Ecological impacts of floating photovoltaics on lake ecosystems: eco-design and research perspectives

Floating photovoltaic (FPV) systems are expanding rapidly. While they could be a solution to land-use conflicts in renewable energy development, their ecological impacts remain poorly understood. A national seminar held in France in June 2025 gathered scientists, public authorities, NGOs, and industry stakeholders to assess FPV deployment potential, ecological risks, and eco-design strategies. This seminar was organized by the French Renewable Energies and Biodiversity Observatory, which aims to reconcile energy transition with biodiversity conservation through knowledge sharing and co-elaboration of technical guidelines. Although the effects of FPV systems on some physical parameters ( e.g. , light, temperature) have been demonstrated, the consequence on biological process needs to be better understood. Standardized Before-After-Control-Impact (BACI) protocols and long-term monitoring should be prioritized. Integrated quantification of the impacts should be also developed, notably through monitoring of the different trophic levels and of functional indicators ( e.g. , gas and energy exchanges). Future research projects should then promote interdisciplinary collaborations. In the meantime, FPV projects are developing and guidelines for their eco-design are expected. To this end, the participants reviewed a draft eco-design guide proposing a step-by-step framework: i) site selection and project size, ii) platform design, iii) ecosystem design, and iv) park management. All the stakeholders emphasized the need for early-stage guidance ( e.g. , choice of the sites) and for scientific-based recommendations supported by real-world examples. They supported the development of a shared and evolving reference document that facilitates dialogue among stakeholder groups.