Floating-PV, or photovoltaic systems on water surfaces, has gained significance worldwide in recent years. This innovative technology uses bodies of water, such as reservoirs, gravel pits, or water storage basins, to generate electricity without occupying valuable land. In Germany, where expanding renewable energy with limited land resources presents a challenge, Floating-PV holds great potential. A detailed look at the technology, challenges, and approval processes shows how Floating-PV can support the energy transition.
Development of Floating-PV: Early Installations and Technical Progress
The first Floating-PV systems were installed in Japan in 2007, where land is scarce and energy demand is high. Since then, technologies and installation methods have rapidly advanced. In China and the Netherlands, some of the world’s largest floating solar systems have been built, demonstrating the technology’s market maturity. In Europe, Floating-PV installations have grown popular in countries like France and the Netherlands since the mid-2010s. The Floating-PV market in Germany started a bit later, but there are now several pilot projects, particularly on gravel pits in the southern regions.
Technical Features of Floating-PV
Floating-PV presents technical challenges that differ significantly from conventional ground-mounted systems. The main focus is on the modules, floating platforms, and the specific requirements for cabling and anchoring.
Modules and Corrosion Protection
Floating-PV systems use specially developed PV modules that must withstand harsh water conditions. These modules offer special protection against corrosion caused by moisture and salts, particularly in coastal or mineral-rich waters. Frameless glass-glass modules are often used because they are less prone to corrosion. Additionally, bifacial modules, which can capture both direct and reflected light, are especially suitable for Floating-PV, as they can increase yield by up to 20%.
Floating Platforms and Anchoring Systems
The modules are installed on floating platforms made from high-density polyethylene (HDPE) or other UV-resistant and corrosion-resistant materials. These platforms are modular and can be adjusted to fit the size of the water body. The system is anchored using cables or weight-based anchors, chosen based on water depth and bottom conditions. Stable anchoring is crucial to protect the system from wind, waves, and currents.
Cabling and Energy Transmission
Cabling is a significant technical challenge in Floating-PV systems. Waterproof, flexible cables must accommodate the movement of the floating structure and resist mechanical stress and UV radiation. In many projects, substations are also installed floating on the water surface to minimize energy transmission losses.
Floating-PV in Germany: Potential and Challenges
Germany, with its numerous gravel pits, reservoirs, and former mining lakes, offers enormous potential for Floating-PV systems. In water-rich regions like Bavaria and North Rhine-Westphalia, large areas could be used for energy generation without encroaching on agricultural or built-up land.
Use of Gravel Pits and Former Mining Lakes
Germany has more than 30,000 gravel pits, often used for industrial or recreational purposes. These artificially created water bodies provide ideal conditions for Floating-PV due to good grid connections and stable water levels. In former mining regions such as Lusatia or the Rhenish coal district, Floating-PV systems could play a key role in the transition to renewable energy.
Reservoirs and Water Storage as Synergy Potentials
Reservoirs already used for hydropower also offer significant potential for Floating-PV. Combining hydropower with solar energy could create hybrid power plants that ensure reliable energy supply, especially during times of low sunlight.
Approval Procedures for Floating-PV in Germany
Installing Floating-PV systems in Germany is subject to specific legal requirements that can vary depending on the location and type of water body. The regulatory process is complex, covering environmental and water management aspects.
Construction and Environmental Regulations
Floating-PV systems are typically installed on still bodies of water, such as gravel pits or reservoirs, requiring a building permit under state building codes. These requirements can differ between federal states. In addition to building regulations, water management requirements must also be met, particularly regarding water quality and local ecosystem protection.
Environmental Impact Assessment (EIA)
An Environmental Impact Assessment (EIA) is usually required if a Floating-PV system exceeds a certain size or is planned in an ecologically sensitive area. This assessment evaluates the system’s potential effects on the water ecosystem, particularly on fauna, flora, and water quality. In many cases, specific measures are necessary to minimize negative environmental impacts. In particularly sensitive waters, such as artificial gravel pits, an EIA may be required even for smaller areas (e.g., 1 to 5 hectares).
Special Regulations for Artificial Water Bodies
Artificial bodies of water like gravel pits or former mining lakes generally have simplified approval procedures because these waters typically do not contain protected ecological systems. The approval process is less complex, allowing for faster project implementation.
Incentive Programs and Funding
Under the Renewable Energy Sources Act (EEG), Floating-PV systems are generally eligible for subsidies. There are additional financial incentives for innovative projects installed on artificial bodies of water, helping offset the higher installation costs compared to ground-mounted systems.
C2sun Experts' Conclusion: Floating-PV as a Key Technology for Germany
Floating-PV offers a sustainable way to harness the potential of unused water surfaces in Germany while reducing reliance on land for energy generation. Despite higher installation costs and regulatory challenges, Germany’s numerous gravel pits, reservoirs, and former mining lakes present significant potential for widespread use of this technology. With careful technical planning, robust and corrosion-resistant modules, and strong support through the EEG, Floating-PV could make a substantial contribution to Germany’s energy transition in the coming years.