| | Benito Stradi, left, and Donal Day, both of the Audubon Sugar Institute, are involved in research on turning sugarcane into ethanol. (Photo by John Wozniak) |
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| | Grain sorghum could provide an affordable feedstock for an ethanol plant. |
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| | It is still not economically feasible to produce ethanol from sugarcane in the United States. (Photo by John Wozniak) |
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Renewable energy is the focus of the AgOutlook 2008 conference Feb. 25-27, 2008, in Monroe. Sponsored by the LSU AgCenter, the conference will help participants explore the opportunities a variety of renewable energy sources such as ethanol, biodiesel and other products can provide to increase agriculture’s contribution to the Louisiana economy. Register here.
Louisiana farmers and forest producers could find a silver lining in the cloud of rising fuel prices with the development of new fuels from crops they already grow or could grow.
“The LSU AgCenter has the resources to help develop value-added opportunities for rural Louisiana,” said David Boethel, LSU AgCenter vice chancellor for research. “The agricultural industry is looking for us to help them as they explore these opportunities.”
Boethel said agricultural production is a leading reason for supporting a biofuels industry in Louisiana. He also cited the state’s proximity to Houston, the fourth largest U.S. market, and the state’s broad-based transportation as grounds for pursuing research and development in bio-based fuels.
While ethanol generally is made from corn in the Midwest, other Louisiana crops – primarily sugarcane and grain sorghum – could provide affordable feedstocks for an ethanol plant. The major component of biodiesel currently is soybean oil, although other oilseeds also can provide equally good or better sources for the produce.
Corn ethanol requires 26 percent less fossil energy to produce than it contains, while cellulosic ethanol – made from whole sugarcane plants and similar plant materials such as grasses and wood – requires as much as 90 percent less energy to produce. Soy diesel production requires 69 percent less energy than it contains. Other oilseeds, such as sunflower, can produce as much as four times the amount of biodiesel per acre as soybeans.
The future of ethanol production in Louisiana can be divided into segments – that which can be produced immediately through traditional feedstocks such as molasses, milo or corn, and areas that must be expanded and are longer-term in development, such as ethanol from cellulose or new energy crops.
The U.S. Department of Energy and the U.S. Department of Agriculture produced what is called “The Billion Study.” The study reports that the biomass potential in the United States exceeds 1.3 billion tons per year – enough to produce biofuels to meet about 30 percent of the country’s annual oil consumption.
Ethanol Replaces MTBE
Ethanol is a high-octane fuel used primarily as a gasoline additive and extender. Since the late 1970s, methyl tertiary butyl ether (MTBE) has replaced lead as the primary gasoline additive in the United States. Over the past few years, however, several states have banned the use of MTBE as a gasoline additive because of environmental problems resulting in groundwater contamination. The reduction in use of MTBE and recent surging prices for petroleum-based fuels are dramatically increasing the demand for ethanol and the interest in ethanol production in the United States.
Ethanol can be produced from carbohydrates such as sugar, starch and cellulose by fermentation using yeast or other organisms. Current production of ethanol around the world uses two primary feedstocks – grain crops (primarily corn and wheat) and sugar crops (sugarcane, sugar beets or molasses). A 2006 cooperative research project between the LSU AgCenter and the Office of Energy Policy and New Uses in the Office of the Chief Economist, U.S. Department of Agriculture, evaluated the economic feasibility of producing ethanol from sugar feedstocks in the United States. These feedstocks included sugarcane juice, sugar beet juice, sugarcane or sugar beet molasses, raw sugar and refined sugar.
Ethanol from corn in the United States is produced by one of two processes – wet milling or dry milling. In wet milling, corn grain is soaked to facilitate separation of the grain into its component parts, with the starch from the grain fermented into ethanol. In dry milling, the corn grain is first ground into flour and then mixed with water and enzymes for fermentation into ethanol. Wet milling yields approximately 2.654 gallons of ethanol per bushel while dry milling yields approximately 2.75 gallons of ethanol per bushel.
The estimated production of ethanol is 19.5 gallons from one ton of sugarcane and 24.8 gallons per ton of sugar beets. One ton of molasses, a byproduct of sugarcane and sugar beet processing, would yield about 69.4 gallons of ethanol, and one ton of refined sugar would yield 141 gallons of ethanol.
Corn Cheapest Choice
Corn is still the cheapest feedstock available for producing ethanol in the United States. The costs of other feedstocks must be compared to corn for them to be economically viable over the long run. Given current and future prices for sugar and ethanol, producing sugar is the most profitable use of sugarcane or sugar beets.
The majority of ethanol produced by other countries around the world uses sugar crops as the primary feedstocks. Sugarcane is the predominant feedstock in these countries, although several countries use sugar beets. The relatively low market prices for sugar crops in many of these countries, compared to the United States, makes the production of ethanol from sugar crops economically feasible.
Converting cellulose into ethanol offers the potential for a wide variety of feedstocks to be used. A great deal of research is being conducted across the country to develop commercial processes to convert biomass into ethanol. Whole sugarcane plants, which produce a substantial amount of biomass per acre, could be a viable feedstock for such a process.
Adding Value To Sugarcane
Adding value to sugarcane has always been the mission of the AgCenter’s Audubon Sugar Institute. But that mission has taken a new twist in these times of high fuel costs. One of the newest projects is making ethanol from sugarcane.
The ethanol project is part of a cooperative venture with MBI International, a nonprofit spin-off of Michigan State University, and the Audubon Sugar Institute. The two organizations have received grants from the U.S. Department of Energy to produce value-added products from bagasse and molasses.
Bagasse, the fibrous material that remains after sugar is pressed from sugarcane, is currently burned as fuel in sugarcane mills. But researchers hope to increase the value of what is now considered a waste product. MBI International has a process for treating bagasse and other vegetative residues to convert them to sugars, which can be fermented into ethanol.
“The focus is adding value to cane biomass,” said Donal Day, a researcher at the institute. “This will allow the processors to get revenue from something other than the sugar. Ethanol from sugarcane is quite feasible, particularly at current prices.”
Ethanol out of biomass changes the historical approach to growing and processing sugarcane. Instead of growing the plant exclusively for sugar, producers could grow sugarcane for the total biomass.
“The leaves and tops are more amenable than bagasse for making ethanol,” Day said.
A preliminary analysis has shown that an ethanol plant in the Bayou Teche area could produce 62 million gallons of ethanol per year with materials from four area mills. Such use could extend the sugarcane season into the winter by harvesting the cane for ethanol rather than for sugar only. The energy required to produce ethanol from sugarcane is less than the energy requirement for producing ethanol from corn.
“The challenge is economics,” Day said. “We can do it in the lab. The technology is there, but the economics aren’t there yet to be commercially viable.”
One advantage of using bagasse as a source of biomass is that it is already being delivered to sugar mills while other products, such as corn stalks, have to be collected. The Audubon Sugar Institute has the capacity to move research from the laboratory to a pilot plant and eventually work with industry to bring the process into full production.
If the research proves fruitful, the process could result in establishing a plant that could use $23 million worth of raw products from Louisiana sugar mills to produce products with annual revenues in the range of $265 million. The plant and equipment would require capitalization of around $140 million.
Soybeans To Biodiesel
Biodiesel in the United States is commonly produced from soybean oil and yellow grease (recycled cooking oil from restaurants). Biodiesel is generally blended with petroleum diesel – B20 is 20 percent biodiesel while B100 is 100 percent biodiesel. Most tests show biodiesel performs better than petroleum diesel, but oil companies produce diesel fuel with distillates that remain after refining gasoline. So as long as refineries produce gasoline, they will also produce the base material for diesel.
Lubricity is a measurement of the lubricating properties of diesel fuel, and biodiesel has better lubricity than low-sulfur petroleum diesel. But biodiesel reduces fuel economy in an engine. The energy content of biodiesel is about 11 percent lower than petroleum diesel. So gallon-for-gallon, biodiesel must sell for less than petroleum diesel to be competitive in the marketplace.
Biodiesel is produced by converting vegetable oils or fats into fatty acids, which are then turned into esters. Most biodiesel is produced by reacting vegetable oils with methanol with sodium hydroxide as a catalyst. The reaction, known as transesterfication, produces methyl esters and glycerin, a saleable byproduct.
While ethanol requires large-scale facilities for production, biodiesel can be manufactured in smaller batches. Thus, farmers or others who have access to vegetable oils can produce biodiesel for themselves.
“We can make biodiesel today at 60 cents to 70 cents a gallon for feedstock,” said Bill Carney, coordinator of the LSU AgCenter’s W.A. Callegari Environmental Center. “It burns cleaner, has better lubrication qualities and produces less air pollutants than petroleum diesel.”
Soybeans yield about four times as much soybean meal – generally used as an animal feed – as oil, so soy oil is actually a byproduct of producing soybean meal. Researchers are evaluating other plants, such as rapeseed, sunflowers and Chinese tallow trees as sources of oil for producing biodiesel.
Shift To Corn
“High gasoline prices are helping sustain ethanol profits – even with the high cost of corn,” said LSU AgCenter economist Kurt Guidry. “Producers react to these high corn prices by shifting acres into corn production and will continue to do so as long as the profit potential for corn is greater than for those competing crops.”
Guidry said ethanol demand has been the main reason corn prices improved. He said if demand persists, market conditions in the fall of 2007 could mirror the fall of 2006, when prices of both corn and soybeans increased dramatically during a bidding war for acres.
“This could happen again as the market attempts to hold onto the acres it gained in 2007,” Guidry said. “With an improved supply and demand situation for soybeans and better price prospects, this bidding war could be more fierce as corn may find it more difficult to pull acres away from soybeans.”
AgCenter economists said rice and cotton acreage in some parts of the country will respond to changes in corn prices, and producers will plant less of those crops in favor of corn. Guidry said 2007 will see considerably less cotton, less soybeans and less rice in North Louisiana as farmers plant more corn.
Growing conditions in Southwest Louisiana are not favorable for corn, but soybeans are a viable crop in Southwest Louisiana with high soybean prices, said LSU AgCenter economist Mike Salassi.
Salassi said producers are looking for the cheapest feedstock per gallon of ethanol or biodiesel produced. “We can’t double ethanol production using only corn as a feedstock,” he said.
The economists agreed that long term, cellulose as a feedstock for biofuels is an alternative to food crops. Non-food feedstock crops include switchgrass, sweet sorghum and macanthus grass along with energy cane, a type of sugarcane that’s grown for its biomass rather than for sugar content.
The LSU AgCenter is one of 11 institutions of higher education in the Louisiana State University System. Headquartered in Baton Rouge, it provides educational services in every parish and conducts research that contributes to the economic development of the state. The LSU AgCenter does not grant degrees nor benefit from tuition increases. The LSU AgCenter plays an integral role in supporting agricultural industries, enhancing the environment, and improving the quality of life through its 4-H youth, family and community programs.
(This AgCenter Lead was updated on February 13, 2008, by Linda Benedict.)