Stepp, Justin Wayne (2011-08). Discrete Event Model Development of Pilot Plant Scale Microalgae Facilities: An Analysis of Productivity and Costs. Master's Thesis.
America's reliance on foreign oil has raised economic and national security issues, and in turn the U.S. has been active in reducing its dependence on foreign oil to mitigate these issues. Also, the U.S. Navy has been instrumental in driving bio-fuel research and production by setting an ambitious goal to purchase 336M gallons of bio-fuel by 2020. The production of microalgae biomass is a promising field which may be able to meet these demands. The utilization of microalgae for the production of bio-fuel requires the implementation of efficient culturing processes to maximize production and reduce costs. Therefore, three discrete rate event simulation models were developed to analyze different scaling scenarios and determine total costs associated with each scenario. Three scaling scenarios were identified by this analysis and included a stepwise, volume batching and intense culturing process. A base case and potential best case were considered in which the culturing duration, lipid content and lipid induction period were adjusted. A what-if analysis was conducted which identified and reduced capital and operational costs contributing greatly to total costs. An NPV analysis was performed for each scenario to identify the risk associated with future cash flows. The research findings indicate that the intense culturing scaling scenario yielded the greatest model throughput and least total cost for both the base case and potential best case. However, this increased productivity and cost reduction were not significantly greater than the productivity generated by the stepwise scaling scenario, suggesting that the implementation of flat plate bio-reactors in the intense culturing process may be non-advantageous given the increased operational costs of these devices. The volume batching scenario yielded the greatest total cost L^-1 of microalgae bio-oil for both, indicating an inefficient process. The scaling scenarios of the base case and potential best case yielded negative NPV's while the stepwise and intense culturing scenarios of the what-if analysis generated positive NPV's. The base case is based on current technological advances, biological limitations and costs of microalgae production therefore, a negative NPV suggests that utilizing microalgae for bio-fuel production is not an economically feasible project at this time.