Solar panels can change the water beneath them — and that’s just the start.
Scientists began trying to find out what would happen if large parts of a lake surface became covered by floating solar panel systems.
Very little was known about how those installations might affect the water below.
This was due to more than just the sun shining down on the water.
Almost 3 full years of monitoring took place at one of the world’s largest floating solar parks located on a sand extraction lake in Oudehaske, Netherlands.
These conclusions came from a larger research project aimed at understanding the impact of floating solar on aquatic ecosystems.
As floating solar is now being installed on lakes and reservoirs worldwide, questions regarding its influence on aquatic ecosystems have become more relevant.
How floating solar affects a lake
There are some benefits to using floating solar.
The use of floating solar greatly reduces the amount of land required for a solar array.
There are also areas where floating solar provides shade over bodies of water.
Therefore, determining the implications of this additional shading for the lake below the solar panels is the primary goal.
A model was developed using field data from the floating solar installation.
What happened beneath the panels
It combined information on primary production, light availability, and water temperature to determine how these factors affected the aquatic system.
One factor received particular attention.
When a section of a lake becomes shaded by floating solar panels, less light enters the water below.
To gain further insight into how much light actually penetrated through the water under floating solar panels, almost three years’ worth of monitoring data were collected at the floating solar location.
The analysis indicated significant variations existed in the water quality beneath the floating solar installation.
Concentrations of dissolved oxygen were notably lower beneath the floating solar arrays.
Primary production in the top layer of water exhibited a marked decrease.
These results demonstrated that alterations occurring near the surface impacted conditions in deeper layers of the lake.
Why primary production matters
While there were notable changes in light penetration associated with floating solar, other concerns emerged from monitoring efforts.
Dissolved oxygen levels are often used as an indicator of aquatic ecosystem health.
Primary production is another important measure.
As highlighted by ASLO, it supports zooplankton, nutrient cycling, and higher levels of the food web.
As a result, declines in primary production can affect much more than the organisms producing it.
Understanding the scale of those effects requires long-term monitoring.
Previous studies concerning floating solar systems have typically examined physical variables or monitored lake conditions over relatively short durations.
Observations taken over longer durations provide insights into changes occurring in aquatic ecosystems during multiple seasons.
Monitoring programs conducted in Oudehaske lasted over multiple years as opposed to focusing on seasonal trends.
Deltares found that combining long-term monitoring with modeling revealed patterns that may have been missed during shorter studies.
What the findings could mean for future projects
With many countries actively developing floating solar technology, the number of inquiries about environmental impacts is increasing accordingly.
These findings do not imply that all floating solar projects will produce similar results.
They do illustrate why continuous ecological monitoring is necessary.
One of the clearest conclusions was the importance of conducting multi-year monitoring programs and collecting baseline data before and after installation.
A combination of modeling techniques with field-based observations was used to estimate light penetration and assess water quality at the floating solar installation.
Through such combinations of modeling and monitoring, it became possible to move past simple assumptions in addressing changes related to floating solar.
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