News about biofuels is everywhere these days. More often than not, the stories are about the controversy surrounding their contribution to the increased cost of food. You might be wondering if you're going to be forced to choose between your corn flakes and your car. So, what's the deal? Are biofuels good, bad, or somewhere in between?Did You Know? Biofuels are not new. Henry Ford originally planned to power his Model T's using ethanol, but gasoline became the fuel of choice because it was cheap, plentiful, and it could produce more energy per litre.
Biofuels are produced from biological materials such as plants. When people talk about biofuels, they are referring to bioethanol and biodiesel. Bioethanol is a replacement for gasoline, whereas biodiesel is a replacement for - you guessed it - diesel.
How are Biofuels Made?
Most bioethanol comes from crop plants. In North America, corn is the main starting material for bioethanol production. To produce ethanol from corn, starch, a complex polysaccharide, must be broken down into simple sugars like dextrose and glucose. These sugars are then converted to ethanol by a process called fermentation.
Did You Know? Polysaccharides are large molecules that consist of many sugars linked together. During fermentation, yeast converts sugars to ethanol and carbon dioxide.
Biodiesel is made from vegetable oils or animal fats. Soybean oil or recycled cooking oils are the main starting materials in North America. A reaction called transesterification is responsible for the conversion of plant oils to biodiesel. Transesterification is the reaction of an alcohol with oil or fat to produce fatty acid alkyl esters, otherwise known as biodiesel.
Are Biofuels Good or Bad?
Well, neither. There are clear advantages to using biofuels. They are renewable resources, burn cleaner than gasoline and diesel, and can reduce greenhouse gas emissions. But they're not perfect.
Since 2000, more and more of the North American corn crop has been diverted to fuel production. In the year 2007, ~20% of the corn crop was used for fuel compared with 5% or less before 2000. This has been a major factor in driving up the price of corn, which ultimately results in higher food prices.
As if that weren't bad enough, increased land clearance to grow more biofuel crops results in more atmospheric carbon dioxide and a reduction in biodiversity. More crops also require more water, and in the case of corn, large amounts of nitrogen fertilizer. Increased fertilizer use can lead to pollution of lakes and streams from run-off and to more nitrous oxide, a greenhouse gas that can destroy ozone.Did You Know? Iogen, a company based in Ottawa, is at the forefront of cellulosic ethanol research. They are currently the only company with a facility for the commercial manufacture of cellulosic ethanol.
Alternatives to Food Crops for Biofuel Production
The good news is that food crops are not necessary for the production of biofuels. Oil from algae may be able to replace soybean as a starting material for biodiesel and ethanol can be made from cellulose (cellulosic ethanol), a polysaccharide component of plant cell walls. Cellulosic ethanol can be made from agricultural waste products, non-food plants such as switchgrass, wood chips, and waste from the pulp and paper industry. These materials would not compete with food crops or require the clearance of land.
In the end, it isn't biofuels that are bad, but the way they're made. As long as we stop trading away food for fuel, biofuels will be a powerful source of energy.
"Quick Guide: Biofuels", BBC News, Jan. 24, 2007
"Ethanol: FAQ. The relative merits of alternative fuel are still hotly debated", CBC News, May 13, 2008
"Grass Makes Better Ethanol than Corn Does", Scientific American, Jan. 8, 2008
Iogen Corporation, http://www.iogen.ca/index.html
"ABC's of Biofuels", U.S. Department of Energy, Energy Efficiency and Renewable Energy, Biomass Program
Tollefson, J. (2008) Not Your Father's Biofuels. Nature 451: 880-883.
Herrera, S. (2006) Bonkers for Biofuels. Nature Biotechnology 24: 755-760.
Candace Webb received her Ph.D. in molecular biology from the University of Ottawa in 2006, but now lives in Southern California.When not writing, she spends her time volunteering, hiking, painting,and hanging out at the beach