Energetic Performance of Photobioreactors for Algal Cultivation

Microalgae are currently being investigated as a potential fuel crop. For algae to be an energy-efficient fuel crop, cultivation systems and operating conditions that have been optimized for biomass productivity have to be refocused toward energy production. In this work, data from the literature on a variety of algal photobioreactors (PBRs) were compiled to reassess them in terms of biomass productivity per unit energy input to the cultivation process. This assessment showed that PBRs that have been optimized for biomass productivity without considering the energy input did not necessarily perform well in terms of energy efficiency. This review recommends that selection of algal PBRs for energy production should consider optimal geometry for efficient utilization of incident light, and their operation should be based on the optimal sparging rate for efficient mixing to maximize energy efficiency