Techno-economic analysis of microalgae production for aquafeed in Norway

The sustainability of the aquaculture sector depends mainly on the search for alternative sources to fishmeal and fish oil, one of which is microalgae. However, there are few feasibility studies of the microalgae process chain. This work aimed to address this gap through a TEA of microalgae (Phaeodactylum tricornutum) production. The TEA combines process modelling, engineering design and economic evaluation. As a result, different projections are obtained, yielding the breakdown of capital investment and operating costs. The study is based on pilot-scale experimental results using tubular PBR in Norway. This TEA shows that 29.48 t of biomass per ha of facility and year would be a real productivity. At PBR scales of 1 and 100 ha, microalgae could be produced for 108.26 or 44 €/kg DW of harvested biomass respectively. Artificial light is indispensable for microalgae production in Norway, as its absence would represent a 50% lower productivity and a cost increase of 95%. Producing the final product as a powder represents a 1.20% greater cost. Not only does the production under more favourable climatic conditions (southern Spain) removes the need for artificial lights and greenhouses, but it also would imply greater productivity (39.02 t/ha/year) and a reduced cost (23.08 €/kg DW of disrupted and dry biomass) at a scale of 100 ha. The main factor affecting CAPEX is the PBR, which range from 49.48 to 96.37% of the MEC. As for OPEX, the most critical elements vary with the projection: labour, energy, utilities, and other costs. The competitiveness of microalgae for aquaculture depends on a combination of different factors. Reducing the cost of the PBR and greenhouse, increasing the PE and widening the temperature range of the culture could reduce the cost by a further 76%.