Colorado solar panels increased grassland plant growth by up to 90 percent
Solar panels in Colorado’s drought-stressed grasslands are boosting plant growth by up to 90 percent — and researchers say the drier the land gets, the stronger the effect becomes.
Colorado’s semi-arid grasslands spend much of the summer running a water deficit — the land needs more moisture than the sky delivers, and the grass survives more than it thrives.
Now picture rows of solar panels standing over that parched ground. The image reads like a recipe for making things worse. But four years of field data from an agrivoltaic facility in Longmont, Colorado, have produced results that researchers say they didn’t anticipate at this scale — and that carry real implications for how solar land use is understood in the drought-stressed West.
“This is the first analysis that shows how that pattern becomes more pronounced with increasing aridity or dryness like we see in Colorado,” he said.
A four-year experiment in the Colorado sun
The study comes out of an agrivoltaic solar facility in Longmont, Colorado, where researchers tracked plant and water dynamics over four years. It’s the first field study to measure what actually happens when solar arrays and grasslands share the same ground — not in a greenhouse or a model, but in real semi-arid conditions under genuine drought pressure.
A collaboration between Colorado State University and Cornell University, the work was published in Environmental Research Letters. What makes the findings especially notable is the setup itself. The solar array was designed to maximize energy output — not to help the grass. Nobody optimized the panel angles for shade distribution or configured the system to funnel water toward plant roots. The ecological results emerged anyway.
How panels protect plants from drought
Two mechanisms drive the effect. Partial shading from the panels reduces the heat load and evaporation stress that grasses experience during peak summer months. Water that collects on panel surfaces also drips down to the soil below, improving local moisture in an environment where every drop counts.
The numbers from dry years are striking. Grass growing on the east side of the panels was up to 90% more productive than grass at the open control site during a dry year — not a marginal difference, but a substantial shift in plant output driven entirely by the presence of the infrastructure overhead.
During wet or normal years, the benefit shrinks but doesn’t disappear. The east side of the panels still outperformed the control site. That pattern — stronger gains when conditions are harder — turns out to be the study’s most consequential finding.
The more arid the land, the greater the gain
Previous research had reported improved plant and water relations near solar arrays, but this study goes further. It’s the first field analysis to show that the positive effect becomes more pronounced as conditions grow drier, a pattern researchers call photovoltaic aridity mitigation.
Researcher Matthew Sturchio, a Cornell postdoctoral associate and affiliated researcher at CSU, described why that scaling matters. “This is the first analysis that shows how that pattern becomes more pronounced with increasing aridity or dryness like we see in Colorado,” he said. For the arid western United States, where drought frequency is projected to increase, that relationship has direct practical relevance.
That an unoptimized system produced these results is significant on its own. Sturchio points out that gains could grow with intentional design choices — adjusting panel angle to provide shade when air temperatures spike, or reconfiguring spacing to let more light reach the soil during key parts of the growing season. “With small changes in array design, configuration and management, we may even realize untapped benefits, particularly those related to water use,” he said.
Rethinking solar as an ecosystem tool
Agrivoltaics — co-locating solar infrastructure with agricultural or ecological land uses — is gaining traction as a framework for thinking about solar land differently. Grassland-based systems are particularly low-impact: no irrigation, no heavy machinery, and the potential to support livestock grazing or pollinator habitat alongside energy generation.
CSU University Distinguished Professor Alan Knapp, who has spent decades studying how grasslands cope with chronic water stress, notes that the current study focused on perennial C3 cool-season grasses — plants that prefer wetter conditions. The next phase will examine C4 warm-season grasses, which dominate Colorado’s plains and are adapted to heat and sunlight.
“Those grasslands are even more water-limited than the ones we used in this study,” Knapp said. “Thus, we expect the capability of solar arrays to mitigate water stress may be even greater.” If that hypothesis holds, the implications extend across a much larger portion of the American West. Sturchio also raises the possibility that solar arrays could support grassland restoration by creating pockets of shade, moisture, and varied light conditions where diverse plant communities can establish.
What comes next at the Shortgrass Ecovoltaic Research Facility
The next chapter of this research is already taking shape at the newly constructed Shortgrass Ecovoltaic Research Facility in Nunn, Colorado. Researchers plan to use the site to test whether solar arrays can promote diverse plant communities and support active grassland restoration — moving from observation to intervention.
Climate projections consistently point toward more frequent and more severe droughts across the American West. If solar infrastructure can buffer grasslands against that pressure — even in its current unoptimized form — the land under and around solar arrays becomes a policy question as much as a scientific one. For land managers, energy developers, and conservation planners alike, the dual-use potential is worth watching closely. Early evidence suggests the answer may be yes.
Learn more about this finding here: Matthew A Sturchio, Alan K Knapp. Evidence of photovoltaic aridity mitigation in semi-arid grasslands. Environmental Research Letters, 2025; 20 (6): 064047 DOI: 10.1088/1748-9326/add94d
Daniel García is an Editor-in-Chief with strong expertise in structural work and engineering principles. He combines this technical foundation with deep knowledge of energy, spatial design, and emerging technologies, bringing a forward-thinking and analytical approach to editorial leadership.
