Used as an oxygenate

• MTBE has historically been the primary oxygenate but has been banned in most states after it was discovered to be polluting water supplies and deemed to be carcinogenic
• Currently, 25 states have banned the use of MTBE ethanol is the only commercially viable replacement

Used as gasoline extender

• Increases the supply of fuel by creating E-10 (10% ethanol / 90% gasoline) that can be used by all cars without any modifications
• There is, already on the road, a large base of "flexible fuel" models which can use an 85% blend

Used as an octane enhancer

• Ethanol has an octane rating of 113, which is the highest performance fuel on the market (the Indianapolis 500 uses ethanol for race car fuel)
• Can be blended with lesser octane rated fuels