Bio-energy system analysis: Profit, planet, and policy

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Aui, Alvina
Major Professor
Mba-Wright, Mark
Wang, Yu
Brown, Robert
Bai, Xianglan
Andersen, Daniel
Committee Member
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Mechanical Engineering
Climate change has escalated in the last decade, affecting every region globally, making it one of today's most important issues. As a response to climate change, the scientific community and politicians have been advocating the shift from a fossil-based economy to a bio-based economy as one of my many options. A bio-based economy refers to an economy that utilizes biomass for the production of goods, services, and energy. Using biomass leverages the biogenic carbon cycle of biomass, which can lower total greenhouse gas emissions. However, this transition is complex and hindered by the combination of technical, economic, and knowledge barriers. To overcome these barriers, public policies were designed and implemented to encourage demand, reduce financial challenges associated with the high production cost of bio-products, and stimulate the overall growth of the bio-based economy. This dissertation is a compilation of several case studies investigating the economic feasibility, environmental sustainability, and effectiveness of various policy designs for several bio-energy systems. The first chapter details the background and motivation, including the current state of climate change, an overview of a bio-based economy, technical challenges, and a review of recent relevant studies. Next, it also includes a comprehensive description of the methodology of each analysis and a review of recently published literature. This is followed by the first study (Chapter 2), which investigates the economic feasibility and environmental impacts of a waste-to-energy biopower anaerobic digestion system. The analyses suggest that a farm-scale anaerobic digester for power production is economically feasible and can reduce total greenhouse gas emissions. The next case study in Chapter 3 investigates the economic feasibility of utilizing cellulosic biomass for ethanol as a strategy to decarbonize the transportation sector. However, it is mainly inhibited by the high cost. Chapter 4 investigates the concept of learning-by-doing (LBD) as a strategy to overcome the high cost. Several cellulosic ethanol plants of different costs, capacities, and LBD rates were modeled. The impact of LBD is evaluated through forecasted cellulosic ethanol production for the next 20 to 30 years. The analysis suggests that the LBD effect can only be initiated when cost and capacity decrease, leading to 3.27 billion gallons of cellulosic ethanol production in 2040. The last case study in Chapter 5 further investigates other strategies such as policy support for cellulosic ethanol. The existing policy supports such as the Renewable Fuel Standard, Production Tax Credit, Cellulosic Waiver Credit, and Small Refinery Exemption were modified, modeled, and investigated. These policies were evaluated individually and as bundles. Finally, a cost-benefit analysis was employed to investigate the trade-off of cellulosic ethanol's economic costs and environmental benefits. Collectively, these case studies demonstrate the advantages and challenges while identifying bottlenecks of commercializing bioenergy systems.