An Input-output Analysis of Two Green Microalgae Oil Production Systems

Abstract

The objective of this paper is to show the economic and environmental effects induced by construction and operation of a system that produces fuel from green microalgae using input-output analysis. We compared two systems. The first is a simplified photobioreactor (PBR) that utilizes fallow and domestic farmland. The second system is comprised of large and open ponds in overseas with relatively long hours of sunlight. A large part of the induced economic effect in constructing a small system comes from the cost of plastic materials needed to build the PBR. When constructing a large system overseas, civil engineering and water costs are quite high. Electricity costs make up a large part of the induced economic effect from operations. We also analyzed the sensitivity of plant profitability to change in growth and oil content rates of microalgae, and to how residue remaining after oil extraction is used. It is important to improve oil productivity of microalgae and to make high quality products from residue such as fertilizer or feedstuff, in order to improve profitability. However, production of high-quality products from residue emitted more CO₂ than production of low-quality products such as solid fuels.