A recently published study in Scientific Reports found that nighttime temperatures over a solar photovoltaic (PV) power plant were regularly three to four degrees Centigrade higher than wildland temperatures. The finding is a direct contrast to other studies based on models that suggests solar PV systems should lower ambient temperatures.
The lead author of the study, Greg Barron-Gafford of the University of Arizona, told ResearchGate that the investigators wanted find out if there were any unintended side effects to renewable energy production after hearing of concerns from nearby residents.
In an interview Barron-Gifford explained what the researchers believe is happening:
We believe that this heat island effect results from the transition in how solar energy moves in and out of a photovoltaic installation versus a natural ecosystem. Basically, there are two ways to “get rid” of heat from solar energy in an environment: latent heat (for example when water transforms from liquid to vapor) or sensible heat (the heat you can feel). When one pathway is reduced, you have an increase in the other.
When asked if there might be instances where temperature difference would indicate a reason not to build a solar PV plant, Barron-Gifford replied:
So far, we have not identified a reason to support any hesitation in future solar power plant development. Our preliminary work suggests that the reach of the heat island effect is too small for a solar power plant to affect local homes. We should, though, consider the fact that solar panels become less efficient as they warm, so in a way, the heat island effect could actually be negatively impacting their production. I see this as encouragement to investigate mitigation potentials more than a cause for moving away from solar.