Autotrophic production of biodiesel from microalgae: An updated process and economic analysis

Abstract

A technical evaluation of a plant for biodiesel production from microalgae was investigated in which a novel configuration of a CPR (closed pond photobioreactor) is proposed. The entire process was simulated by Aspen Plus® and optimized energetically in order to obtain the best profits in energy terms.The design and sizing of the process equipment was performed to obtain a realistic estimation of costs, considering both CAPEX (capital costs) and OPEX (operating costs). The economic analysis evaluated the profitability of the complete process at industrial scale referred to a CPR of 1 km2 of surface area as the base for calculation. In order to ensure an acceptable economic profitability a sale price of oil of $ 18.35/gal was obtained, corresponding to $ 21.11/gal of biodiesel.These results were compared to those of other recent studies, confirming that at the current state of technology the production of biodiesel from microalgae is not competitive with respect to that of conventional diesel, and a breakthrough in technology is needed to bridge this gap maybe by means of other valuable co-products from the same process. A future outlook is eventually reported.