
Yet, fuel pricing alone does not determine total running expense.
Instead, the actual impact depends on mileage and energy output per litre.
To understand this, energy density becomes the key factor in comparison.
Scientifically, ethanol carries 30 to 35 percent less energy than petrol.
Therefore, one litre of ethanol produces significantly less engine power.
Mileage Drops Due to Lower Energy Output
Because of reduced energy density, engines consume more ethanol to maintain performance. As a result, flex-fuel vehicles require higher fuel volume for equal output.
Consequently, mileage drops by 20 to 30 percent in ethanol-based driving. For example, a car giving 18 km per litre on petrol costs about ₹5.67 per kilometre.
This calculation uses petrol priced at ₹102 per litre in Delhi. However, with E85 priced at ₹82.12, mileage drops to around 13.5 km per litre.
Real Cost per Kilometre Calculation Changes the Picture
When recalculated, E85 increases the running cost instead of reducing it. The same vehicle ends up costing about ₹6.08 per kilometre on ethanol. Thus, cheaper fuel at the pump does not guarantee savings on the road.
When Ethanol Actually Becomes Beneficial
Brazil offers a global reference point for ethanol usage efficiency. There, drivers follow a simple “70% rule” for cost advantage. According to this rule, ethanol must cost 70% or less than petrol.
Currently in India, E85 stands at nearly 80 percent of petrol pricing. Therefore, no major financial advantage appears under present conditions.
However, future price shifts in crude oil may change this equation significantly.
