In this paper, we present the conceptual design of a wave-powered aquaculture farm (WPAF), in which a wave energy converter (WEC) is co-located with a salmon aquaculture farm in the Northeast United States. We employ an optimization algorithm to minimize cost-per-yield (USD/kg fish) for the WPAF system and investigate the tradeoffs between different design variables in the proposed conceptual design. The optimization algorithm adjusts the geometry of the WEC, the size of the net pens in the aquaculture farm, and the fish stocking density for a specific installation site. Our results highlight key drivers for the viability of a WPAF based on deployment locations and sensitivities to these drivers.
As the world's population continues to grow, aquaculture—with its ability to produce high-quality low-emissions protein without any specific need for land, freshwater, or fertilizer—will play a necessary role in ensuring adequate food supplies. Competition for near-shore space, episodes of poor water quality, and environmental considerations have motivated farmers to move their operations further offshore (Gentry et al., 2017). However, a disadvantage of aquaculture farms is that energy needs, such as for nutrient disbursement, are mostly met by diesel generators (U.S. Department of Energy, 2019). Preliminary research has shown that it may be feasible to replace fossil-fuel power generation at offshore aquaculture farms with wave energy converters (WECs), thereby enabling the aquaculture farm to be self-powered by renewable energy. This approach has been highlighted by the U.S. Department of Energy (DOE) as one near-term application for marine renewable energy resources to power the Blue Economy (LiVecchi et al., 2019). The DOE defines the Blue Economy as "the sustainable use of ocean resources for economic growth, improved livelihoods, and jobs while preserving the health of ocean ecosystems" (LiVecchi et al., 2019).
Given that WEC technology is immature and offshore aquaculture is an emerging market in the U.S., there is an opportunity to co-design the two systems for a wave-powered aquaculture farm (WPAF). The existing literature shows several recent studies assessing the co-location of WECs with aquaculture farms. Garavelli et al. (2022) studied the feasibility of co-locating offshore aquaculture farms with wave energy devices in the U.S. They identified California and Hawaii to be suitable sites based on the estimated wave energy resources and aquaculture farm energy needs. Clemento et al. (2023) found potential sites of different types of WECs co-located with offshore aquaculture farms along the Portuguese coast. Their study revealed more details about the design requirements of WPAFs but did not provide a systematic approach for the optimal design of a WPAF. Albatern, a Scottish wave energy developer, is investigating the possibility of using its WaveNET devices to power an offshore finfish aquaculture farm (Campbell, 2017). In China, the Guangzhou Institute of Energy Conversion designed a semi-submersible open-sea finfish farm powered entirely by wave and solar energy (Ma et al., 2022).
