Abstract
Ocean renewable energy (ORE) and offshore aquaculture are two industries that are likely compatible for colocation; ORE has the potential to provide power for offshore aquaculture and can decrease the environmental impact of operations by providing power at sea and replacing the reliance on diesel. This report defines co-location as the sharing of marine space between aquaculture and ORE as well as ORE providing power to aquaculture operations.
All forms of energy that can be derived directly from the seas and oceans are collectively known as ORE. Energy resources from the ocean are large, geographically diverse, and can be a sustainable alternative to providing power for offshore aquaculture. Each technology used to extract energy from waves, tides, ocean currents, or thermal and salinity gradients presents both advantages and challenges for aquaculture. Wave energy devices can be used for onshore, nearshore, or offshore aquaculture. They are particularly well suited for offshore aquaculture, though co-located wave and aquaculture projects will need to be in areas that avoid waves that are too large for the aquaculture system or too small for the wave energy device to be effective. Tidal energy devices may be more suitable for nearshore aquaculture operations, though the flow speed of tidal currents in energetic tidal channels could be a challenge for aquaculture operations. Both wave and tidal device technologies are more advanced than the other ORE technologies. Ocean current energy is generally located in offshore areas that feature high current velocities. For this reason, ocean current technology may not be suitable for offshore aquaculture because these locations present challenges for underwater operations such as net repairs and diving. Ocean thermal energy conversion (OTEC) has the potential to be used for onshore, nearshore, and offshore aquaculture in tropical and subtropical regions. OTEC can provide cold, nutrient-rich water with fewer pathogens and bacteria and can produce desalinated water for use in aquaculture production. Salinity gradient technologies are usually located nearshore and provide brackish water that can be supplied to aquaculture operations; however, these technologies are less developed than other forms of ORE. Solar photovoltaic (PV) and offshore wind are also assessed in this report as alternative renewable energy sources for powering aquaculture operations.
Worldwide, the aquaculture industry continues to increase. This expansion, coupled with increased competition for space among various marine uses, has led to an interest in shifting operations farther offshore. By moving away from coastal areas, aquaculture offers an important market opportunity for ORE. To develop appropriate ORE power systems for aquaculture and advance the co-location of the ORE and offshore aquaculture industries, understanding the energy demands and energy-intensive resource requirements for different aquaculture operations is crucial. Currently, data from the aquaculture industry on specific energy needs is limited, particularly for offshore aquaculture.
This report presents the available energy information for several operations within the global aquaculture sector, including nearshore and offshore Atlantic salmon, nearshore Asian seabass or barramundi, and nearshore oyster and mussel operations. As this report demonstrates, energy demands vary greatly by operation and species. Additionally, each source of energy information reports energy requirements differently, making it difficult to compare systems. The available energy information from marine-based aquaculture operations described in this report helps to provide a picture of the energy requirements worldwide.
Aquaculture projects that are being developed have begun to include renewable energy technologies (ORE as well as solar PV and offshore wind energy) in their designs and planning. The synergistic opportunities for colocated aquaculture and renewable energy can provide a multifunctional use of space and resources, creating opportunities to automate operations for safety and sustainability. Several projects, both past and present, are researching or have successfully implemented renewable energy to meet the identified energy demands of a variety of aquaculture operations. This report highlights 12 case studies, exploring projects that have used ORE, solar PV, offshore wind technologies, or hybrid solutions to meet energy demands of aquaculture. These case studies include all marine-based aquaculture types (finfish, shellfish, crustacean, and seaweed; nearshore and offshore) and a diverse range of renewable energy technologies. The key lessons learned from these projects are related to the lack of funding and the high cost of renewable energy technologies, long and costly consenting and regulatory processes, and uncertainty among stakeholders and regulators about the effects of a device on aquaculture operations. Both offshore aquaculture and ORE are relatively new industries, but the opportunities and challenges related to co-locating these marine uses can be identified from existing and planned projects. The opportunities and challenges for co-locating ORE and offshore aquaculture have been categorized under three themes: technical and operational processes, regulatory processes (including environmental and social aspects), and economic impact. Examples of opportunities under the theme of social acceptance are the sustainable and efficient use of marine space and the development of multi-use platforms. Examples of challenges under the theme of technical and operational processes are limited energy storage and the low levels of ORE device commercialization.
To overcome the challenges and capitalize on the opportunities identified in this report, recommendations are provided to expand the potential for co-location and further understanding of powering offshore aquaculture with ORE. The recommendations are classified using the same themes identified from the opportunities and challenges. These recommendations include increasing the accessibility of information about energy demands for all types of aquaculture (nearshore and offshore; finfish, shellfish, seaweed, etc.; at varied geographic locations), creating partnerships between ORE and aquaculture industries to generate pilot project opportunities, conducting research on the environmental and social effects of co-location, identifying countries with planning and licensing frameworks that may foster co-location, and encouraging governments to provide funding for research efforts and industry development.
Overall, this report provides a comprehensive look into offshore aquaculture as a market for ORE by identifying ORE technologies to be used, aquaculture energy demands, case studies and lessons learned, opportunities and challenges, and finally recommendations to advance the potential for co-location.
Watch the OES Webinar: Study of Offshore Aquaculture as a Market for Ocean Renewable Energy for a full breakdown of the report.