June 2007
By Valerie Yeager
Today’s Dietitian
Vol. 9 No. 6 P. 42
Renewable energy may lessen U.S. reliance on foreign oil, but does developing biomass threaten sustainable agriculture?
Having recently moved to a new city, I’m naturally excited for the fresh experiences accompanying my relocation—the bright lights, endless dining possibilities, and world-class museums. The energy is tangible. Nevertheless, I’m perhaps most excited about one thing in particular: public transportation. No longer will I be standing at the fuel pump, watching the numbers skyrocket as I fill my gas-guzzling tank.
Even so, I still feel a twinge of horror every time I pass a gas station. Will the prices ever drop considerably? It’s unlikely, but the increasing popularity of biofuels such as biodiesel and ethanol—quickly gaining momentum as an unconventional substitute—will certainly help.
Biofuels are often applauded in the media as the magical solution to the energy crisis, replacing petroleum as the driver of our economy. But one can’t help but wonder: How will transforming products derived from popular crops such as corn and soybeans into fuel affect the food supply?
Seeking a Solution
At this point in the 21st century, the United States is faced with two critically important energy problems: our dependence on foreign oil and the climate-disrupting greenhouse effect. The United States imports 70% of its oil, and Al Gore’s An Inconvenient Truth demonstrates just how serious the climate issues are becoming. The world’s oil demand is continually growing while supplies are continually shrinking, leaving the political and economic stability of our nation and its environment at risk.
According to Dick Auld, PhD, of the department of plant and soil science at Texas Tech University, approximately 96% of the energy sources in the United States come from nonrenewable sources, such as the following:
• coal: 23%;
• petroleum: 40%;
• natural gas: 25%; and
• nuclear: 8%.
These nonrenewable resources will eventually run out, significantly impacting future generations if sustainable, renewable resources are not developed as a primary source of fuel. Unfortunately, there is no easy solution, especially when less than 4% of U.S. energy is currently produced from renewable sources such as solar, wind, geothermal, hydroelectric, and biomass (plant-derived material). Of these, biomass is making the most significant impact.
Ethanol and Biodiesel
Corn muffins. Corn flakes. Corn fuel?
The largest U.S. renewable energy source each year since 2000, biomass provides the only renewable alternative for liquid transportation fuel in the form of ethanol and biodiesel. Corn and soybeans are among the most popular sources of biomass used to develop fuel.
Mostly developed from sugar and starch crops, ethanol is a type of alcohol made by fermenting plant material. It burns much more cleanly than pure gasoline, so it releases far lower emissions. It can be combined with gasoline in any concentration up to pure ethanol. Worldwide automotive ethanol capabilities vary widely, and most spark-ignited gasoline-style engines operate well with mixtures of 10% ethanol.
Meanwhile, biodiesel is a fuel designed for diesel engines that is produced by blending petroleum diesel with refined vegetable oil. The blend most often available for consumers is 20% biodiesel, referred to as B20. Like ethanol, biodiesel releases significantly lower emissions than pure petroleum diesel.
To the surprise of many, biofuels aren’t exactly a new concept. In 1892, the first diesel engine was designed to run on peanut oil, and in 1908, the Ford Model T was designed to run on ethanol.
Only since the 1990s, however, have biofuels become more readily available to consumers. Demand for biofuels, by farmers and trucking companies in particular, is growing. Even tractor-maker John Deere is jumping on the bandwagon by shipping tractors and combines from its factories with biodiesel in the tanks. The price is roughly the same as pure petroleum diesel and even began selling at 4 cents per gallon less at some outlets during summer 2006.
The basic processes for converting biomass to biofuel are well-known and used commercially today. Two key reactions must occur to convert biomass to ethanol: hydrolysis and fermentation.1
Hydrolysis is the chemical reaction that converts the complex polysaccharides in the raw feedstock to simple sugars. In the biomass-to-ethanol process, acids and enzymes are used to catalyze this reaction. Fermentation is a series of chemical reactions that convert sugars to ethanol. The fermentation reaction is caused by yeast or bacteria, which feeds on the sugars. Ethanol and carbon dioxide are produced as the sugar is consumed.1
Problems on the Horizon
Food Supply
A concern not only to nutritionists and dietitians but also to biologists, environmental engineers, and farmers is food supply. Are the industrial methods currently used to produce crops popular for both food and fuel sustainable? According to Angie Tagtow, MS, RD, LD, an environmental nutrition consultant and immediate past chair of the Hunger and Environmental Nutrition Dietetic Practice Group of the American Dietetic Association, the answer is a resounding “no” for the following reasons:
• the high input costs, such as land prices, machinery, seed, herbicides and pesticides, fertilizer, storage, and transportation;
• the environmental insults from aggressive farming techniques, such as soil depletion and erosion, as well as pesticide and fertilizer runoff resulting in polluted waterways and contaminated water supplies; and
• the amount of energy it takes to grow, harvest, and transport these crops to fuel refineries outweighing the amount of energy generated from the fuel itself.
According to Tagtow, farmers in the Midwest are devoting more land to corn production, “further perpetuating a monocropping system, decreasing biodiversity, and further destroying the resilience of the soil and waterways.” Although these changes may not be immediate, the results will eventually make staggering transformations in the way people eat. “Agriculture is the foundation of the food system, and the subsidized agricultural products have influenced what we eat and the nutrition and health of our society. When monocrops are the norm and diversity dwindles, this is directly reflected in our diets,” she adds.
Finding a suitable, renewable source of fuel is clearly crucial, but at what price? As more crops are grown for ethanol production, the price of those crops will fluctuate. “As the demand for corn increases, I anticipate the price of corn will increase. As the price of corn increases, we will experience an increase in food costs and particularly with beef, dairy, pork, poultry, and eggs (livestock that rely on corn for feed). The price of food will be greatly affected if the price of petroleum and corn increases simultaneously,” says Tagtow.
“This is especially critical to low-income families who already devote 30% to 40% of their household income to food and will greatly impact the budgets of federal food and nutrition assistance programs, such as the Special Supplemental Nutrition Program for Women, Infants, and Children; Food Stamps; and School Feeding Programs,” she continues.
Genetic Engineering
Genetically engineering crops to ensure sustainability for both the fuel and food supply is an option, but it may wreak havoc on the ecosystem. Techniques such as accelerated domestication make for more efficient energy crops, but the genetic modification of these plants could take an invasive turn. One proposed biofuel crop, Miscanthus, can grow up to 8 feet in six weeks, acting essentially like a plant on steroids and overtaking surrounding crops that act as food sources for wildlife.
Also, genetically engineering a crop may alter its genes in ways other than just growth. “Some of the genes being engineered into corn to make it a better source of ethanol aren’t genes we want in the food chain. And without confinement, such as plant sterility, those genes could find their way into the corn that we eat,” says Albert Kausch, PhD, a plant geneticist at the University of Rhode Island. Overall, while genetic manipulation may be a quick fix to retain sustainability, the long-term effects could be disastrous.
The Future of Biofuel
Although it won’t entirely solve the problem, including more diversity in the biomass converted to fuel will help. Luckily, it is becoming more popular in research and technique for alternative sources beyond corn and soybeans to be used as biofuel sources. Among these emerging fuel sources are corn stovers and wheat stalks, fast-growing trees such as poplar and willow, and several perennial energy crops such as switchgrass. Switchgrass, a native plant of the tall grass prairies, grows up to 12 feet tall in one season and produces as many as 10 tons of plant material in one acre without genetic modification.
After all, corn and soybeans alone aren’t enough to make a dent in the nation’s dependence on oil. Researchers have estimated that the United States has a sustainable supply of roughly 1.4 billion tons of biomass each year that could be used specifically for the production of liquid fuels, which, using conventional methods, would provide only 30% of the fuel required for the nation’s annual transportation needs.2
Another helpful route is the increasing popularity of new techniques in the way biomass is converted to biofuel. Ethanol is currently developed using only the corn kernels because that is the only part of the ear containing the sugars that can be fermented and distilled to make ethanol. But corn stalks and husks—largely considered waste—may be more useful in biofuel production as advancements continually emerge.
Corn stalks and husks are made of cellulose, a polymer that is comprised of many sugar molecules strung together. If cellulose is treated with an appropriate catalyst—an enzyme capable of breaking it down into the sugars from which it is formed—these sugars can then be fermented and distilled to form alcohol. This change would make the corn-to-ethanol process far more efficient, allowing the corn kernels to continue to be used as food, avoiding the steep increase in agricultural prices that would occur if corn became a fuel supply source.
The conversion of corn husks and stalks to ethanol is only one example of the potential to efficiently convert cellulose into biofuels. Cellulose is the most abundant organic chemical that exists and trees, leaves, grass, and virtually all plant materials contain large amounts of it. Converting cellulosic biomass to ethanol is currently too expensive for use on a commercial scale, but that will hopefully change as new advancements materialize.
The Biofuels Innovation Program
In February, the National Wildlife Federation unveiled a proposal—the Biofuels Innovation Program—for the 2007 Farm Bill Energy Title to help farmers switch to growing a new generation of biofuel crops. The proposal promotes the production of biofuels and biomass through the following:
• encouraging production of dedicated perennial energy crop feedstocks in a sustainable manner that protects the nation’s soil, air, water, and wildlife; and
• providing financial and technical assistance for owners and operators to produce dedicated bioenergy perennial crops and crop mixes of suitable quality and in sufficient quantities to support and/or induce development and expansion of the use of the crop for the following:
- biofuels;
-
- power or heat generation to supplement or replace non–bio-based energy sources; and
- bio-based products to supplement or replace non–bio-based products.3
Essentially, the plan would enroll up to 5 million acres of land to promote the sustainable production of next generation biomass energy, such as switchgrass for ethanol and jojoba for biodiesel. Taking into account the concerns of invasive biologists, the plants used must be perennials native to the United States and not have the potential to become invasive.
The proposal also considers Tagtow’s concerns regarding the amount of energy it takes to transport crops to fuel refineries. For a facility that uses biomass to be economically viable, the biomass it utilizes must be grown within a relatively concentrated area to ensure manageable transportation costs. Most experts describe this area as being within a 50- to 70-mile radius of the facility. The Biofuels Innovation Program addresses this issue by requiring groups of landowners to come together to apply for funding as a project rather than as individual landowners. This way, crops are being transported from several farms in a local area rather than just one. Participants must collectively submit a written Bioenergy Project proposal to the secretary of the U.S. Department of Agriculture that includes the number of owners and operators participating; number of acres proposed for enrollment in the program; type and diversity of eligible crops to be grown; probability that the bioenergy crops proposed to be grown under this program will be utilized for the purposes of the program; and potential for positive economic impact on the local community.3
Conclusion
Our society is heavily reliant on several nonrenewable energy sources, such as petroleum, coal, and uranium, and biofuels alone will not be able to replace these sources and meet our present high-energy needs. “We must look to true renewable and sustainable energy sources such as solar, wind, and hydropower. These are true renewable and sustainable energy sources because they do not require continual inputs or degrade the environment and can be maintained now and for future generations. Using these renewable energy sources will decrease the competition with our food supply,” says Tagtow.
Tagtow urges dietitians to take an “active role with energy conservation and advocating for agriculture policy that supports a diet aligned with the Dietary Guidelines for Americans. Dietitians need to engage in critical thinking about how food is produced, processed, purchased, and consumed and how influences on our food system impact the availability, accessibility, quantity, safety, and nutritional profiles of foods needed for a healthy diet.”
Although the future energy crisis is unlikely to be solved by biofuels alone, they are likely to make a substantial impact on our energy future, as well as the future dietary habits of Americans. Adds Tagtow, “If future fuel resources rely on food sources, dietitians must be engaged in this dialogue.”
— Valerie Yeager is an editor and freelance writer based in Philadelphia.
References
1. U.S. Department of Energy — Energy Efficiency and Renewable Energy Biomass Program. “ABCs of Biofuels.” Available here. Accessed March 29, 2007.
2. Purdue University. “New Biofuels Process Promises to Meet All U.S. Transportation Needs.” March 14, 2007. Available here.
3. Biofuels Innovation Program. “A Proposal for the 2007 Farm Bill Energy Title.” Available here. Accessed March 29, 2007.