Journal of Energy Bioscience 2024, Vol.15, No.5, 326-336 http://bioscipublisher.com/index.php/jeb 331 6 Case Studies 6.1 Pilot projects Several pilot projects have been conducted to evaluate the feasibility and performance of switchgrass as a feedstock for cellulosic ethanol production. One notable study managed switchgrass as a biomass energy crop in field trials across 10 farms in the midcontinental U.S. The results demonstrated that switchgrass produced 540% more renewable energy than nonrenewable energy consumed, with greenhouse gas emissions from cellulosic ethanol derived from switchgrass being 94% lower than those from gasoline (Schmer et al., 2008). Another study evaluated three process designs for producing ethanol and electricity from switchgrass, finding that mature technology designs significantly improved both process efficiency and cost relative to base-case cellulosic ethanol technology (Laser et al., 2009). Additionally, a high-resolution techno-ecological model was used to simulate various scenarios for growing switchgrass around a commercial-scale cellulosic ethanol biorefinery in Kansas, showing that the greenhouse gas footprint of ethanol production could be reduced by optimizing soil cultivation and fertilizer application rates (Field et al., 2018). 6.2 Economic and environmental impact The economic viability and environmental impact of switchgrass-based ethanol production have been extensively studied. A system dynamics model projected that cellulosic ethanol production from switchgrass is economically viable with advanced bioconversion technologies, providing significant environmental benefits such as greenhouse gas reductions and water use savings (Jin et al., 2019). Another study conducted a technoeconomic analysis of six biomass pretreatment processes, revealing limited differentiation in economic performance but highlighting the importance of monomer sugar and ethanol yields (Tao et al., 2011). Furthermore, a spatial multi-feedstock procurement landscape analysis found that including switchgrass in the feedstock mix for a cellulosic biofuel plant could reduce production costs and the carbon footprint, especially when grown on marginal land (Sesmero et al., 2021). Lastly, a life cycle assessment comparing various biomass feedstocks for cellulosic ethanol production indicated that switchgrass-derived ethanol could reduce fossil fuel consumption by 81% and greenhouse gas emissions by 65-77% compared to gasoline, although it did not reduce all environmental impact categories (Daystar et al., 2015). 7 Economic Impact of Switchgrass-Based Biofuel Production 7.1 Economic feasibility and cost reduction strategies Switchgrass has shown promise as a viable feedstock for cellulosic ethanol production, but its economic feasibility is a critical factor for large-scale adoption. Studies indicate that switchgrass can be economically viable, especially when advanced bioconversion technologies are employed. For instance, a system dynamics model suggests that cellulosic ethanol production from switchgrass is economically viable and can provide significant environmental benefits, such as greenhouse gas reductions and water use savings (Jin et al., 2019). Additionally, field trials have demonstrated that switchgrass can produce 540% more renewable energy than the nonrenewable energy consumed, highlighting its potential for high net energy yields (Schmer et al., 2008). Cost reduction strategies are essential for making switchgrass-based biofuel production more competitive. One approach is to grow switchgrass on marginal lands, which are typically less expensive and do not compete with food crops. This strategy not only reduces the cost of land but also minimizes the carbon footprint of biofuel production (Sesmero et al., 2021). Moreover, genetic modifications to switchgrass have shown potential in increasing ethanol yield by more than two-fold, thereby improving the economic viability of the crop (Shen et al., 2013). 7.2 Economic implications for farmers and industries The economic implications of switchgrass-based biofuel production extend to both farmers and industries. For farmers, the willingness to grow switchgrass is influenced by several factors, including contract terms, harvest flexibility, and financial incentives. Studies have shown that shorter contracts, greater harvest flexibility, crop insurance, and cost-share assistance increase the likelihood that farmers will grow switchgrass for bioenergy
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