Ethanol-blended gasoline is a motor fuel composed of petroleum-based gasoline mixed with ethanol, a renewable bio-alcohol produced from sugarcane, corn, molasses, grains, or cellulosic biomass. The blending ratio is denoted by “E” followed by the ethanol percentage.
E10 contains 10% ethanol, E15 contains 15% ethanol, and E85 contains up to 85% ethanol for flex-fuel vehicles. These blends are adopted globally to reduce emissions, improve octane performance, and support renewable energy mandates.
Types of Ethanol Blends & Usage
E10 (Gasohol)
Most widely used globally
Compatible with almost all modern petrol vehicles
No engine modification required
E15
Higher ethanol content than E10
Approved for newer petrol vehicles
Not recommended for older engines or small equipment
E85
High-ethanol fuel for flex-fuel vehicles
Requires ethanol-resistant fuel systems
Maximum emission reduction with lower fuel economy
Key Fuel Characteristics
Cleaner combustion due to oxygenated fuel structure
Reduced CO, HC, and particulate emissions
Higher octane rating (ethanol: 108–113 RON)
Reduced dependence on toxic aromatic octane boosters
Energy Density Comparison
| Property | Ethanol | Gasoline |
|---|---|---|
| Octane Number | 108–113 | 87–98 |
| Energy Content | ~21 MJ/L | ~32 MJ/L |
| Oxygen Content | ~35% | 0% |
| Flash Point | 13°C | −43°C |
Engine & Vehicle Compatibility
E10: Safe for most petrol engines and catalytic converters
E15: Suitable for newer vehicles, not recommended for motorcycles or small engines
E85: Requires flex-fuel vehicles with ethanol-compatible components
Environmental Impact
Lower tailpipe emissions
Reduced lifecycle greenhouse gas emissions (20–70%)
Improved urban air quality
Supports national clean-fuel policies
Storage & Handling Considerations
Hygroscopic nature requires moisture-free tanks
Risk of phase separation if water contamination occurs
Higher blends require compatible materials and coatings
Advantages & Limitations
Advantages:
Renewable energy source
Higher octane performance
Reduced emissions
Supports energy security
Limitations:
Lower fuel economy at higher blends
Material compatibility challenges at E85
Sensitive to moisture during storage
Common Applications
Passenger vehicles
Commercial fleets
Government and public transport vehicles
Agriculture and rural equipment
Ethanol-enabled performance and racing fuels