Five stories above ground at Colorado State University, a most unlikely garden lies beneath a long row of rooftop solar panels. It’s 9 a.m. in late October, the temperature is 30 degrees Fahrenheit, and the wind is cutting. Shortly before I arrived, researchers had pulled the last hardy crops from the substrate beneath the panels. This was a total of 600 pounds this season. Instead, cool-season produce like arugula, lettuce, kale, Swiss chard and other leafy greens still thrive here, sheltered from the harsh sun.
This is no ordinary green roof, but a vast outdoor laboratory equipped with sensors, overseen by horticulturist Jennifer Bouslow. The idea behind rooftop agrivoltaics is to mimic a forest on top of a building. Just as the shade of towering trees protects undergrowth from sun stress, solar panels can also encourage plant growth. The overall goal is to grow more food for expanding urban populations while conserving water and producing clean energy. and Increase the energy efficiency of buildings.
“If we stop and think about what we need as a society, our building blocks, it’s going to be food, energy and water, as it always has been,” Bouslot says. With a rooftop agricultural power plant, “one of these days he can produce two and save a third, especially in little-used space.”