This article is based on the key takeaways from the recent Floating Solar in Europe Conference organised by us at Amsterdam, to highlight growth trends, opportunities, technologies, design considerations, O&M issues, investment landscape, challenges, and outlook for the floating solar sector in Europe.

Floating solar has become a popular clean energy solution in many markets across the globe with increasing concerns around acquisition of large tracts of land or unavailability of adequate land in certain regions. A single MW of solar can require up to 4 to 5 acres of land, depending on the technology used. This is a major concern as empty lands are increasingly becoming scarce and expensive. Floating solar projects can prove to be a boon as they do not require land at all and instead can be installed on the surface of water bodies which are otherwise unutilised.

The benefits of these floating solar projects are not limited to conservation of land and efficient utilisation of water reservoirs. Reportedly, they improve solar project efficiency, prevent water evaporation, and reduce algal growth. They also have short gestation periods as they do not require extensive civil works and can have synergies with other collocated renewable energy projects hydropower or offshore wind projects especially for optimum utilisation of transmission infrastructure. Meanwhile, cost economics of these projects is increasingly improving as the floating technology matures and the market expands.

After Asia, such floating solar projects are now rapidly gaining momentum across Europe. Floating solar is already a well-established market in the south of the continent owing to plenty of sunshine that the area receives. Many of these countries, in fact, have supportive policy instruments for floating solar. For instance, Italy simplified its floating solar project permitting process, Spain issued requirements for floating solar projects regarding their coverage on water bodies and water quality, and Portugal held an auction for development of floating solar projects. Meanwhile, the Regulatory Authority for Energy in Greece has licensed 13 floating solar projects in artificial lakes and reservoirs with a total capacity of 839 MW.

Taking lessons from the south, the northern nations are also now witnessing large uptake as they have abundant water bodies. For instance, one of Europe’s biggest floating solar projects has been set up by BayWa r.e. in Sellingen, Netherlands with a capacity of 41.1 MWp. The same company’s subsidiary ECOwind has set up a 24.5 MWp project in Grafenwörth in Lower Austria. Meanwhile, Q Energy France is building a bigger 74 MW floating solar power plant called Les Ilots Blandin in the north-west of France.

Offshore solar is also expected to become a big market in the coming years in the continent with some policy developments already underway. For instance, in the Netherlands, the government’s Nationaal Plan Energiesysteem mentions the possibility of realising 3 GW offshore solar in 2030. In addition, the tender for a 50 MW solar project in IJmuiden Ver Beta offshore wind park in North Sea is also in the pipeline. Meanwhile, Greece has approved the legal framework for the development of pilot floating offshore solar projects.

Project design, execution, and O&M

Typical segmentation of floating solar projects can be done based on location. Commonly, 5-20 MWp projects are set up on small lakes like irrigation or industrial pond, quarry lakes, or small basins. These small lakes often offer simple site conditions for mooring and anchoring. Meanwhile, large lakes like those of dams or water reservoirs can accommodate projects of sizes up to 20-200 MWp. Floating solar projects across all these locations require precise bathymetry data, soil studies and other geotechnical information for accurate project design with innovative mooring systems to help address the complexity of site conditions. Further, when constructed on dam reservoirs, proximity to dam safety equipment, flow velocity and waves also need to be considered at planning stage. In many cases, theory alone might not be sufficient to assess the correct project design and small prototypes might have to be deployed to test site conditions.

Nearshore or offshore floating solar projects can also be set up with very large capacities. Although, small demonstration units have only been set so far in this area, there is significant effort to scale-up this capacity rapidly. For example, Sun’Sète, reportedly, the first offshore solar farm in France and the Mediterranean Sea was inaugurated in March 2023. It is located in open sea conditions with waves going up to 8 meters. Being developed by SolarinBlue, the project is supported by ADEME, TotalEnergies, Engie and Technip Energies, and will reach a capacity of 1 MW by 2025. Another case is that of the floating solar energy test platform installed by SeaVolt in September 2023 in the Belgian North Sea near the Port of Ostend. SeaVolt is a collaboration between Tractebel, DEME, and Jan De Nul.

From an O&M perspective, floating solar projects have additional risks when compared to other solar projects as they require working on water and access can be a major challenge here. Thus, key considerations for proper O&M include easy and stable access to all electrical components. Robotics are already being used in a few projects to inspect and clean the solar panels and mooring systems. 24X7 remote monitoring systems should be used to identify any anomalies beforehand and take corrective action. Ease and safety of O&M should be taken into account at the design stage to minimise opex costs and risks later.

Hybrid projects with floating solar

There are significant benefits in hybridising or blending of various renewable energy sources. As solar generation is intermittent and is available only for a few hours during the day, co-locating it with another energy source ensures more stable generation patterns. Further, it helps in optimum utilisation of space and precious grid infrastructure.

Naturally, hydro power plants that have large water reservoirs are suitable locations for floating solar projects as the existing water surface can be used and various infrastructure can be shared. For instance, in 2022, EDP inaugurated a 5 MW floating solar park in Alqueva pumped storage reservoir in Portugal. The project took seven months for construction and occupies 4 hectares or 0.016 per cent of the total area of the Alqueva Reservoir. The project also has a 1 MW battery system with a storage capacity of around 2 MWh. All these technologies, pumped storage, floating solar and battery, use one single connection point to the existing grid. EDP already has secured a second floating solar farm with 70 MW installed capacity in Alqueva.

As the offshore wind market continues to grow tremendously in Europe, there are many floating solar projects being planned that are co-located with offshore wind to improve generation profile from the combined energy generation of both solar and wind, and also, owing to growing lack of space. Further, offshore floating solar has a non-interfering supply chain with offshore wind which builds the case in favour of co-location. Various small projects are already being set up in different parts of the continent. For example, CrossWind, a joint venture between Shell and Eneco, has awarded a contract to Oceans of Energy for installing and operating offshore solar inside the Hollandse Kust Noord offshore wind park, in the Dutch North Sea, with the solar plant to be realised in 2025. Another project in the pipeline is 500 kW Merganser project being built by RWE and SolarDuck close to an offshore wind farm in the North Sea off the coast of Ostend, Belgium. These two companies have also started work on a 5 MW offshore floating solar project within RWE’s OranjeWind offshore wind farm that is coming up 53 km off the Dutch coast.

Cost considerations

The construction costs of floating solar projects are comparatively higher than ground-based systems as the former require floating platforms and supporting mooring and anchoring along with the solar power project equipment. However, owing to economies of scale, the increasing sizes and scale of projects is expected to bring down the costs of floating solar projects significantly in the coming years. Maturing technology and proven cases are also expected to help lower the capital costs and help improve access to finance.

Currently, the lack of standards makes the due-diligence process quite complicated and the relatively smaller installed capacities of floating solar when compared to other solar technologies means more conservative financing structures to cover risks. However, these financing concerns are expected to improve over the years as cases of successful and profitable projects grow.

On the O&M side, the costs can be higher than traditional solar projects owing to the requirement of specialised services and more stringent safety requirements for carrying out maintenance works in water. Further, in some cases, divers may also be required. Meanwhile, since the projects are on water, many developers would prefer to install robots to do routine inspection and maintenance work which would ultimately help in reducing manpower costs. Thus, the actual O&M costs would depend on a case-to-case basis taking into consideration the location and design of a project.

The way forward

With increasing “Not in my backyard” concerns across Europe and the debate surrounding land utilisation for food-vs-fuel, floating solar projects, both onshore and offshore, are bound to increase in the future. However, to ensure sustainable development of these projects, they should be planned with the right policy interventions in place. Issues like delays for permits and grid connectivity need to be addressed urgently for all renewable energy projects including floating solar.

Going forward, more floating solar projects are expected to come in existing as well as upcoming renewable energy facilities like hydro power plants and offshore wind farms, to optimise costs and infrastructure utilisation. Further, more floating solar projects are expected to be integrated with energy storage systems to ensure reliable generation.