Biodiesel production from microalgae Dunaliella tertiolecta: a study on economic feasibility on large-scale cultivation systems

Microalgae have attracted significant interest worldwide as a prospective biofuel feedstock. Currently, biodiesel potential of microalgae has been confined at lab scale; however, economic feasibility is a limiting factor for commercialization. Thus, development of large-scale production system is an essential element to assess economic feasibility as well as policy support needed to implement large-scale production. To answer this, Dunaliella tertiolecta was selected for biodiesel feedstock production among other isolates, having 1.244 g/L dry biomass yield and 37%w/w lipid content. Operational cost of biodiesel production was 3.19 USD/L for lab scale which can be reduced to 0.77 USD/L at large-scale production by integrated and efficient resource utilization, namely, natural seawater (NSW), as growth media and unproductive coastland for production site. Capital investment of USD 82019.89 was calculated for biodiesel production facility with 16.7 KL annual production for one-hectare unproductive land. Economic evaluation of 10 years of production resulted into net present value (NPV) of USD 750.91 and 5.18% internal rate of return (IRR). Capital recovery can be achieved in 7.76 years as per normal payback analysis. Additionally, NPV can be increased to USD 30355 by upscaling production to five times with 50% more biomass productivity that would result into 14.23% IRR. Efficient resource integration, multiple products and co-products with market linkages, and appropriate policy facilitation are key factors for commercial viability of microalgae biodiesel production.