CABBBIE

Photosynthetic biogas upgrading using nature’s own “bio-factories”, microalgae, may overcome the economic and environmental obstacles of biomethane production by co-producing biomethane and biofertiliser (digestate) with other bio-products via a Cascading Algal Biomethane Biorefinery System or CABBS. This novel biorefinery can not only maximise the use of the biomass resource but also potentially lower the cost and environmental impacts of biomethane while potentially improving process performance and the flexibility of operations. It also presents the opportunity for direct CO2 utilisation on or near-site through the production of biochemicals from microalgae. By allowing flexibility in the choice of bio-products derived from microalgae, this process can be adapted to local requirements within a bioeconomy system and can also possibly develop into a negative emission technology. However, as this is a nascent technology, significant research is required to scale-up and optimise the process, particularly with a focus on the Irish bioeconomy. Further research is also necessary to determine the actual costs and social and environmental impact of such systems besides developing business models, policy support and social acceptance to ensure rapid scale-up and industrialisation of this versatile biorefinery process.