We report the performance of an advanced kelp cultivation system for offshore and exposed ocean environments. The field test was completed in the Gulf of Maine in 2022. The project is funded by the US Department of Energy’s ARPA-E program to develop technologies that can enable large-scale macroalgae cultivation in deep water. Multiple new technologies were deployed in the field test, including a unique mooring layout, unconventional materials, novel anchors, and a robotic anchor installation tool. With two seasons of field tests completed, project team members are using collected data to evaluate the cultivation structure and component technology performance, to improve upon those designs, and to better inform the concept’s economic feasibility.
The desired scales of production, harsh offshore environment, permitting restrictions related to marine mammals and low-cost requirements for offshore macroalgae aquaculture present a challenging engineering design problem. To approach economic feasibility our system integrates: shared use of infrastructural components, scaling efficiencies, structural resilience in overlapping modularity, and strategic agronomic processes. Our system sets the typical hectare scale longline farm within the context of massive (square kilometers scale) arrays of semi-independent farm “modules” supported by a lattice of novel multi-line moorings capable of increasing structural efficiency and resilience through distributed accommodation of hydrodynamic loads. ROVs designed to install the anchors enable low-cost deep-water deployments. Wave actuated tethered hydrofoil upwellers integrated into the mooring system harness ambient renewable wave energy to elevate deep cold nutrient rich seawater enabling conditions capable of extending temperate macroalgae growth seasons (tested separately from pilot field trials due to permitting restrictions). Fiberglass rods replace conventional ropes as mooring lines and growth substrate to reduce the risk of marine mammal entanglement.
This presentation will focus on characterizing and evaluating the performance of our proposed kelp cultivation system and component technologies through the lens of collected data and observations from our recent pilot scale field trials.