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

The SWiM (Solar and Wind in the Belgian Marine Zone) project, funded by the Belgian Energy Transition Funds, brings together six partners from industry and science. They will conduct research into the combination of marine technologies in Belgium’s Exclusive Economic Zone, in particular to integrate Offshore Floating Photovoltaics (OFPV) into wind farms in an ecologically sustainable way.

Owing to the harsh environment with its 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 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.

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.

Our partners

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

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

KU Leuven – EnergyVille

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.

Engie Laborelec

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.

Blue Cluster

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.

The Institute of Natural Sciences

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

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

UHasselt/EnergyVille has broad expertise in the domain of energy systems reliability within the department imo-imomec, in collaboration with imec. In previous projects, this research group 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.

Linking business and policy

In a new project, SWiM – Solar and Wind in the Belgian Marine Zone, funded by the Belgian Energy Transition Funds, six partners are joining forces. They will conduct research on the combination of marine technologies in the Exclusive Economic Zone of Belgium, in particular to integrate Offshore Floating Photovoltaics (OFPV) into wind farms in an ecologically sustainable way.

Work Package 0

Project management

This work package deals with tracking the timing of the tasks, conducting risk assessments, calling for remediation in case of major deviations and monitoring the budget.

This includes organising regular meetings, exchanging information with the Advisory Committee, summarising the results in internal reports and disclosing information to the public.

Work Package 1

Energy yield and reliability assesment

The deployment of energy systems at sea, particularly offshore photovoltaic (OFPV) installations, presents many challenges that significantly impact energy yield and system reliability. One of the foremost challenges is the dynamic and harsh marine environment, subjecting the OFPV systems to wave-induced movements, salt deposition, algae growth, and bird droppings.

These factors affect energy generation and reliability of the FPV system. Additionally, the presence of nearby wind turbines introduces dynamic shading effects, influencing the overall performance of PV modules and the power conversion system.

Work Package 2

Electrical design and grid integration

Our researchers have shown good complementarity between solar and wind resources around the year. Combining wind farms and PV systems makes it possible to increase the use of the cable connecting the system to the shore, which represents a significant share of the investment costs. In Work Package 2, the limitations of the cable will be analysed in detail to determine which amount of electricity can be brought onshore, and to ensure proper sizing of the PV generator while keeping curtailment losses in check.

The true limitation depends on the thermal properties of the cable and its surroundings. A detailed model is necessary to determine the time-temperature behavior and to stay within safe limits. Other ways to overcome cable constraints are battery storage or conversion to hydrogen. Concepts will be investigated to determine their technical and economic feasibility. The results of the study will be applied to representative model cases. Further work will be done on the internal electrical design of the PV system, considering options for direct current and alternating current designs.

Work Package 3

Structures and mooring

To successfully implement large-scale OFPV projects in Belgian waters, a significant augmentation in the density of offshore infrastructures is imperative. This, however, introduces challenges related to maintaining the necessary safety distances between floating structures and anchoring systems. It is therefore paramount to optimise the number, size, and positioning of OFPVs within an OWP, considering practical spatial constraints, to ensure optimal energy generation from OFPV parks.

An important objective is to explore the most efficient integration of OFPVs and OWPs. Utilizing the vacant spaces between wind turbines for OFPV installation holds promise for achieving higher capacity density, potentially up to seven times the typical values for standalone wind turbines. This strategic placement can lead to increased and smoother power output, decreased environmental loads attributable to park effects, and shared infrastructure for grid connectivity and operation and maintenance (O&M) activities.

Work Package 4

Environmental aspects

The deployment of OFPV in Belgian waters will amount to a substantial increase in offshore infrastructures with regard to to the current offshore wind farm setting, and in particular a tremendous increase in submerged surfaces and anchoring systems. Submerged structures in the sea are rapidly colonised by hard-substrate organisms, which filter large volumes of water and excrete fecal pellets rich in organic carbon.

The effect of OFPV installations on the marine environment consists of a change in the intensity and the spatio-temporal distribution of ecological processes that determine the flows and distribution patterns of chemical elements from coast to offshore and from water surface to the seabed in the Belgian part of the North Sea. Scaling-up those effects at a regional scale requires inclusion of fouling fauna process rates within a realistic representation of the background environmental dynamics.

Work Package 5

Policies, link to the business ecosystem, dissemination and communication

Sustainable Blue Economy depends on innovation and efficient use of space (co-location or multi-use). Integrating floating PV in existing offshore wind farms is a tangible example of potential implementation of multi-use of space and accelerating the development of Sustainable Blue Economy.

It implies that permitting procedures have to accommodate for combined use. This specific case provides the opportunity for policy analysis and to produce recommendations on necessary changes in the existing permitting procedures.