Developing Switchgrass as a Bioenergy Crop

The utilization of energy crops produced on American farms as a source of renewable fuels is a concept with great relevance to current ecological and economic issues at both national and global scales. Development of a significant national capacity to utilize perennial forage crops, such as switchgrass (Panicum virgatum, L.) as biofuels could benefit our agricultural economy by providing an important new source of income for farmers. In addition energy production from perennial cropping systems, which are compatible with conventional fining practices, would help reduce degradation of agricultural soils, lower national dependence on foreign oil supplies, and reduce emissions of greenhouse gases and toxic pollutants to the atmosphere (McLaughlin 1998). Interestingly, on-farm energy production is a very old concept, extending back to 19th century America when both transpofiation and work on the farm were powered by approximately 27 million draft animals and fueled by 34 million hectares of grasslands (Vogel 1996). Today a new form of energy production is envisioned for some of this same acreage. The method of energy production is exactly the same - solar energy captured in photosynthesis, but the subsequent modes of energy conversion are vastly different, leading to the production of electricity, transportation fuels, and chemicals from the renewable feedstocks. While energy prices in the United States are among the cheapest in the world, the issues of high dependency on imported oil, the uncertainties of maintaining stable supplies of imported oil from finite reserves, and the environmental costs associated with mining, processing, and combusting fossil fuels have been important drivers in the search for cleaner burning fuels that can be produced and renewed from the landscape. At present biomass and bioenergy combine provide only about 4% of the total primary energy used in the U.S. (Overend 1997). By contrast, imported oil accounts for approximately 44% of the foreign trade deficit in the U.S. and about 45% of the total annual U.S. oil consumption of 34 quads (1 quad = 1015 Btu, Lynd et al. 1991). The 22 quads of oil consumed by transportation represents approximately 25% of all energy use in the US and excedes total oil imports to the US by about 50%. This oil has environmental and social costs, which go well beyond the purchase price of around $15 per barrel. Renewable energy from biomass has the potential to reduce dependency on fossil fhels, though not to totally replace them. Realizing this potential will require the simultaneous development of high yielding biomass production systems and bioconversion technologies that efficiently convert biomass energy into the forms of energy and chemicals usable by industry. The endpoint criterion for success is economic gain for both agricultural and industrial sectors at reduced environmental cost and reduced political risk. This paper reviews progress made in a program of research aimed at evaluating and developing a perennial forage crop, switchgrass as a regional bioenergy crop. We will highlight here aspects of research progress that most closely relate to the issues that will determine when and how extensively switchgrass is used in commercial bioenergy production.