The global expansion of renewable energy is leading to the increased use of floating solar panels, which are now being deployed in marine environments. While this technology offers a promising way to generate clean energy without competing for land, new research is revealing its potential downsides for the ecosystems beneath the waves. The presence of these large floating structures can introduce a range of stressors to the seafloor, from blocking essential sunlight to physically disturbing the seabed, raising concerns about the long-term health of marine life.
A growing body of scientific inquiry indicates that the impacts of floating solar arrays are multifaceted, affecting hydrodynamics, light availability, and the composition of marine communities. The mooring systems required to anchor these panels can physically damage the seafloor, while the panels themselves create extensive shading that alters the conditions for organisms living below. These effects can lead to significant changes in local biodiversity and ecosystem function, prompting researchers and engineers to seek solutions that mitigate these newly identified environmental pressures.
Shading effects on benthic life
One of the most direct impacts of floating solar panels on the marine environment is the shading of the water column and the seafloor. This reduction in sunlight can have significant consequences for photosynthetic organisms, such as seagrass and corals, which depend on light for their survival. In coastal areas where these species are prevalent, the presence of large-scale floating solar arrays could inhibit their growth and even lead to their decline, affecting the many other species that rely on these habitats for food and shelter.
The extent of the impact of shading depends on several factors, including the size of the gaps between the solar panels and the overall scale of the installation. Continuous, dense arrays of panels will have a more pronounced effect than those with more space for sunlight to penetrate. Researchers are still studying the cascading effects of this light reduction through the food web, but it is clear that altering the fundamental availability of light energy will have consequences for the entire local ecosystem.
Physical disturbance from mooring systems
To keep floating solar panels in place, extensive mooring systems are required, and these can be a major source of stress on the seafloor. The movement of the floating structures with the wind and waves can cause the mooring cables to drag along the seabed, a process known as scouring. This is particularly damaging in sensitive habitats like seagrass beds, where the cables can uproot plants and disturb the sediment.
This physical disturbance not only affects the organisms living on the seafloor but can also release carbon that is stored in the sediments, potentially contributing to greenhouse gas emissions. The design of these mooring systems is therefore a critical factor in mitigating their environmental impact. Careful planning and the use of appropriate technologies can help to minimize contact with the seabed and reduce the overall physical footprint of the solar installation.
Alterations to local biodiversity
The introduction of any new structure into a marine environment will inevitably alter the local biodiversity, and floating solar panels are no exception. The panels and their associated infrastructure, such as anchors and cables, can act as artificial reefs, providing new hard surfaces for organisms like mussels and oysters to settle on. This can attract fish and other mobile species, creating a new, localized ecosystem around the installation.
However, this change is not always positive. The new habitats created by the solar arrays may favor species that are not native to the area, potentially leading to the displacement of the original inhabitants of the soft-sediment seafloor. There is also the risk of introducing invasive species that can outcompete native organisms and disrupt the existing ecological balance. The long-term consequences of these changes to biodiversity are still being studied, but it is clear that the introduction of floating solar panels can lead to a significant restructuring of marine communities.
Indirect ecosystem-wide consequences
Beyond the direct impacts of shading and physical disturbance, floating solar panels can also have a range of indirect effects on the marine environment. The presence of the large floating structures can alter local hydrodynamics, affecting water flow and circulation patterns. This can, in turn, influence the transport of nutrients and sediments, with potential knock-on effects for both the water column and the seafloor. The panels can also affect the exchange of energy between the water and the atmosphere, leading to changes in water temperature.
Electromagnetic fields and other energy emissions
The underwater cables used to transmit the electricity generated by the solar panels can emit electromagnetic fields (EMF), which may have an impact on marine organisms. While the effects of EMF are still not fully understood, some studies suggest that they can affect the behavior and development of certain species. In addition to EMF, the operation of the solar arrays may also produce underwater sound, which could disturb marine mammals and other animals that rely on sound for communication and navigation. Further research is needed to fully assess the risks posed by these energy emissions and to develop strategies to mitigate any potential harm.