Ethanol fuel is a renewable resource, produces fewer emissions than fossil fuels, and can be produced anywhere. While the energy ratio of ethanol is less efficient than gasoline, requiring more energy to produce each gallon, advancements in technology continue to improve ethanol's performance.
Ethanol fuel can be created from a wide variety of plant material. Corn is the primary ethanol crop in America, although sugarcane and switchgrass ethanol may offer better energy returns. One major concern about corn ethanol is that increased use of the fuel could put pressure on supplies of the grain worldwide, increasing food costs and potentially leading to shortages.
The major environmental benefit of ethanol fuel comes from the fact that the carbon dioxide produced by burning it is offset by the carbon dioxide the growing plants filter out of the atmosphere. This is in contrast to fossil fuels, which release carbon sequestered underground millions of years ago without any corresponding carbon dioxide removal.
Ethanol is a common additive to gasoline, with blends of 10, 15 and 85 percent ethanol in use as of 2015. E10 gasoline is approved for use in all engines, while E15 may cause problems in cars built before 2000. E85 requires a specially-designed engine, and it is incompatible with the other fuel types.