Environmental Impacts of Biofuels
See our 2007 report Fueling Oregon with Sustainable Biofuels for an in-depth discussion of the environmental impacts of producing and using biofuels.
Do biofuels help air quality?
Biodiesel is far cleaner than petroleum diesel, with significantly lower emissions of particulate matter, hydrocarbons, sulfates and cancer-causing air toxics. Biodiesel can emit more nitrous oxide, a smog-forming compound, but biodiesel’s lower hydrocarbon emissions mean that its overall smog-creating potential is 50% lower than petroleum diesel’s.
Adding ethanol to gasoline decreases emissions of carbon monoxide and helps reduce carcinogenic substances in gasoline such as benzene, toluene, and xylene. According to the EPA, a 10% ethanol blend can reduce benzene by 25% compared to gasoline. However, ethanol does result in slightly higher emissions of acetaldehyde. Ethanol also has a mixed impact on ground-level smog – some studies show an increase, others a decrease.
Do biofuels mitigate global warming?
Plant-based fuels have what’s called a “closed carbon cycle,” which means that the carbon dioxide released when they are burned is later used by plants, which are then used as a feedstock to produce more biofuel. In contrast, when petroleum fuel is burned, it releases carbon dioxide that has been stored for millions of years. Plants are able to recycle some, but not all of the carbon dioxide released by burning petroleum. On average, lifecycle carbon dioxide emissions from biodiesel are 78% less than petroleum diesel. On average, lifecycle carbon dioxide emissions from corn-based ethanol are 35% less than petroleum diesel. However the greenhouse gas benefits vary depending on how the biofuel is produced (see Fueling Oregon with Sustainable Biofuels for more details).
Do biofuels save energy?
Modern U.S. corn farming makes relatively intense use of energy and chemicals, and early ethanol plants were also energy intensive, raising concerns as to whether the ethanol being produced was worth the energy going into making it. However, both agricultural producers and ethanol processors have made great efficiency gains in recent years. Nearly all recent studies of ethanol’s energy balance conclude that for every unit of energy that goes into growing corn and turning it into ethanol, we get back about one-third to nearly two-thirds more energy as automotive fuel. These analyses account for all non-solar energy used to grow, harvest and process corn, and to produce ethanol in modern facilities, as well as the value an important byproduct of ethanol production – cattle feed.
Cellulosic ethanol is expected to have a much more favorable energy balance than corn ethanol, and biodiesel has a net energy gain of 220%.Click here to learn more about the energy balance of biofuels.
How else do biofuels impact the environment?
Biodiesel and ethanol plants are relatively clean industries compared to oil refineries. Biofuel refineries are closely regulated, and in most states must install the best available control technologies so that air and water emissions meet stringent standards. That said, locals communities should play a role in ensuring regulatory oversight.
The pesticides and fertilizers used for corn production raise serious environmental concerns, as well as the fact that corn requires intense irrigation. Thus it’s important to move quickly toward ethanol production from cellulose feedstocks. The stronger the demand for ethanol, the sooner commercialization of cellulosic ethanol will occur.
In the Northwest, canola is the major feedstock for biodiesel. It has the advantage of requiring relatively low water or pesticide inputs and as a rotational crop for wheat can actually boost wheat yields in the following year.
Another environmental concern is the importation of palm oil to the U.S. for conversion into biodiesel. Rainforests are being chopped down to plant palm plantations for conversion into both food oil and biodiesel. OEC does not support production of biodiesel from palm oil. We successfully convinced the City of Portland to require that fuel blenders not be allowed to meet the local renewable fuel standard with palm oil biodiesel, and we also ensured that the state's new renewable fuel standard for biodiesel cannot be triggered by palm oil biodiesel.
Shouldn’t our farm land produce food instead of fuel?
Worldwide food supply and demand are primarily influenced by agricultural and export policy and the politics of food availability, not by crops grown for fuel. Given that three-quarters of the corn produced in the U.S. is used to feed animals, there is no shortage of land currently devoted to corn production that could be converted to production of crops for human consumption. See Corn Prices Near Record High, But What About Food Costs? published February 2008 for a perspective from the U.S. Department of Agriculture.
There are certainly limits on producing biofuels from crops. Over the long run, other sources must be commercialized. Already biodiesel is produced from waste oils. Soon, ethanol will be produced from cellulosic materials like switchgrass and wood waste from forest-thinning. (In the case of the latter, we must be vigilant to ensure that the cellulose materials are derived from environmentally-sound forest thinning projects.) Other means of producing biofuels are being researched and developed. One future feedstock for biodiesel might be algae!
Can we completely replace petroleum with biofuels?
For most of the 20th century, we’ve consumed petroleum as though it would last forever. Experts disagree about how much petroleum is left and how long it will last. They do agree, however, that less new oil will be found and that prices will increase.
In Winning the Oil Endgame, Amory Lovins of the Rocky Mountain Institute estimates that one-fourth of U.S. oil needs could be met by a major domestic biofuels industry based on advances in biotechnology and cellulose-to-ethanol conversion.
While we can’t displace all petroleum with renewable fuels, they are one important piece of reducing our dependence on a finite and dirty fuel. We must also demand more fuel-efficient vehicles and develop lifestyles and communities that are less reliant on the automobile.
How can we reduce these environmental impacts?
The Oregon Environmental Council has prepared a set of guidelines, or best management practices, for production of biofuels. These practices would apply to agricultural and forestry producers of biofuel feedstocks as well as producers of biofuels at biorefineries. They are intended to be used as broad guidelines in areas such as soil management, water use, waste generation, and energy use. OEC believes these practices exemplify sustainability in the biofuels industry, and we will encourage producers to employ them wherever possible.