Spatio-temporal techno-economic assessment of the algae-based supply chain: A proof-of-concept for North-West Europe

The growing world population is in need for new sustainable resources for healthy food, animal feed and chemicals. Algae produce a variety of compounds via conversion of CO2, nutrients, and light, and offer potential as renewable feedstock. However, producing microalgae is costly. Therefore, new economically viable supply chains must be developed. A variety of techno-economic assessments (TEA) has been performed to gain insight in the economic feasibility of algae production systems and refineries. While a TEA provides insights relevant to the technical and economic feasibility of a process, geographical conditions must be considered since the regional characteristics influence process feasibility and supply chain design. This paper presents a spatio-temporal TEA by combining a dynamic TEA model and a supply chain design optimisation model, MooV. The dynamic TEA outlines the conditions of the processes to reach a techno-economic feasible case as well as mass balances and OPEX and CAPEX of the different potential processes in the chain. MooV combines these parameters with geographic specific parameters such as the locations of activities and the characteristics of the transport network to define the optimal supply chain configuration (e.g., location and process type and capacity) based on minimal cost. The approach is demonstrated by year-round cultivation of Nannochloropsis gaditana in a horizontal tubular photobioreactor in 3 regions in North-West Europe. The analysis indicates that the cost per kg DM algae output can vary considerably (+/- 40 %) depending on the region and the set-up of the supply chain. Including geographic characteristics as well as comparing different supply chain design options are essential to come to a viable business case. The approach can also be applied to different algae strains, different regions and different process options.