Biofuels
Biofuels are liquid transportation fuels made from renewable energy sources that burn cleaner than petroleum and reduce greenhouse gas emissions. Currently, the term biofuels primarily refers to two distinct fuels, ethanol and biodiesel, although other fuels are being developed.
Ethanol is a fuel made from sugar, starch or other carbohydrates that can be blended with regular gasoline. Any vehicle can run on an ethanol blend up to 10% (10% ethanol/90% gasoline). Flex Fuel Vehicles (FFVs) which are specifically designed to run on ethanol can be run on E85 (a blend of 85% ethanol and 15% gasoline).
Biodiesel is a fuel made from soybean or rapeseed oils, animal fats, waste vegetable oils or microalgae oils. It can be blended with diesel fuel or used alone in compression-ignition (diesel) engines with little or no modifications.
Advances are being made in biofuel technology, including development of cellulosic ethanol. Cellulosic ethanol is produced from plant matter or waste and has a very high life-cycle net energy balance. Cellulosic ethanol can be produced from corn stover, switchgrass, and plant waste from industrial processes such as sawdust and paper pulp.
Much innovation has gone in to developing energy crops such as switchgrass. Native to the Midwestern plains and the southeast, switchgrass is a perennial tall-grass that can grow anywhere from 5-12 feet tall. It is tolerant of poor soils, and sequesters carbon in its roots and the soil it is planted in, actually improving the quality of the soil.
Feedstocks
Ethanol
- Corn - Currently the primary feedstock for ethanol production in the US, corn can be milled either in dry-mill or wet-mill processes.
- Sugar - The primary feedstock for ethanol production in tropical areas such as Brazil.
- Cellulose
- Switchgrass
- Soybean Oil
- Canola Oil
- Waste
- Grease
- Animal Fats
- Microalgae Oils
- Crude Corn Oil