Techno-economic modelling analysis of microalgae cultivation for biofuels and co-products

The goal of microalgae for biofuels is not only to replace fossil fuel in quantity but also for the cost to be at parity with the existing fuel stock. Adopting this evolving technology would not only require a combination of technical and economic assessment, but also the confidence of key stakeholders. The main challenge is that there are multiple pathways and logistics related to the entire algal biofuel production chain, and each stage is subject to technical, economic, environmental and policy issues, making it difficult to determine the optimum option. Therefore there is a need for a holistic decision-making tool, which provides a clear choice of direction to all stakeholders. The study initially adopted a multi criteria decision-making approach called TOPSIS, using a case study of five alternatives of algal processes to produce either oil for transport or biogas for electricity generation via a wastewater treatment method. The TOPSIS technique is used to identify the most acceptable alternative that has the maximum distance from the negative ideal and the minimum distance from the positive ideal solution. The result shows the alternative 1 and 2 as the preferred ideal solution among the others. Because the method ranks alternatives according to attributes, it limits the technique to a more defined process and therefore it cannot provide an understanding of feedback effects such as policy, resource availability in a region, and possible scale-up issues affecting the process. These limitations make the TOPSIS a less powerful technique for assessing the overall microalgae supply chain. However it is feasible to adopt the TOPSIS approach and integrate it into a flexible Techno-Economic (TE) model to make a decision over defined processes.