Detailed activity plan for ZoZEP 2026-2029

In the Netherlands, the energy transition increasingly relies on the North Sea for large‑scale renewable energy generation, with offshore wind as a cornerstone and ambitious capacity targets towards 2030 and 2050. To optimise the use of scarce offshore space and improve utilisation of offshore grid infrastructure, additional renewable options are needed to complement offshore wind. Offshore floating photovoltaic systems (OFPV; zon-op-zee) are recognised as a promising addition, but their ecological effects in the marine environment remain uncertain, particularly when deployed at scale and in co-location with offshore wind farms (OWFs). This ecological uncertainty is directly relevant for policy development and permitting under Dutch and European environmental legislation and may otherwise become a bottleneck for responsible decision-making on offshore solar. To address this, the Ministry of Economic Affairs and Climate initiated ZoZEP - the Zon-op-Zee Ecologisch Programma, to identify and address key ecological knowledge gaps on OFPV in a structured and policy-relevant way. The programme’s overarching objective is to generate the ecological knowledge needed to inform Dutch policy and permitting for OFPV within OWFs in the North Sea. ZoZEP is guided by four research questions (RQ) that reflect the main policy needs: RQ1: What are the ecological impacts of OFPV on marine ecosystems? RQ2: What are the cumulative ecological impacts of deploying OFPV within OWF? RQ3: At what deployment scale are ecologically relevant impacts of OFPV expected to occur? RQ4: How does this research translate into practical guidance for policy and permitting? The programme is structured in six work packages that together provide an integrated evidence base for policy and permitting: stakeholder engagement and dissemination (WP1); modelling of hydrodynamics, water quality and lower trophic levels across pilot and North Sea-wide scales (WP2); development and functioning of biofouling communities and related fluxes (WP3); fish distribution, behaviour and how these are affected by OFPV (WP4); birds and bats distribution, behaviour and how these are affected by OFPV (WP5); and synthesis to integrate outcomes into policy relevant conclusions and recommendations (WP6). ZoZEP is executed by a consortium of Deltares and Wageningen Marine Research (WMR) combining expertise in physical processes, biogeochemistry, ecology, offshore monitoring and applied modelling. The programme is developed in close coordination with EZK as commissioning authority and primary policy user, and it actively involves industry partners (e.g., Oceans of Energy, SolarDuck and BlueWater) and a broader stakeholder field through structured engagement. Furthermore, the programme is executed in close cooperation with the parallel research programme KOSO (coordinated by TNO), which focuses on technical and operational risks and costs for utility‑scale offshore solar. A defining feature of ZoZEP is that it is designed to be adaptive, because the offshore demonstrator availability remains uncertain. To date (mid 2026), there are no offshore demonstrators in the North Sea, and the earliest realistic opportunity for offshore monitoring is currently expected in early 2028 within OWF Hollandse Kust West (HKW), with further clarity on timing expected at the end of 2026. ZoZEP therefore proceeds under two scenarios: Plan A (no offshore demonstrator during the programme) and Plan B (an offshore demonstrator becomes available during the programme), with a predefined decision moment at the end of 2026 and a midterm review at the end of 2027 to adjust scope, deliverables and budget allocation in line with the latest developments. ZoZEP’s timeline consists of a completed detailing phase (finalized by mid 2026), an operational phase (mid‑2026 to end‑2028) and a synthesis phase running partly in parallel (early‑2027 to mid‑2029), enabling periodic integration of results rather than postponing synthesis until the end. The programme will deliver technical and scientific outputs (including reports and publications) and, crucially, integrated synthesis products that translate evidence into recommendations for policy, industry and knowledge. In doing so, the programme provides a coherent and