Floating solar powers seaweed farming


The EU-funded UNITED project is demonstrating the potential of integrating marine activities such as aquaculture with offshore renewable resources.

Floating renewables, and particularly floating solar, is gathering growing interest as land real estate becomes scarcer and more sought after.

The next obvious step is to integrate these resources with aquafarming type activities and this is now being demonstrated by two Dutch companies, which are pioneering the integration of offshore solar with a seaweed farm.

The farm, located at the North Sea Farmers test site 12km off the coast of Scheveningen, a district of The Hague, is the work of marine energy developer Oceans of Energy and the seaweed processor The Seaweed Company.

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Oceans of Energy had previously tested a near coast offshore solar unit, which was found to be able to withstand the harsh marine conditions, including two winter storms. The current solar plant, which with the seaweed nets is set on 61,000kg of steel anchors with 11m-long, 2.5t buoys, is designed to withstand waves of up to 13m.

“It is very special that we have now accomplished the generation of clean energy as well as production of food at sea, because both are important necessities of life,” says Allard van Hoeken, CEO of Oceans of Energy.

The operation is now under monitoring prior to the expected first seaweed harvest in May of this year.

The project is one of five demonstrations in the EU-funded UNITED (Multi-Use offshore platforms demoNstrators for boostIng cost-effecTive and Eco-friendly proDuction in sustainable marine activities) initiative.

The 36-month project launched in January 2020 is focussed on the technologies and business issues of such operations with five demonstrations, and aims to provide a roadmap for future multi-use sites.

Multi-use demonstrations

Two of the other four demonstrations are also focussed on aquaculture. The German demonstration led by Kiel University of Applied Sciences is investigating the potential for blue mussel and seaweed cultivation in combination with wind energy production at the Fino 3 wind research site 80km offshore.

The Belgian pilot led by Universiteit Gent is testing the potential for flat oyster aquaculture using the poles of offshore wind turbines as artificial oyster reefs.

The other two demonstrations are tourism focussed, although only one, the Danish pilot, is associated to offshore infrastructure. The aim in this case is to enhance the tourism potential of the Middelgrunden wind farm located off the coast of Copenhagen. Visits have been run for years but challenges remain around access and insurance and there may be potential for new multi-use opportunities such as fishing or diving at the site.

The fifth Greek pilot aims to integrate tourist activities such as scuba diving to aquaculture.

Oceans of Energy claim that its technology is ready to be scaled up to hundreds of megawatts. By using just 5% of the Dutch North Sea, particularly the space between wind turbines, half of the energy demand of the Netherlands could be generated, the company says.