Biodiesel production from microalgae: Exergoeconomic and exergoenvironmental assessments

Exergoeconomic and exergoenvironmental assessments can be combined to help improve algae biodiesel production, leading to a more cost-efficient, environmentally sustainable, and competitive biofuel industry. These assessments provide insights to balance economic and environmental considerations and make informed decisions for optimizing biofuel production processes. Exergoeconomic and exergoenvironmental assessments are carried out for an algae biodiesel production plant to identify the cost and environmental aspects of the products. To this end, the Life Cycle Assessment methodology is employed along with the SPECO approach. The plant produces algae biodiesel (1000 kg) and glycerin (93 kg), and comprises five phases: algae cultivation, oil extraction, transesterification, biodiesel separation, and methanol recovery. The specific cost per exergy unit for the biodiesel and glycerin produced are 11.54 US$/GJ and 14.45 US$/GJ, respectively. The specific environmental impact obtained for biodiesel is 4.67 mPt/MJ, and for glycerin, it is 5.83 mPt/MJ. The photobioreactor and centrifuge #1 obtained the worst exergoeconomic and exergoenvironmental performances. The photobioreactor also achieved the highest cost and environmental impacts associated with destroyed exergy (435.92 US$ and 45350.2 mPt). Improvement efforts should be directed to the photobioreactor and centrifuge #1, helping to optimize the economic and environmental performance of this biofuel production process.