Floating solar photovoltaic energy installations (FPV) are solar panels sitting atop human-made bodies of water. These panels generate renewable energy without taking up space on land. It’s unclear how this floating infrastructure could alter conditions in the water below—an important question to tackle as demand for renewable energy increases.
Small bodies of water could heat up fast as global temperatures rise. Underwater biology may be thrown out of balance, leading to harmful algal blooms and decreased water quality. Ponds absorb heat in urban areas, and if they get warmer, so does the neighborhood. Humans, plants, and animals all stand to lose valuable aquatic resources. In this study, we investigate what happens to the temperature and oxygen content of ponds when covered with floating solar panels.
Project leader and Ph.D. student, Alex Cagle measures water quality at the edge of the floating photovoltaic solar energy array. Collaborator, Sandor “Shawn” Kelly, uses a dip net to study the pond's invertebrates across the environmental gradient created by the floating array. Shawn is the Bug Closet's Collection Manager at the University of Central Florida.
Water temperature and dissolved oxygen were sampled at three FPV study sites in California and Florida.
Water under the FPVs (navy) was cooler than open water sites (teal) in the same pond.
We set out to deploy the first field-based, observational investigation of FPV installations. Led by Alex Cagle, a Ph.D. student, we studied how different pond sizes, climates, and solar panel coverage affects variables like temperature, light and oxygen availability. We combine these data with FPV performance data in collaboration with our project partners.
Installation of floating solar panels across larger areas of water were shown to impact the top meter below the surface. When FPVs covered the majority of the water body, their shading provided a cooling effect in the summer months and created unfavorable conditions for harmful cyanobacteria to grow. We were the first to compare these water quality parameters across multiple small, mixed water bodies.
Cities get hot, along with the shallow ponds in these areas. This makes these bodies of water more sensitive to climate change, especially compared to rural, larger bodies of water, threatening aquatic life below the surface.
Covering shallow lakes and ponds with FPVs may help mitigate increases in water temperature, specifically at the surface level where disproportionate warming occurs. However, too much coverage of these small lakes and ponds can lower levels of dissolved oxygen, posing potentially harmful effects to the vitality of fish and the overall ecosystem.
Why this work matters
Solutions that Benefit Humans and Wildlife
Studying characteristics below the water teaches us how the presence of floating photovoltaic solar energy infrastructure can alter the conditions of ponds and the life they support. Understanding these impacts can help us to create actionable solutions on how solar energy is being deployed on water bodies across the globe.
