Offshore wind developers and manufacturers are seeking opportunities to support production of fish, shellfish and seaweed at their offshore wind projects. Increasingly, this is being driven by the need to boost revenues as well as supporting biodiversity.
When the going gets tough, the tough get innovative. With so many offshore wind companies battling to make projects profitable, new approaches must follow.
It is with that in mind that a project in China has attracted our attention this week. Last Friday, Longyuan Power and Shanghai Electric Wind Power announced they have completed work on a deep-sea floating wind, floating solar and aquaculture project off the coast of Putian in eastern Fujian province. ‘Aquaculture’ refers to the breeding, raising and harvest of fish, shellfish and aquatic plants including seaweed.
The project is located in China’s National Marine Ranching Demonstration Zone on Nanri Island; and is made up of three 4MW floating turbines on semi-submersible foundations, lightweight floating solar modules, and a hexagonal area between the floating turbines for fish farming. The pair said their project “presents a new horizon for the industry” because of the combination of three emerging technologies, and it also highlights to us the role of aquaculture in unlocking additional value at assets.
Longyuan and Shanghai Electric are not the first companies to add ‘aquaculture’ to an offshore wind project, but they are among the first to stress the role that it could play in boosting economic growth. So far, most of the discussion around aquaculture projects at offshore wind farms have focused on biodiversity and social responsibility. These are both important, but developers have to focus on the financial bottom line.
Pairing floating wind with aquaculture may be new, but it is not the first development in China to take such an approach. In April 2023, Mingyang Smart Energy revealed it had developed a wind turbine foundation with an integrated net cage for fish farming; and it completed production on the first such system in July.
The company has since installed the first of these MyAC-JS05 systems in one of the 12MW offshore turbines at the 500MW Quingzhou 4 offshore wind farm in the South China Sea. Mingyang said the net cage is typhoon resistant; can raise up to 150,000 fish at any time in its 5,000 cubic metre area; and includes remote functions such as automated feeding, monitoring, detection and harvesting. It said each net cage could support 75 tonnes of fish production annually, generating €600,000 of extra revenue. That would be a significant financial uplift if installed across a whole project.
Offshore wind developers in Europe are pursuing similarly innovative approaches.
In November 2022, Dutch utility Eneco and offshore contractor Van Oord installed four oyster tables at the 129MW Luchterduinen project in the Dutch North Sea. Each oyster table is made from materials including concrete, weighs around 3,000kg each, and is attached to the scour protection at the base of an offshore wind turbine. These are intended to help oysters to survive and reproduce.
Also in the Netherlands, engineering group OOS International and research institute Deltares have developed a semi-submersible mussel farm that can be deployed at offshore wind farms in the North Sea; and, in February 2023, Amazon committed to provide €1.5m funding to support construction of the first commercial-scale seaweed farm between offshore wind turbines in the North Sea. The project is being led by the not-for-profit group North Sea Farmers; is set to produce its first harvest next spring; and is expected to produce 6,000kg of fresh seaweed during its first full year.
In addition, scientists who have studied the impacts of artificial reefs installed at the 752MW Borssele 1 & 2 wind farm in Dutch waters have reported that the reefs have attracted species including cod and lobsters, and helped both to proliferate.
That makes logical sense. Species that gather around offshore wind farms should be safer from commercial fishing practices, including trawling, than if they were in open water, and are thus better able to grow their populations. Of course, the irony is not lost on us that these species may be harvested by net cages in turbine foundations, assuming that approaches such as Mingyang’s become more widely adopted.
This is where developers may face questions over how they can balance their need for increased profitability at offshore wind farms with the ethics of aquaculture.
From a business perspective, it makes sense for developers to look at additions to offshore wind farms that help them to boost marine biodiversity in the short-term and open up longer-term opportunities for additional revenue generation. But we cannot shake the idea that developers will likely face ethical questions too. Does embracing ‘aquaculture’ show they are only fostering biodiversity for financial gain, rather than because they see biodiversity itself as a goal worth pursuing? Does this even matter if offshore wind turbines are helping to support fish stocks in the first place?
These are important questions that offshore wind developers may have to answer if they wholeheartedly embrace the potential for ‘aquaculture’. But, in a market where it is tough to take projects to financial close, many will see this trade-off as worth it.
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