Scientists from the French Universities, University of Toulouse and Claude Bernard University Lyon 1 have conducted a three-year study on floating photovoltaics (FPVs) in freshwater lakes. Using a Before-After-Control-Impact (BACI) framework, they analyzed three FPV-covered lakes and three non-FPV lakes to assess temperature variations. The study found that FPVs reduced annual water temperatures by 1.2°C on average, with reductions reaching 3°C during the hottest days in spring and summer. The cooling effect extended beyond FPV-covered areas, influencing entire lakes. While lower summer temperatures may benefit aquatic organisms, concerns include decreased dissolved oxygen level, disruptions in the carbon cycles and greenhouse gas emissions. The study, published in the Journal of Environmental Management, underscores the need for continued investigation on FPVs' ecological impact.