by Blaine Howerton | North Forty News
New research shows solar arrays can reduce drought stress and boost grassland productivity during dry years, offering a path to cleaner energy with fewer ecological tradeoffs.
Colorado’s short-grass prairies are landscapes shaped by scarcity—especially water. As climate change intensifies drought across the Front Range and eastern plains, scientists are rethinking how land can serve multiple purposes at once. New research suggests that solar energy development, when undertaken thoughtfully, may not only coexist with grasslands but also help them endure.
At the center of this work is Alan Knapp, a University Distinguished Professor in the Department of Biology at Colorado State University. Knapp has spent decades studying grasslands worldwide—from the Great Plains and Wyoming to South Africa and Inner Mongolia—seeking to understand how plants respond to water, light, temperature, grazing, and fire.
That long view now informs some of the most applied work of his career.
“There’s a lot of the landscape in Colorado that’s going to be altered pretty dramatically with solar panels,” Knapp said during a recent interview at CSU’s Semi-Arid Grassland Research Center. “But if we’re smart about it, once we know what’s happening, can we modify solar arrays to make them better and more compatible with our ecosystems?”
Testing solar’s impact on grasslands
Knapp and Matthew Sturchio led a four-year field study at Jack’s Solar Garden near Longmont, an agrivoltaics research facility built over semi-arid grassland. Their findings were published in Environmental Research Letters and represent one of the first direct field tests of the aridity-mitigation potential of photovoltaic solar arrays.
Grassland productivity—measured as aboveground net primary production, or forage growth—is overwhelmingly controlled by water availability. Over the four years of the study, precipitation varied nearly twofold, ranging from a historically wet year to a significantly dry year.
In dry years, solar panels changed the equation.
Researchers found that overall grassland productivity within the solar array was about 20% higher than in adjacent open grassland. In some locations—particularly near panel edges—plant growth was up to 90% higher than in areas without solar coverage.
The reason lies in the microclimates created by single-axis tracking panels. Morning shade lowers air temperatures and reduces evaporative demand. Afternoon rain, which dominates Colorado’s precipitation patterns, is redistributed by panels across the soil surface. Together, these factors reduce plant water stress during the most challenging conditions.
“This is the first study I’ve actually done in my career that is so directly focused on an applied issue,” Knapp said. “Where I’ve said, ‘OK, these novel manmade structures are going to be installed in native ecosystems — how are they affecting the plants beneath?’ Light. Water. Temperature. All the sorts of things that we’ve studied historically in a more fundamental sense.”
Not a universal benefit—by design
The benefits were not consistent from year to year. In average precipitation years, improved water conditions largely offset reduced sunlight, resulting in productivity comparable to that of open grassland. In very wet years, shading from panels slightly reduced total grass growth.
That variability matters. From a land-management perspective, the researchers note that increased forage during drought—when grass is most scarce and valuable—may outweigh modest losses during wet years.
“What if drought happens?” Knapp said while describing the broader purpose of the work. “What can we expect to happen to forage production or how communities of plants are likely to change? We can use this knowledge to make informed guesses about how the world might be different in the future.”
A shift toward ecovoltaics
This research falls under an emerging framework known as ecovoltaics—the application of ecological principles to solar design and operation. Rather than treating ecosystems as passive ground beneath energy infrastructure, ecovoltaics seeks to co-prioritize energy production and ecosystem services.
Knapp’s interest in renewable energy stretches back decades. “My senior undergraduate project in a natural resources class was on alternative energy sources,” he said. “So, I’ve always had this interest in renewable energy.”
That interest was further heightened while driving past large solar installations near Denver International Airport.
“I saw all these solar panels and began thinking, ‘Those probably have a big effect on water availability in the ecosystem,’” Knapp said. “Because when an ecosystem is shaded, it loses less water.”
The study suggests future solar arrays could be intentionally designed to enhance those benefits through panel height, spacing, orientation, or even modified tracking behavior that sometimes prioritizes plant health over maximum energy output during extreme heat and drought.
Implications for Colorado
Colorado has set ambitious renewable energy targets, and utility-scale solar will be essential to meeting them. Semi-arid grasslands are often prime locations for development due to flat terrain and abundant sunlight—but concerns about habitat loss and land conversion remain.
This research reframes that conversation. Rather than viewing solar development and grassland conservation as competing goals, ecovoltaics suggests a potential alignment—especially in a future defined by increasing aridity.
“That’s why we’re here in this field,” Knapp said, gesturing across the research plots beneath the panels. The work, he explained, is about understanding ecosystems well enough to make better decisions—for land, for energy, and for the people who depend on both.
With careful planning and science-driven design, Colorado’s grasslands may help power the state’s clean energy transition—while remaining productive, resilient, and alive beneath the panels above.
Attribution: Portions of this reporting are informed by interviews and background material by Taryn Bradley, Source, Colorado State University.
