New project on the combination of wind and solar power in the Belgian Marine Zone

The technology for floating photovoltaics has made great progress in recent years. Systems for lakes and reservoirs are meanwhile being rolled out at gigawatt scale worldwide. Several approaches have been developed for offshore use, and first demonstrators are being installed for this innovative technology. Owing to the harsh environment with its strong waves, wind, and risks of corrosion and fouling, this requires an entirely new structural development. Covering an area of less than 10% of a wind farm, PV systems with a nominal power approximately matching that of the wind turbines can be connected sharing the same grid connection, which helps to reduce costs. The exact limits and curtailment losses have to be worked out by detailed analysis. A major beneficial factor is the complementarity of electricity generation between wind and solar throughout the year, as we were able to show in a previous study.

Goals

The goal of the project is to draw up technical guidelines and policy recommendations towards multi-use of commercial zones at sea in so-called “Mariparks”. In this concept, different technologies will be combined taking into account the possible effects of these parks on the marine environment, with effective and efficient integration of electricity generation by offshore wind and photovoltaics playing a key role. The results will be disseminated broadly to serve as a basis for decisions of commercial players and authorities alike.

Approach

The existing concepts for OFPV structures will be analysed with respect to strengths, weaknesses, opportunities and threats, and options for their placement within wind farms and ecological effects will be mapped. The rules for deployment within wind farms need to be refined to consider all requirements for safety distances, environmental constraints, and the concerns of all users. For this, we will consult with stakeholders to work out rules that are safe and effective.

The electrical performance of the PV system will be modelled in detail based on an existing framework for energy yield simulation. The impact of electrical and mechanical layout, marine environment and fast dynamic shading effects will be considered, and long-term degradation will be predicted. Specific measures to ensure reliability of components in harsh offshore conditions will be derived from customized tests. This also concerns the electrical system, where design for reliability and resilience, e.g. by providing redundancies, are key for long-term operation. In a previous ETF project, MarineSPOTS, we already documented that the time complementarity of wind and solar resources allows for better utilization of the grid connection when combining solar power systems of a similar magnitude with wind farms. The detailed limits are determined by the thermal load of cables, and corresponding models will be refined to ensure best scaling while maintaining safe operating conditions.

Apart from the size of the structures, anchoring and mooring design determines to a large extent how the space at sea can best be used by providing proper placement while maintaining safety under all environmental conditions. This is complemented by requirements for safety distances and dedicated spaces for other uses, in particular ship traffic. In addition, when planning structures that add significant exposed surface to the environment, biological effects need to be taken into account to ensure that negative impacts are limited and benign, and possibly identify positive effects. Therefore, models are being worked out for the spatiotemporal distribution of ecological processes that govern the flows and distribution patterns of nutrients and products.

A distinct goal of the project is to draw up policy advice and have an impact on marine spatial planning and permission rules. Therefore, in addition to our own research, a series of workshops will be held where stakeholders from all relevant areas can provide input. The project thus aims to develop guidelines that allow the effective and safe co-use of the marine area dedicated to commercial purposes.

Partners

The project brings together six partners from research, policy and industry.

• Laborelec has broad expertise in renewables and electrical systems and infrastructure, including offshore wind, solar energy, energy storage, power conversion systems and electric cable testing. The Laborelec renewables team has been conducting internal research projects – sponsored by ENGIE Research&Innovation – on offshore wind and floating PV for several years, is responsible for monitoring the OFPV pilot Seavolt and already studied the potential integration of OFPV into a Dutch wind farm.
• With a sustainable blue economy as its core business, Blue Cluster has built up considerable expertise in (international) marine policy and gives advice to policy makers based on the experience of innovative technologies in its projects. They are involved in various innovative projects dealing with multi-use of marine spaces as well as Marine Spatial Planning, and provide a strong link to the business community.
• RBINS possesses significant expertise in marine ecology, covering hydrodynamic and biogeochemical modelling, experimental work, and field studies. This positions them well for the quantification of environmental impacts related to OFPV, and anthropogenic activity at seas more generally. The competencies on these topics were established in several previous research projects.
• Imec/EnergyVille runs and develops a physics-based energy yield modelling framework allowing to calculate the energy yield of several integrated-PV applications as a function of environmental conditions and installation constraints. By extending a model established in the MarineSPOTS project, the energy system will build further on degradation models for PV systems under different stressors, which can be refined with the unique environment of OFPV.
• UHasselt/EnergyVille has broad expertise in the domain of energy systems reliability within the research institute imo-imomec, in collaboration with imec. In previous projects, the imo-imomec researchers worked on reliability modelling and testing of solar modules and power electronic systems under different thermal, mechanical and electrical stresses, as well as PV system design, in-situ sensing and energy optimisation.
• On top of existing broad know-how in marine structural design, KU Leuven/EnergyVille has gained significant expertise in OFPV over the past two years, not least through the MarineSPOTS ETF project. The electrical backbone of renewable energy systems, both in terms of power electronic converters and power system integration, forms part of their background, as  do grid design and market aspects.

The project will be guided by an Advisory Board with ten members from industry active in the marine space and renewable energies.

“With the complementary expertise of the partners, we will determine the boundary conditions for the integration of solar and wind energy offshore. We will engage with stakeholders to work out pathways for effective deployment of this exciting combination of technologies. This can help to put Belgium firmly on the map when it comes to innovative renewable energy generation.”, says Johan Driesen, Professor of Electrical Engineering at KU Leuven and affiliated with EnergyVille.