Solar panel arrays may help sustain grasslands during drought: Study

The placement of solar panels in Colorado’s grasslands could help decrease water stress and increase plant growth by about 20 percent during dry years, a new study has found.

In these semi-arid areas, where grasslands often don’t get as much water as they need, the partial shading offered by solar systems can help plants get through harsh summers, according to the study, published in Environmental Research Letters.

The plants also benefit from any additional water that ends up collecting on the panels, the authors noted.

“Even though this solar array was designed to maximize energy generation — not to promote beneficial environmental conditions for the grasses grown beneath — it still provided a more favorable environment during a dry year,” lead author Matthew Sturchio, a postdoctoral researcher at Cornell University, said in a statement.

In more temperate environments, although solar power arrays provide a critical source of renewable energy, they also reduce the availability of sunlight for plant growth. The diminished presence of local vegetation also means a decrease in plant-based carbon storage and the forage available for grazing animals. 

But during dry years in semi-arid Colorado, scientists found that grass growth on the east side of panels was in some cases considerably more productive than in adjacent open sites.

In wet and normal years, the positive rate of production was reduced, but the east side of the panels still saw more grass growth than the neighboring control spots.

The scientists suggested maximizing potential gains by adjusting panel arrays to changing environmental conditions — such as repositioning them to provide shade when air temperatures rise or configuring them to let in more light during growing seasons.

“With small changes in array design, configuration and management, we may even realize untapped benefits, particularly those related to water use,” Sturchio said.

Going forward, Sturchio and senior author Alan Knapp, a biology professor at Colorado State University, said they are researching optimal ways to place solar power infrastructure in order to also support grazing livestock or habitat pollinators. 

“PV solar arrays may provide a unique opportunity to harvest the sun for electrical energy, reduce greenhouse gas emissions and mitigate the climate change threat of increased water limitation to ecosystem functioning,” the authors concluded.