Recent Southern Oregon University graduate Sai Weiss has shown solar panels and crops can co-exist on the same land — and that the combination can even boost the productivity of shade-loving plants such as lettuce.
The results could have far-reaching implications for the emerging practice of solar double-cropping, in which farmers raise plants amid solar panels that allow some sunlight to reach the ground.
California-based SolAgra Corp., which specializes in farm and energy projects, tapped Weiss to carry out scientific research while he was still a student at SOU.
Weiss, 22, graduated earlier this month with a major in environmental studies and a minor in economics. His goal is to help develop sustainable practices that are economically viable in the marketplace.
"I'm passionate about the idea of growing food under solar panels," Weiss said.
To carry out his experiment on crops and solar panels, Weiss grew four groups of lettuce inside a plywood structure near SOU's new Center for Sustainability organic farm along Walker Avenue in Ashland.
One batch of lettuce grew under full sunlight, while other batches grew under 52 percent shade, 61 percent shade and 69 percent shade. The shaded lettuce was planted under plywood panels with slits to replicate the partial shading created by various solar panel designs.
The lettuce growing under 52 percent shade had the highest yield, beating out the lettuce grown under full sunlight, Weiss said.
"The hardest thing about generating solar power on farmland is to figure out how to maximize the area of solar panels and minimize the effects on the plant life underneath," he said.
With conventional agriculture, lettuce is grown in fields under full sunlight. But farmers could boost crop yields while also generating solar power by installing solar panels above their land, Weiss said.
SolAgra has designed systems in which solar panels are mounted high enough above the ground to allow tractors and other equipment to travel below.
Until recently, it was assumed any sunshine used for solar production was sunshine taken away from crops. But research is showing some crop yields can be enhanced with the right solar array, according to SolAgra.
As an added bonus, partially shading crops with solar panels reduces plants' exposure to the hottest midday rays of the sun, cutting the amount of irrigation water needed, according to the company.
Weiss said reducing water demand is especially important for areas facing drought.
Weiss, who was paid by SolAgra to carry out the study, said he was proud to bring research dollars to SOU.
SolAgra is working with researchers at other universities as well, including the University of California, Davis.
With SOU facing budget difficulties and cuts to faculty and programs, Weiss said research dollars could help sustain the university financially.
"I hope more students will be able to bring more research to the university. Research can be the new building block for the university," he said.