Large-scale solar can cool nearby areas

An international team of scientists observed a cooling effect in a large radius around solar arrays. The cooling may have implications for local ecosystem management.

Scientists from the University of California-Davis, Lancaster University, and Ludong University in China published research showing that utility-scale solar facilities can have a cooling effect not only on the land covered by the array, but also in the surrounding area.

Solar facilities were found to produce “cool islands” that extend up to 700 meters from the boundaries of the arrays. Land surface temperature was reduced by up to 2.3 degrees Celsius (3.6 Fahrenheit) at 100 meters away; the cooling effects tapered off exponentially to 700 meters.

Studies of two solar parks–the 300 MW Stateline project in California and the 850 MW Longyangxia project in China–were conducted using Landsat satellite images, an approach the researchers said had not previously been applied to solar. The study team compared land surface temperatures around solar facilities before and after they were built. The Stateline solar park measurements were supplemented with ground-collected data.

The researchers hypothesized that the cooling was caused by a combination of shading and insulating the land surface, and by the direct conversion of energy into electricity by the solar panels.

The study authors concluded the effect could have impact on local ecological processes. Productivity, decomposition, and ultimately the carbon balance could be skewed by the cooling. The scale of effect depends on location, and impacts could range from positive, negative, or inconsequential based on local ecosystems.

For example, in California’s Mojave Desert, lower surface temperatures leads to reduced germination rates and a loss of biodiversity. But, in the Tibetan Plateau, lower surface temperatures could potentially reduce the amount of methane lost to the atmosphere, said the scientists.

“This heightens the importance of understanding the implications of renewable energy technologies on the hosting landscape – we need to ensure that the energy transition does not cause undue damage to ecological systems and ideally has net positive consequences on the places where we build them,” said the research, which was published in Renewable and Sustainable Energy Transition.

The studies were conducted in arid locations. The researchers said that further study is needed to determine the effect in more temperate climates.

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