A new study conducted by researchers at Oregon State University (OSU) and the U.S. Geological Survey claims the environmental impact of floating solar projects has not fully been considered on U.S. installations.
D3Energy and Ameresco built Utah’s first floating solar project on a retention pond atop a mountain. D3Energy
The study published this month, “Modeling diverse environmental responses of reservoirs to floating photovoltaic systems,” analyzed 11 floating solar projects built in Arkansas, Idaho, Oregon, Ohio, Tennessee and Washington. Researchers found that the floating arrays all lowered temperatures in each body of water, according to a press release, but that effect has differing implications for sustaining or harming aquatic habitats.
“Different reservoirs are going to respond differently based on factors like depth, circulation dynamics and the fish species that are important for management,” said Evan Bredeweg, lead author of the study and a former postdoctoral scholar at Oregon State, in a press release. “There’s no one-size-fits-all formula for designing these systems. It’s ecology — it’s messy.”
Floating solar touts the benefits of reducing land use for construction. There’s no civil work, save for anchoring into the bottom or shoreline of a reservoir. Plus these arrays have a smaller project footprint than ground-mounted arrays of a similar size.
“When you think about it, you have this nice flat surface already,” said David Goldenberg, project development engineer for Ameresco, in a solar project case study published in January. “You don’t have to do all this civil work. Like on a ground-mount, we would have to move a lot of dirt around to flatten it.”
By keeping panels over water, these arrays lower temperatures from shading, which reduces evaporation and cools solar modules, making them more efficient. It also curbs algal activity found in warmer waters.
In January, the U.S. Department of Energy National Renewable Energy Laboratory published a study claiming that floating solar built on federal and regulated reservoirs in the U.S. could produce enough energy to power about 100 million homes.
However, the OSU study implores that more focus must be placed on the impacts floating solar projects have on ecosystems. And the NREL study acknowledges that it does not consider how animal activity could affect floating solar development. Introducing artificially-made temperature changes into bodies of water can affect fish habitats. OSU researchers recommended that floating solar projects should be designed to best fit the needs of each reservoir and its ecosystem.
“History has shown that large-scale modifications to freshwater ecosystems, such as hydroelectric dams, can have unforeseen and lasting consequences,” Bredeweg said.
