MARINE MULTI-USE – COPRODUCTION OF RENEWABLE ENERGY AND REGENERATIVE BLUE FOOD IN SCANDINAVIA'S LARGEST OFFSHORE WINDFARM

Pressure on the coastal zone and offshore waters in Europe is increasing, in particular as a consequence of the expansion of offshore wind farms (OWF) [1]. At the same time we look to the sea for future food production to reduce pressure on land. With the recent UN Biodiversity Beyond National Jurisdiction Treaty and the EU Ocean Pact, the international focus on protection and restoration of the sea calls for responsible governance and management structures. Marine Multi-Use (MU), where space, infrastructure and services are shared between several actors [2] is suggested for 1) Optimising use of ocean space, 2) Boosting efficiency, reducing footprints and increasing safety of operations, and 3) Enabling the circular blue economy with the potential to increase global low trophic aquaculture (LTA) production by 132% using 10% of existing and planned OWF area for production of seaweed and mussels [3]. Realising this potential, however, requires adaptive governance frameworks that recognise both engineered ecosystem services and disservices across ecosystems, marine activities and value chains [4].

Outcomes of the WIN@sea project

Since 2023, a pilot scale lowtrophic aquaculture (LTA) site in the OWF at Danish Kriegers Flak (DKF) in the Baltic Sea has been established, operated and decommissioned as part of the the WIN@sea and OLAMUR projects. Here, joint MU procedures between OWF operator and LTA producer was demonstrated: site selection, risk assessments, shared wind and wave forecasts, joint maintenance operations and Crew Transfer Vessel (CTV) undertaking regular monitoring of site status, environmental parameters and biodiversity. Low salinity limited the seaweed productivity at DKF, but mussel settling and growth showed potential for production of marine protein. Dynamic 3D ecological models were used for predicting yields and ecosystem services and further taken into a site selection tool for identifying optimal sites for LTA within OWF, considering also local carrying capacity. Based on project data, LifeCycle Analysis is in progress for documenting the environmental and economic viability of the MU concept in the Danish Baltic and North Sea basins. The concept and dilemmas of sharing the space at sea has been developed into a board game for communicating Marine MU and ocean literacy in the Danish education system.

Figure 1. Concept figure of the Multi-Use prototype installed and run over 3 years in the Danish Krieger Flak Windfarm [3]. In the windfarm, production of mussels and seaweed take up nutrients and carbon, and the blue biomass is used for food, feed or biomaterials. The removal of nutrients mitigates eutrophication.

Acknowledgment

The project WIN@sea constitutes one of three case studies in the EU Mission Ocean Lighthouse project OLAMUR. The project is supported by the VELUX FOUNDATION, Aage V. Jensen NATURFOND and the European Union, grant no. 101094065. WIN@sea and OLAMUR embrace the EU Mission Ocean Charter.

References

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Schupp MF, Bocci M, Depellegrin D, Kafas A, Kyriazi Z, Lukic I, Schultz-Zehden A, Krause G, Onyango V, Buck BH (2019) Toward a Common Understanding of Ocean Multi-Use. Frontiers in Marine Science 6. doi:10.3389/fmars.2019.00165

Maar M, Holbach A, Boderskov T, Thomsen M, Buck B, Kotta J & Bruhn A. Multi-use of offshore wind farms with low-trophic aquaculture can help achieve global sustainability goals. 2023. Nature Communications, Earth and Environment. doi.org/10.1038/s43247-023-01116-6

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