Fossil fuels are used in more than 95% of the global transportation markets, but the demand for biofuels is growing at a rate ten times faster than the demand for oil. The use of biofuels, ethanol, and biodiesel for the transportation industries increases energy independence and reduces greenhouse-gas emissions. Biofuels are produced from renewable resources, largely from agricultural products.
The production of biofuels in the quantities that are needed to make a significant impact on reducing oil imports and greenhouse-gas emissions requires increased agricultural production. That change in agricultural management has the potential to impact food supplies and degrade soil and water resources.
Historical Background and Scientific Foundations
The use of biofuels in the transportation industry is not new. In 1900, German inventor Rudolf Diesel (1858– 1913) exhibited his new engine at the World Exhibition in Paris, France. He ran the engine on peanut oil. In 1912 Diesel suggested that vegetable oils would be the fuel of the future for his diesel engine. In 1925, Henry Ford (1863–1947), a leader in the U.S. automobile industry, promoted corn-based ethanol as the fuel of the future for the automotive industry.
It took most of the 20th century for these predictions to be revived. During World War I (1914–1918) and
World War II (1939–1945) there was some mixing of ethanol with gasoline in the United States to extend supplies but the ready availability of cheap petroleum postponed all serious efforts to produce biofuels for the transportation markets until the supply crises of the 1970s.
The Brazilian government first started promoting the use of sugarcane-based ethanol for the transportation market in the 1970s to boost the economy of a distressed sugarcane industry and to reduce petroleum importing. Sweden was also impacted severely by the 1970s oil import crises and provided government incentives to move toward biofuels. The rest of the world did very little to switch to biofuels until recent political instability and environmental concerns about greenhouse-gas emissions prompted a shift in governmental policies toward the promotion of biofuels.
Ethanol production more than doubled to nine billion gallons between 2000 and 2005. Biodiesel production did not start as early, but production of biodiesel quadrupled during the same period. The leading producer of ethanol today is Brazil with close to 5,000 million gallons produced in 2005 from sugarcane. The United States is second in ethanol production with close to 4,500 million gallons produced from corn in 2005. Bio-diesel is mainly produced in Europe with Germany leading at 507 million gallons from rapeseed in 2005 and France was second with 135 million gallons from soybeans.
Ethanol is produced by a fermentation process, which is an energy intensive process. However, because growing plants remove carbon dioxide from the atmosphere, even the fact that fossil-fuel energy is used in the production of ethanol, and carbon dioxide is emitted when ethanol is used as fuel, there is a net reduction in atmospheric carbon dioxide when ethanol is used to replace gasoline. Depending on the specific processes used in the production of corn-based ethanol, greenhouse-gas emissions could be reduced by 15–40% compared to using an equivalent amount of petroleum-based gasoline.
Biodiesel is produced in chemical processes that are not as energy intensive as fermentation. The net gain of reducing carbon dioxide emissions from using pure biodiesel is over 43% and for hydrocarbon emissions is over 55%. Petroleum-based diesel fuels have had problems with particulate emissions that are reduced by 55% when biodiesel is used. Only nitrogen oxides increase in the emissions of burning biodiesel fuel. Biodiesel is not as useful in cold weather because it thickens more than petroleum-based diesel.
Both biodiesel and ethanol are used more as blends with petroleum-based fuels. Ethanol cannot be used as a blended fuel above 10% ethanol except in specially designed engines. FlexFuel gasoline engines are being promoted to use 85% ethanol–15% gasoline mixtures.
Impacts and Issues
In Europe it would take approximately 3 million acres planted specifically in crops for biofuel production to reduce the use of petroleum-based fuel by 1%. The issue of available land for biofuel crops that would provide enough biofuel to make a significant difference in the use of petroleum-based fuels is one that is not resolved.
The world population is growing at the rate of about 90 million people a year. Demands for both food and energy are increasing. There is competition for land to produce biofuel crops and land for food crops. There has been considerable progress in developing cost-effective technologies to produce ethanol from biomass such as the corn stalks and other woody waste materials in place of corn, but that technology is not expected to enter the biofuel market until at least 2012.
In addition to competition between food crops that are also sources of biofuels, the increased production of the crops could have a negative environmental effect as more fertilizer increases the nitrogen content of the run-off, compounding the negative environmental effects such as the dead zone that has been created in the Gulf of Mexico. Soil and groundwater degradation from increased crop production is a serious concern.
WORDS TO KNOW
: A fuel made from a combination of plant and animal fat. It can be safely mixed with petro diesel.
: The sum total of living and once-living matter contained within a given geographic area. Plant and animal materials that are used as fuel sources.
: A liquid engine fuel used in diesel engines, which ignite fuel vapor by increasing pressure in a cylinder rather than by an electric spark. Diesel engines tend to be more efficient than gasoline engines. Most diesel fuel is refined from petroleum, but diesel may also be made from vegetable oil, in which case it is termed biodiesel.
: Compound of carbon, hydrogen, and oxygen(CH3CH2OH) that is a clear liquid at room temperature; also known as drinking alcohol or ethyl alcohol. Ethanol can be produced by biological or chemical processes from sugars and other feedstocks and can be burned as a fuel in many internal-combustion engines, either mixed with gasoline or in pure form. Several governments, most notably Brazil and the United States, encourage the production of ethanol from corn, switchgrass, algae, or other crops to substitute for imported fossil fuels. Ethanol is criticized by some as being based on environmentally destructive agriculture, putting human populations into competition with automobiles for the produce of arable land, and providing little more energy (depending on the manufacturing process used) than is required to produce it.
: Chemical reaction in which enzymes break down complex organic compounds (for example, carbohydrates and sugars) into simpler ones (for example, ethyl alcohol).
: Fuels formed by biological processes and transformed into solid or fluid minerals over geological time. Fossil fuels include coal, petroleum, and natural gas. Fossil fuels are non-renewable on the timescale of human civilization, because their natural replenishment would take many millions of years.
: The fraction of petroleum that boils between 32°F (0°C) and 392°F (200°C).
: A complex liquid mixture that is mostly composed of hydrocarbons, compounds of carbon and hydrogen, that is separated into different products with different boiling ranges by a process called cracking.
Palm oil, the second largest source of edible oil, is increasingly being used for biodiesel. The source of 90% of the world's palm oil is Malaysia and Indonesia. Palm oil would have to be imported to Europe for biodiesel production, which would defeat the goal of sustainable energy from local renewable resources.
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“March 2007 Monthly Update: Global Biofuel Trends.” Earth Trends, World Resource Institute, 2007. < http://www.earthtrends.wri.org/updates/node180> (accessed August 16, 2007).