Types of biofuels
- Ethanol is made from sugar crops such as sugar beets and sugar cane, and starches such as corn. These crops are fermented to produce ethanol, which is combined with traditional fuel sources such a gasoline to create E10, or E15 (with the 10 and 15 indicating the percentage of ethanol present) gasoline blends.
- Biodiesel is made from natural oils taken from oil palm, algae or soybeans. These oils can be burned on their own or combined with petroleum to make biodiesel.
- Wood and other wood byproducts can be converted into liquids such as methanol, ethanol, or woodgas. In its solid state, wood or chipped waste biomass, can also be burned.
The chart to the left shows U.S. monthly biodiesel production in 2013. Production was highest in December, where 135.1 million gallons biodiesel were produced. In total 777.6 million gallons of biodiesel were produced in 2013 in the United States. This surpassed biodiesel production in both 2011 and 2012. In 2013 there were 115 biodiesel plants across the U.S., with production concentrated in the Midwest. These plants have the capacity to produce 2.2 billion gallons of biodiesel per year.
First generation biofuels
The first generation of biofuels used traditional foodstuffs such as corn and soybeans to generate liquid fuel. Eventually these methods were met with some criticism. First critics argued that the quotas created by Congress to increase the use of biofuels misallocated foodstuffs, removing food from dinner tables and pouring it into engines, while increasing the price of food. This argument is known as the food versus fuel debate. Biofuels were also seen as a way to decrease carbon emissions, however some research has suggested that if researchers consider the carbon emitted during the entire lifetime of the crops used in biofuels, then biofuels have a larger carbon footprint than traditional gasoline. Additionally, drivers who put gasoline with ethanol into cars that aren't built to use the blend can void their car warranties and damage their engines. The debate over these criticisms continues to this day, and as technology improves it is expected that these potential problems can be better addressed.
Second generation biofuels
Research is underway to expand the types of biomass that can be used to create biofuels. The National Renewable Energy Laboratory (NREL) is just one of many research institutions experimenting with ways to transform algae into transportation fuel. These second generation biofuels have three challenges to overcome according to the The Economist. First, they must be created from food waste, or biomass that has no nutritional value, thus avoiding the food versus food debate. It is more difficult to break down food waste products, such as corn stalks, grass and trees, into the simple sugars needed for fuel, which makes using food waste a ttechnological barrier for researchers. Second, producers will have to alter their fuels to work in existing vehicles. Some of the pushback against biofuels has occurred because ethanol can damage car engines and void car warranties. Third, biofuels need to be affordable so that they are attractive option for consumers.
- U.S. Energy Information Administration, “Glossary, B” accessed January 29, 2014
- New York Department of Environmental Conservation, "How Biofuel is Made," accessed April 28, 2014
- The Economist, "What happened to biofuels," September 7, 2013
- The Washington Times, "Running on empty: EPA slashes biofuel goals because of ethanol shortage," April 23, 2014
- U.S. Department of Energy, "Ethanol," accessed April 28, 2014
- U.S. Energy Information Administration, "Monthly Biodiesel Production Report," February 27, 2014
- Forbes, "Despite Evidence, Food Vs. Fuel Fight Continues," July 11, 2013
- Popular Mechanics, "Can E15 Gasoline Really Damage Your Engine?," December 21, 2010
- USA Today, "AAA warns E15 gasoline could cause car damage," November 30, 2012
- National Center for Biotechnology Information, "The Carbon Footprint of Biofuels: Can We Shrink It Down to Size in Time?," June 2008
- National Renewable Energy Laboratory, "Biofuels Basics," July 25, 2014