There are two proven business models currently producing significant 1st generation biofuels in the United States using agricultural feedstocks: (1) fuel ethanol production via fermentation of sugars from corn starch; and, (2) biodiesel production by way of transesterfication of vegetables oils to methyl esters - better known as biodiesel.
Fuel ethanol production has exceeded 10 billion gallons of annual production and is principally derived from starch extracted from yellow dent corn harvested in the Midwestern U.S.
Biodiesel production approached 700 million gallons per year during 2008 and is primarily produced from soybean oil, canola oil, palm oil and animal fats.
Opportunity for fuel ethanol production in North Carolina from local feedstocks requires competitive feedstocks with Midwestern corn. 1st generation fuel ethanol from starch and sugars is well understood and the Biofuels Center of North Carolina is actively seeking and assessing alternative crops suitable for the state that yield starch and sugars competitive with Midwestern corn delivered into North Carolina. This requires improved economics for North Carolina farmers and a delivered price to a local fuel ethanol plant competitive with corn.
The Biofuels Center is actively assessing multiple crops including:
sugarbeets (genetically modified for North Carolina-type climates)
Decreases in the market value of petroleum-based diesel fuel and increases in soybean oil value have idled many biodiesel producers across the U.S. and in North Carolina. Byproducts from the North Carolina’s swine and poultry industries has proven a viable source of lipid (fat) feedstocks for small-scale biodiesel manufacturing. Long-term viability for biodiesel production in North Carolina requires a greater availability of fats and oils, providing competitive cost structures to petroleum-derived diesel fuel and improved economics for North Carolina farm practices.
The Biofuels Center is actively assessing multiple crops including:
canola
sunflower
Next generation biofuels, often referred to as cellulosic biofuels, are under development and supported by the Biofuels Center of North Carolina in a number of ways. Particular attention is being paid to:
switchgrass
miscanthus
Valuation is being assessed based on tonnage per acre yield and on the biofuels that can be processed from that biomass. In turn, value to the North Carolina farmer will be quantified including an accounting of any existing revenue from the land where biofuels crops can be grown.
The U.S. Department of Energy (DOE) funded “The Aquatic Species Program” in 1978 tasked with investigating the use of algae for the production of energy. The program shifted focus to algae oil production in 1982 and from 1982-1995 the majority of the program was focused on the production of transportation fuels, notably biodiesel. In July 1998, DOE published the report, A Look Back at the U.S. Department of Energy's Aquatic Species Program: Biodiesel from Algae. Since the DOE program, interest and private investment in algae development for biofuels production has heightened and increased yet neither economic viability nor commercial production volume has yet effectively demonstrated or achieved.
Algae offers the potential to provide both biomass and oil productivity in large scale quantities suitable for biofuels development. Technical and business opportunities are developing around species variation to optimize oil output for transesterification to biodiesel. Additional opportunities exist with thermochemical processing of algae as a feedstock for the production of FT diesel, mixed alcohols and biogasoline.
The Biofuels Center engages with companies and organizations working with algae where key issues around algae proliferation, biomass output and/or oil production are addressed in the business and technical development strategy.
Duckweed
Duckweed is showing promise as a biofuels feedstock based on its capacity to proliferate and produce functionally high yields of starch, oil and/or protein. Starch from duckweed can be useful for fuel ethanol fermentation and production. In turn, oil can be used for biodiesel production. In both cases, residual protein has high value in multiple markets including animal nutrition.
Switchgrass
Switchgrass is a giant, warm-season perennial grass native to North America high in cellulose, making it attractive as a biomass crop for cellulosic ethanol production in North Carolina. The tiny seeds are planted from late April to early June. Most of the first year’s photosynthate goes into root development in preparation for a long life span. Therefore, very little production is expected the first year. In subsequent years, the switchgrass is harvested after the plants go dormant, usually after the first killing frost. Yield during the second year should be about 4 to 6 tons per acre and then averages 6 to 8 tons per acre.
Adequate phosphorus and potassium levels in the soil are important for establishing switchgrass. However, annual maintenance application of fertilizer should be low to moderate. It is thought that since switchgrass is a perennial species, much of the nutrients in the foliage is translocated into the crown root system.
NC State University is conducting research on the agronomics of switchgrass at the Clayton research station and on the Williamsdale Farm near Wallace, North Carolina. The Biofuels Center has planted four varieties on the Oxford campus.
With a life span of 10 to 20 years, an average yield of 6 to 8 tons per acre, and low maintenance inputs, the economics of switchgrass production can be competitive with other crops. With varietal improvement, switchgrass yields might approach 10 to 12 tons per acre per year.
Giant Miscanthus
Giant Miscanthus (an “energy grass”) is a perennial warm season grass in the sugarcane complex that has considerable potential as a biomass crop in North Carolina to supply feedstock for cellulosic ethanol production and for gasification to gasoline processing. Giant Miscanthus has been bred to be sexually sterile and therefore propagates via asexual rhizomes.
Rhizomes are used to establish new stands and are planted in early spring. Some production will be realized the first growing season, but the main objective is to get the plants established for many years of production. During the second year, the plants will be in large clumps, and the canes grow to 12-15 feet in height. As temperatures cool in the fall, the dark green foliage fades to buff and drops, leaving the stems for harvest. Harvest is accomplished using commercially available hay harvesting equipment.
Giant Miscanthus is characterized as having broad adaptability, high water and fertilizer use efficiency, excellent pest resistance, and tremendous biomass production. Research at N.C. State University is underway to evaluate the performance of these crops across North Carolina, develop production practices and recommendations, breed and develop improved varieties, and improve efficiency of bio-processing and cellulosic ethanol conversion.
Barley
Barley is a winter annual grass crop that is very similar to wheat, but often yields more bushels per acre. Harvest time for barley is usually a couple weeks earlier than wheat, which is advantageous to farmers double-cropping their winter grass crop with soybeans. This is because earlier planted soybeans have a yield advantage over those planted later. In other words, soybeans planted on 1 June after barley harvest will typically out-yield those planted 15 June after wheat harvest.
The high starch content of barley makes it an interesting renewable energy crop for fermentation into ethanol. Hulless barley, a genetic variation of regular barley, has the potential to produce higher starch per acre. More research must be conducted to evaluate the value of barley for farmers and ethanol producers.
Industrial Sweet Potatoes
Industrial sweet potatoes grow similarly to edible sweet potatoes, but their roots have much higher starch content. Compared to corn, industrial sweet potatoes have the potential to produce 30% more starch per acre. The high potential for starch production makes this kind of sweet potato a crop of interest for bioethanol production. For them to be profitable for farmers to grow and be sustainable for processing into ethanol, input costs must be kept to a minimum and yield must be maximized.
The Biofuels Center is funding research conducted at Oxford and Clinton research stations for N.C. State University scientists to address these issues. This research is focused on three areas:
Developing a novel planting system using “cut seed pieces” similar to planting Irish potatoes
Developing mechanical harvesting equipment
Breeding varieties that yield high volumes of ethanol
To hear N.C. State University researchers Dr. Craig Yencho and Dr. Jonathan Shultheis discuss their industrial sweet potato project, click here.
The industrial sweet potato at the center of the picture was harvested from fields on the Biofuels Campus in 2009. It weighs more than 16 lbs. The smaller, whole, example to the left is the same size as a typical edible Number 1 table sweet potato one would find at the super market. The example to the right is the sorting equivalent of a jumbo table sweet potato.
Grain Sorghum
Grain sorghum (sometimes called “milo”) is a summer annual grass. Visually it resembles corn, and is processed into biofuels using the same technique. Grain sorghum seeds are round in shape, yellow-to-reddish in color, and develop in a cluster at the top of the plant (in contrast to the more oval-shaped yellow seed that develop in ears on the corn plant).
The high starch content of the seed makes it a potential feedstock crop for fermentation into ethanol. Grain sorghum currently has few markets, leading to its limited production in North Carolina. Demand from future fermentation ethanol plants will potentially increase its production.
Although grain sorghum lacks the yield potential of corn, it requires significantly less water and nutrient inputs, and therefore could become a viable rotation crop in certain soils. Breeding new high-yield, drought-resistant hybrids can make grain sorghum a profitable crop for farmers and an economical feedstock for ethanol producers.
Grain sorghum, North Carolina Biofuels Campus, Oxford, September 2009
Sweet Sorghum
Sweet sorghum is a summer annual grass crop that has been grown in limited amounts in North Carolina for local molasses production. The juice extracted from the stalks provides a source of aqueous sugar that is easier to convert into ethanol than it is to convert starch and cellulose into ethanol. Production inputs are thought to be less than that for corn. Low inputs and a high yield of easily fermentable sugars make sweet sorghum a potential crop to produce renewable liquid transportation fuel.
To help determine the sustainability of sweet sorghum as an energy crop, the Biofuels Center is funding research conducted by NC State University scientists at Oxford, Wallace, Plymouth and Clayton research stations in North Carolina. This research is focused on developing cost-effective methods to produce fermentable sugars from sweet sorghum by addressing questions concerning large-scale production, processing, and storage. The research is designed to: (1) develop a mechanized harvest and juice expelling system; (2) determine the best agronomic practices to produce sugars and quantify the efficiency of converting the sugar into ethanol; and, (3) identify beneficial uses for the crushed stalk residue.
Sweet sorghum nearly obscures the harvester during a demonstration at Williamsdale Bioenergy Field Laboratory October 2008.
Wheat
The U.S. produces 77.1 million metric tons of wheat straw annually, which has the potential to produce 54 million metric tons of fermentable sugars. Wheat straw, which is comprised of 70% complex carbohydrates, can serve as a low-cost feedstock for production of fuel ethanol.
North Carolina's leading producers of wheat production are the following counties: Robeson, Union, Beaufort, Pasquotank, Wayne, and Tyrrell.
Sugarbeets
Hybrid sugarbeets are being designed for use as an ethanol fuel feedstock. To optimize their performance, these hybrids are designed to produce a maximal amount of sugar. One of the appeals of producing these hybrids is their economic benefit: the hybrids, unlike traditional sugarbeets, do not need to be optimized for table top use. In fact, the hybrids should produce higher fermentable sugars for higher fuel ethanol output.
Syngenta, a global leader in sugarbeet seed production, has conveyed interest in testing six independent cultivars from existing hybrid programs for application in North Carolina across the state's adaptive acreage. Sugarbeets are not a typical North Carolina crop, though the new tropical varieties may prove to grow well in our climate.
Quick Facts
A number of countries already have working bioethanol plants that use sugarbeet as the source of biomass (U.K., Czech Republic, India, Germany, etc.)
The U.S. crop of sugarbeets produced a total of 31,912 thousand tons in 2007
The U.S. is the world’s 4th largest producer of sugar, and more than half of the sugar is produced from sugarbeets
U.S. sugarbeets are generally grown in areas with cooler climates, however, some sugarbeets are grown in warmer climates
Sugarbeets have a much larger yield per hectare than wheat (The EU currently produces 2 million more tons of sugarbeet than wheat on 20 million less hectares of land)
DuPont and BP formed a partnership in 2006 to work on biobutanol from sugarbeets
Soybeans
Soybeans are a summer annual legume crop that has been grown in North Carolina and much of the U.S. for decades. The harvested seed are separated into meal and oil by a combination of mechanical and chemical extraction processes. Historically, large soy processors have scaled their business to provide the high protein meal needed by the livestock and poultry feeding industry. The co-product – oil – in spite of its many uses in the food industry, accumulated over the years. Surplus oil and the resultant low price enticed soybean commodity groups to promote the conversion of soybean oil into biodiesel.
The economics to justify profitability was easy. Later increases in the value of the oil changed the economics. With this sequence of events, soybeans became the standard for biodiesel production and the benchmark against which to evaluate other oil-producing crops. Currently, soybean oil is too expensive for regular conversion to biodiesel.
Canola
Canola is a winter annual crop that can be grown in North Carolina to produce high oil-content seed. Canola seed oil is suitable for biodiesel or food-grade vegetable oil. The meal is suitable for dairy rations and egg-laying poultry rations. Canola is planted between mid-September and mid-October and harvested in June.
Sunflowers
Sunflowers are a summer annual broadleaf crop that is usually known for its large showy flower head that rotates during the day, following the angle of the sun. There are two types of sunflower: one is confectionary and is edible, and the other is for oil.
The high oil content makes sunflower seed a potential renewable energy crop. The staff at the Biofuels Center and the North Carolina Department of Agriculture research station in Oxford are working jointly on testing sunflowers, evaluating their potential for growing oil for biodiesel.
Duckweed
Duckweed is a tiny aquatic plant that is highly efficient in utilizing soluble nutrients found in livestock or municipal wastewater. Researchers at NC State University have demonstrated that, when grown on the nutrient-rich effluent from hog production, duckweed can be manipulated to produce large amounts of biomass that has either high protein content or high starch content. This research indicates that duckweed has the potential to be a viable, renewable energy crop for ethanol production.
An added benefit of duckweed is its ability to remove nutrients from agricultural and municipal wastewater. The Biofuels Center is funding continuing duckweed research conducted at a hog farm near Zebulon, North Carolina. For more on this grant-funded research and an interview with the researcher, click here.
Other collaborators include Aeroglide (sharing in the cost of drying equipment) and Novozymes (providing enzymes for fermenting duckweed to ethanol). Tasks of this project include:
Creating a scaled-up version of the duckweed cropping system
Developing a post-harvest handling procedure
Determining the ethanol yield from dry duckweed biomass
Performing an economic analysis of the overall process
The goal of this project is to evaluate the feasibility of using duckweed biomass to support yeast fermentation to ethanol for biofuels production.
Algae
Algae is perhaps the most promising of all the feedstocks for the production of biofuels in terms of the sheer volume of oil it could produce. If research proves true, the volume of oil it could produce dwarfs that of other feedstocks. Lab scale research indicates that first-generation algae production could produce 4,000 gallons of oil per acre - versus 50 to 100 gallons for other oil crops. Scientists believe that amount could be doubled to 10,000 gallons or more per acre - the catch? It hasn't been proven at scale and research into algae as a feedstock has shown only promise and no large-scale viability - yet.
Quick Facts
Some species of algae could be ideally suited to biodiesel production due to their high oil content (some well over 50% oil), and extremely fast growth rates.
Algae can be grown on marginal land, so they would not compete with food crops. They can also be grown in saltwater and wastewater.
Over the long-term, algae cultivation facilities also have the potential to absorb or 'capture’ waste CO2 directly from industrial facilities such as power plants.
Algae can grow as much as 100 times faster than agricultural crops.
Barley is a winter annual grass crop that is very similar to wheat, but often yields more bushels per acre. Harvest time for barley is usually a couple weeks earlier than wheat, which is advantageous to farmers double-cropping their winter grass crop with soybeans. This is because earlier planted soybeans have a yield advantage over those planted later. In other words, soybeans planted on 1 June after barley harvest will typically out-yield those planted 15 June after wheat harvest.
Duckweed is a tiny aquatic plant that is highly efficient in utilizing soluble nutrients found in livestock or municipal wastewater. Researchers at NC State University have demonstrated that, when grown on the nutrient-rich effluent from hog production, duckweed can be manipulated to produce large amounts of biomass that has either high protein content or high starch content. This research indicates that duckweed has the potential to be a viable, renewable energy crop for ethanol production.
