Bioenergy Crops for Illinois
As everyone knows, fossil fuel is a finite resource and is the accused culprit of global warming after the industrial revolution. Yet, economic development has a strong correlation with energy consumption. Consequently, seeking and developing alternative energy resources is required to maintain our high quality lifestyles. Although food-based biofuel is a relevant mature technology and lessens our reliance on fossil fuel, it has resulted in soaring food prices. In order to decrease food versus fuel concerns and satisfy the increasing need of energy consumption, developing advanced biofuel (e.g., cellulosic ethanol, biodiesel) is pivotal.

The current U.S. Renewable Fuel Standards (RFS2) set up the goal of using 21 billion gallons of advanced biofuels as a transportation fuel by 2022. In 2010, the U.S. Department of Agriculture (USDA) developed a regional strategy to meet the RFS2 mandate. In this report, Central-Eastern, one of the most potential regions, was expected to produce up to 9.1 billion gallons of advanced biofuel, which is near a half of the total mandate volume by 2022. Besides, it also suggests that the possible feedstock could be perennial grasses, biomass sorghum, crop residues, soybeans, and woody biomass. Therefore, the State of Illinois, in this area and known for its great agricultural productivity, should carefully consider which bioenergy cropping system is capable of meeting the mandate and more sustainable to the environment.

According to statistics, in 2010, the land in farms in Illinois was around 27 million acres or 75% of total land area, including 12.4 million acres of corn and 9 million acres of soybean. Despite the fact that USDA claimed it will only require 4.5% cropland and cropland pasture to produce enough advanced biofuel2, the land resource will be limited because of the projected population growth. Furthermore, corn production in Illinois ranked second in the country3, that is to say, the conversion of land use may dramatically affect food prices, so that an ideal bioenergy crop for Illinois should be able to be planted in marginal land and have high biomass yield.

However, merely these characteristics of bioenergy crops are not convincing enough for farmers to adopt new plants. Financial incentives are the main driving forces of their decision-making. For example, growing perennial grasses is fast to return the investment in comparison with woody crops. Furthermore, to compare with annual crops, perennial grasses demand less energy and money investment after the first year establishment. Taking these factors into consideration, I suggest that perennial grasses, such as switchgrass and Miscanthus x giganteus (Miscanthus), have more opportunities to succeed in Illinois.

Both miscanthus and switchgrass are warm-season grasses and can adapt to the cold temperature in Illinois. Yet, in terms of biomass yield, miscanthus outweighs other perennial grasses. Plant height is a crucial feature for selecting bioenergy crops. Over all, miscanthus can grow up to four meters per year, while switchgrass can only grow up to three meters. Moreover, the previous side-by-side trials demonstrated that the yield of miscanthus was three to four times higher than that of switchgrass in Illinois. The more biomass it can produce per acre, the less land it will need to produce the same amount of biofuel. Planting high yield bioenergy crops can minimize the land competing with food crops. From this point of view, miscanthus is a prospective bioenergy crop.

In addition, miscanthus seems to be able to utilize nutrients very efficiently, so it requires less nitrogen fertilizer annually than switchgrass. Khanna (2008) tried to calculate the costs of production for miscanthus and switchgrass and found that the fertilizer costs $57.39 (ha-1) for switchgrass and $40.42 (ha-1) for miscanthus per year. Applying less fertilizer is not only a financial incentive to farmers but also benefits the environment. Nitrate leaching from the cropland may contaminate groundwater by eutrophication. Also, nitrogen, a main greenhouse gas, could escape from the soil through volatilization and lead to global warming. For the reasons stated above, miscanthus is a more sustainable and economical option.

It is undeniable that miscanthus is not a perfect bioenergy crop. It still has many drawbacks that need to be addressed. For example, miscanthus is sterile, so expensive rhizomes asexual reproduction is required. Jain et al. (2010) reported that it cost approximately $1200 to establish an acre of miscanthus. On the other hand, it is cheaper to establish switchgrass because it can be reproduced by its seeds. Nevertheless, Khanna (2008) concluded that the breakeven delivered cost of miscanthus is lower than switchgrass while taking the opportunity cost of land into consideration5.

There is no single silver bullet, as the saying goes. In my opinion, monoculture over a wide area is not necessarily a good idea. It reduces the biodiversity and is more prone to pests, disease, and weather change; miscanthus in particular has low genetic diversity. There is no reason to restrict only one bioenergy crop in a certain region. For example, switchgrass, the top candidate of bioenergy crop of U.S. Department of Energy, can also be another choice for Illinois. Yet, in the current stage and single region, switchgrass does not appear to be as competitive as miscanthus in Illinois in terms of biomass yield, fertilizer application, and cost.

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[ 1 ]. Ghoniem, A.F., et al. (2011). Needs, resources and climate change: Clean and efficient conversion technologies. Progress in Energy and Combustion Science, 37(1), 15-51.
[ 2 ]. U.S. Department of Agriculture, (2010). A USDA regional roadmap to meeting the biofuels goal of the renewable fuels standard by 2022
[ 3 ]. U.S. Department of Agriculture, NASS (2011) Illinois Fact Sheet
[ 4 ]. Heaton EA, et al (2006). Miscanthus x giganteus: the results of trials alongside switchgrass (panicum virgatum) in Illinois. University of Illinois at Urbana-Champaign: Depart- ment of Plant Biology.
[ 5 ]. Khanna, M. (2008). Costs of producing miscanthus and switchgrass for bioenergy in Illinois. Biomass and bioenergy, 32(6), 482-493.
[ 6 ]. Jain AK, et al. (2010). An integrated biogeochemical and economic analysis of bioenergy crops in the Midwestern United States. Global Change Biology Bioenergy 2(5):217–234.