Floating PV systems may face lower humidity stress than ground-mounted counterparts

A new study looked at whether solar panels floating on lakes and reservoirs suffer more moisture damage than panels mounted on the ground. This matters because moisture that gets into a solar panel over time can degrade it, and floating solar has been assumed to face extra risk from being near water. Researchers led by a team in Norway studied weather and water data from seven lakes in Sweden, Norway, the US, Canada, and New Zealand, then modeled 25 years of moisture buildup in two common panel types.

The findings were not what many expected: panels floating on water did not consistently face worse humidity stress than panels on land. Air and panel temperatures were nearly the same in both settings, and humidity levels near water were sometimes higher, sometimes lower, than on land. In the panel modeling, ground-mounted panels actually picked up more internal moisture on average than floating ones. What mattered more than water versus land was the local climate and how a floating system is built — specifically how high the panels sit above the water and how well the system sheds heat, both of which had a bigger effect on moisture buildup than location itself.

This is research on solar reliability, not a program or rebate, so it does not change anything for homeowners directly. But it is useful background if floating solar for community or utility projects ever comes up near you, since it suggests these systems may not need special treatment simply because they sit over water.