Ethanol is an alcohol-based fuel made by fermenting and distilling starch crops, such as corn.
- E10 (also called “gasohol”) is a blend of 10% ethanol and 90% gasoline. All manufacturers approve the use of blends of 10% ethanol or less in their gasoline vehicles.
- E85, a blend of 85% ethanol and 15% gasoline, can be used in flexible fuel vehicles (FFVs), which are specially designed to run on gasoline, E85, or any mixture of the two. FFVs operating on E85 experience a 20-30% drop in miles per gallon due to ethanol’s lower energy content.
Diesel engines are more powerful and 30-35% more fuel-efficient than gasoline engines.
- New engine designs have made them quieter and smoother.
- New “clean” ultra-low sulfur diesel reduces emissions of particulates and smog-forming nitrogen oxides (NOx).
Natural gas, a fossil fuel comprised mostly of methane, is one of the cleanest burning alternative fuels. It can be used in the form of compressed natural gas (CNG) or liquefied natural gas (LNG) to fuel cars and trucks.
- Dedicated natural gas vehicles are designed to run on natural gas only.
- Dual-fuel or bi-fuel vehicles can also run on gasoline or diesel.
- Natural gas is stored in high-pressure fuel tanks, so dual-fuel vehicles require two separate fueling systems, which take up passenger/cargo space.
Propane or liquefied petroleum gas (LPG) is a clean-burning fossil fuel that can be used to power internal combustion engines.
- LPG-fueled vehicles produce fewer toxic and smog-forming air pollutants.
- LPG is usually less expensive than gasoline, and most LPG used in U.S. comes from domestic sources.
Biodiesel is a form of diesel fuel manufactured from vegetable oils, animal fats, or recycled restaurant greases. It is safe, biodegradable, and produces less air pollutants than petroleum-based diesel.
- Biodiesel can be used in its pure form (B100) or blended with petroleum diesel. Common blends include B2 (2% biodiesel), B5, and B20.
- B2 and B5 can be used safely in most diesel engines.
- B100 is generally not suitable for use in low temperatures.
- Biodiesel can be used in most diesel engines, especially newer ones.
- Biodiesel is safer to handle compared to petroleum diesel.
- You should never fuel your vehicle with clean or used grease or vegetable oil that has not been converted to biodiesel. It will damage your engine.