Algae-Based Beneficial Re-use of Carbon Emissions Using a Novel Photobioreactor: a Techno-Economic and Life Cycle Analysis

Abstract

Despite the many advantages of microalgae, the feasibility of large-scale cultivation requires significant amounts of carbon dioxide (CO₂) to enable high growth rates. A synergistic union typically proposed for the supply of CO₂ is the coupling of algal cultivation with emissions from power plants. This study investigates the sustainability of a novel microalgae platform coupled with coal-based flue gas. The proposed system consists of a novel photobioreactor (PBR) for the production of biomass followed by a two-stage dewatering process. A systems model, which quantifies the CO₂ and energy consumption of the proposed system, was developed, and the minimum biomass selling price (MBSP) was determined by a techno-economic analysis (TEA). TEA results indicate that a facility with the capacity to capture 30% of the emissions from a 1-MW power plant requires a biomass production of 1280 metric ton per year, which when scaled to a nth of kind facility can produce biomass at a MBSP of $2322 per ton. The environmental impact of the proposed facility was determined by a life cycle assessment methodology, and results indicate a carbon capture potential of 1.16 × 10⁴ metric tons of CO₂ equivalent. In addition, an energy analysis indicates a desirable net energy ratio of 0.1, which is lower than conventional PBRs. Discussion focuses on the requirements to reduce biomass production cost, including research investment areas for increasing productivity while decreasing energy requirements.