In the global marketplace for cultivated macroalgae, raw product is traded as a commodity regardless of the ultimate end. New kelp producing regions in the north Atlantic and northeast Pacific have nucleated from food-focused, community-scale starting points. However, recent research initiatives in the United States and European Union have incentivized commodity scale development for macroalgae biomass beyond niche-food products including animal feed, biorefinery processes, biofuel production and ocean carbon dioxide removal (Blue Carbon/CDR) which is the focus of this assessment.
Recent efforts have taken a technoeconomic analytical (TEA) approach to assess the viability of scaling production to achieve high-volume end uses of farmed kelp, including CDR. These efforts are informative but focus on largely theoretical production systems which inherently encompass high variability and uncertainty in model inputs. However, recent works by Coleman et al. (2022a,b) provide detailed “baseline” TEAs based in real world application of currently employed kelp farming technology from nursery to harvest. These efforts have highlighted the importance of realistic TEA’s with integrated Life Cycle Assessments to account for emissions within the production system and the impact on the per unit cost of carbon sequestration.
Building from the Coleman et al. (2022) baseline model, we propose a framework for expanding the integration of LCA and TEA for modeling several CDR-focused kelp production scaling pathways from cradle to grave (in this case, nursery through sequestration) (figure 1). We will present a pathway to comprehensive Lifecycle Sustainability Assessments (LCSA) in which a Social-LCA (SLCA), TEA, and LCA are integrated. Even when optimized, macroalgae CDR will require considerable ocean space and potentially unforeseen social implications in addition to the ecological ones. Integrating the potential social-ecological and socio-economic impacts and benefits of different production pathways as well as of different carbon sequestration/avoidance related product end uses (direct sinking vs product substitution for example) will be important to achieving full sustainability of the sector.
References:
Coleman, et al. (2022a) "Identifying scaling pathways and research priorities for kelp aquaculture nurseries using a techno-economic modeling approach." Frontiers in Marine Science 9: 894461.
Coleman, et al. (2022b) "Quantifying baseline costs and cataloging potential optimization strategies for kelp aquaculture carbon dioxide removal." Frontiers in Marine Science: 1460.