Determinants of economically optimal cassava-to-ethanol plant capacities with consideration of GHG emissions

• A Life Cycle Assessment of a cassava-to-ethanol plant in China is performed.
• Optimization methods are used to enhance the understanding of biomass logistics.
• The two methods are combined to investigate trade-offs between economy and ecology.
• Transportation-related specific GHG emissions are constant for optimal capacities.
• Ethanol/product price and conversion ratio are among the most important parameters.

The successful realization of biofuel plants depends on a number of economic and ecological factors. In this work, the production of bioethanol from cassava in China's Guangxi province is investigated by combining an economic optimization approach with results from corresponding Life Cycle Assessments. By using the potential plant's capacity as the optimization variable, it becomes possible to show the trade-offs associated with different capacities, especially with regard to the achievable profitability and the corresponding greenhouse gas emissions. In contrast to distinct case studies, this approach aims for the identification of optimal capacities from a continuous range of potential capacities. The combined assessment is then applied to a Chinese scenario to determine the effects of factors such as fertilizer application and of the conversion of fresh cassava to cassava chips to identify favorable options for potential future cassava-to-ethanol plants. In general, such modeling approaches are expected to facilitate the bioenergy plant planning by approximating the economic and ecological consequences of plants of different capacities.