Aquaculture America 2023

February 23 - 26, 2023

New Orleans, Louisiana USA

LARGE SCALE, OFFSHORE KELP PRODUCTION IN NORTH AMERICA: IDENTIFYING SCALING PATHWAYS AND R&D PRIORITIES FROM NURSERY TO HARVEST

Struan Coleman*, Adam T. St-Gelais, Tobias Dewhurst, David Fredriksson, Michael MacNicoll, Kelly Cole, & Damian C. Brady

 

The University of Maine School of Marine Sciences

University of Maine

Orono, Maine

struan.coleman@maine.edu

 



Farmed Kelp has great potential to serve as a low GHG raw material within fertilizer, pharmaceutical, nutraceutical, and biofuel supply chains. Similarly, recent research has focused on the cost and climate change mitigation potential of intentionally sinking kelp to remove atmospheric CO2 (i.e., Carbon Dioxide Removal, CDR). In emerging kelp farming regions, products are typically processed (e.g., dried or milled) and sold as food. Regardless of the eventual end-use for cultivated macroalgae, current production levels will need to increase to realize economies of scale, reduce per unit C emissions, and accelerate kelp farming down the technological learning curve. The current cost structure of small-scale farms is fundamentally misaligned with the cost structures of raw materials supply chains. The lack of data on the economics of kelp farming at offshore, exposed sites thus represents a critical information gap.

Our research team from the University of Maine, with partners from The University of New Hampshire and Kelson Marine Co., have developed a hyper realistic techno-economic analysis (TEA) and Life Cycle Assessment (LCA) modeling framework for large scale kelp farming in the Gulf of Maine. We quantified the costs, C emissions, and productivity of a 1,000 acre operation across the full production chain, from nursery (Coleman et al., 2022a) through ocean cultivation (Coleman et al., 2022b). We were able to alter key production parameters, such as nursery inputs, kelp yields, and the C content of fuel, to track sensitivities within the model in terms of $ and kg CO2eq per ton of kelp produced. We also ran a kelp CDR scenario in which farmed biomass was transported to an offshore site and intentionally deposited in the deep ocean.

The results of our analysis provide baseline cost estimates, highlight which elements of the production process may suffer from lack of scalability, identify C "hotspots", and prioritize R&D areas that would facilitate the continued expansion of the sector. The modeling framework is flexible and can be used in the future to track the potential cost and emissions savings of improved nursery or ocean cultivation, and farm designs that make efficient use of ocean space. 

References:

Coleman, et al. (2022a) "Identifying scaling pathways and research priorities for kelp aquaculture nurseries using a techno-economic modeling approach." Front. in Mar. Sci. 9: 894461.

Coleman, et al. (2022b) "Quantifying baseline costs and cataloging potential optimization strategies for kelp aquaculture carbon dioxide removal." Front. in Mar. Sci. 1460.