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New recommendations for offshore solar certification

Offshore solar energy has incredible potential and therefore the industry is developing certification and standardisation processes. As part of the North Sea Two (NS2) project, Oceans of Energy, Deltares, TNO, and DNV have carried out a unique testing activity under North Sea wave conditions in the Deltares Delta Flume. The results, available in a newly-published white paper, offer validations for structural performance for floating solar systems with solar modules at the seawater-level and recommendations to industry experts on the next steps towards certification of offshore solar.

“DNV experts specializing in offshore solar were invited to the Deltares Delta Flume to witness a full-scale laboratory test of the Oceans of Energy solar farm system. This testing program aimed to assess the performance of offshore solar systems. This attendance was crucial for enhancing DNV’s understanding of the structural and mechanical demands of these systems, exploring how testing activities can aid in developing offshore solar certification, and sharing insights gained from the project. By simulating offshore conditions, the tests provided valuable data on how these systems react to different wave conditions based on floater length.”

“The Delta Flume tests have provided useful insights into the behaviour of the floating system and individual components under severe wave loads”, Roderik Hoekstra, Deltares project lead, said.

“TNO is happy that we have contributed to this collaborative experiment in a unique experimental testing environment conducted by Oceans of Energy, Deltares, and TNO to validate hydrodynamic models and assess the impact of waves on solar panels”, Jan Kroon, TNO project lead, said.

“The NS2 Delta Flume tests have greatly increased our understanding of how our offshore solar systems surpass the high waves in the offshore North Sea environment. This collaboration together with Deltares, TNO, and DNV is of large importance in making progress towards certification of offshore solar.” said Fabian Koppes, Head of Product, Oceans of Energy “The learnings have contributed to industry success stories including the uptake of our offshore solar system by Shell & Eneco in the Crosswind’ Hollandse Kust Noord offshore wind farm in Summer 2025.”.

Offshore Solar Energy

Offshore solar has immense potential. As the push for renewable energy accelerates, offshore solar is emerging as a promising solution against pressing challenges for renewables on land. Additionally, integrating solar with offshore wind farms allows for the efficient use of existing infrastructure (as of the complementary energy generation profiles) and the improved utilization of the wind farm site space.

Standardized testing and certification processes are important for developing the industry further and to capture the immense potential. These standards are under development, and will contribute to ensuring that offshore solar farms can be deployed safely, cost-effectively, and with long-term stability.

Research and innovation

Research and innovation contribute to bridging this gap and gathering the required knowledge for developing offshore solar testing standards and certification. Collaboration between research institutes, technology developers, and certification bodies is needed.

An important research initiative is the North Sea Two Offshore Solar project (NS2), funded by the Dutch Ministry of Economic Affairs. Partners in the consortium project include Oceans of Energy, Deltares, DNV, and TNO.

In addition to a pilot operating 4-years in offshore conditions, the consortium conducted a unique, full-scale experimental test in the Deltares Delta Flume. The research considered the impact of wave action on various Oceans of Energy floating platforms. It also aimed to understand the behaviour of specific farms and the performance of PV modules in a controlled environment.

Large and small-scale testing

Experiments included testing at the prototype scale, with results showing that unique knowledge on floating solar panel movement can be gained this scale. These insights were of large value in addition to insights gathered during small-scale testing or by testing at sea.

Proto-scale testing therefore is an important step in the development of a standardised testing programme, which can eventually lead to the certification of large-scale marine applications. While small-scale testing is useful for understanding the dominant mechanisms that determine the behaviour of the rig and its impact on the mooring system, proto-scale testing – such as in the Delta Flume – allows for isolation of specific measurements and is therefore key for improving understanding the actual forces on individual elements, which are also difficult to get to scale.

White paper recommendations

The testing results have been published in a white paper titled “The Structural Testing of Offshore Solar Systems and PV-Modules by wave slamming in the Deltares Delta Flume”.

The paper provides a current overview on the development of this innovative technology to generate solar energy at sea. It sets out the methodology and findings of the experimental testing conducted within the North Sea Two offshore solar farm project. The paper also offers recommendations for the next steps towards certification, informed by the NS2 project results. With the results and recommendations in the paper, policymakers and industry can take the next steps towards certification, thereby bringing the potential offered by offshore solar energy a step closer to reality.

About Deltares

Deltares is an independent institute for applied research in the field of water and subsurface. Throughout the world, we work on smart solutions, innovations and applications for people, environment and society. Managing densely populated and vulnerable areas is complex, which is why we work closely with governments, businesses, other research institutes, universities and NGO’s at home and abroad.

About TNO

TNO is the largest independent research and technology organization in the Netherlands and one of the largest in the EU. We innovate, investigate, and orchestrate, collaborating closely with governments, universities and the private sector. We inform government on policies and empower evidence-based decision-making through rigorous investigations, cutting-edge scientific insights, and reliable measurements. By building national and international consortia and ecosystems, we drive technological and methodological breakthroughs that help to realise a secure, sustainable, healthy, and digital society, and strengthen the earning power of the Dutch economy. www.tno.nl/en/

About Oceans of Energy

Oceans of Energy is pioneer and world leader in offshore solar. Founded in 2016, the company was established to develop an innovative floating solar foundation capable of withstanding any offshore conditions. In 2019, it installed the world’s first offshore solar farm in high waves, off the coast of The Hague. It proved to the world that offshore solar is a reality, having operated continuously for four years in the rough North Sea – including during more than 10 categorized (winter) storms. In 2023, the first commercial contract for an offshore solar farm was signed with Crosswind, for which the engineering, permitting and fabrication phases were successfully completed, and the offshore installation campaign commenced in April 2025. Oceans of Energy also leads and facilitates a wide range of ecological research to understand the environmental context and actively explores nature-enhancing opportunities. Projects are supported by RVO, MIT-Zuid-Holland, REACT-EU, INTERREG, and Horizon-2020 programs, amongst others. Crosswind is Oceans of Energy’s first commercial type customer.

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For more information:
Oceans of Energy   
Ariane van Hoeken
ariane@oceansofenergy.blue 
+31 6 48 65 09 37

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