UC Riverside is building a greenhouse with a translucent roof that generates solar power while allowing sunlight to pass through to plants below.
The greenhouse will serve as a laboratory to probe the solar energy production, plant growth and costs of growing food in such systems, said Jeff Kaplan, a UCR associate vice chancellor.
“We see this as a strategy to use land for solar energy while simultaneously using it for agriculture,” said Kaplan, who oversees UCR’s sustainability programs.
The technology, developed at UC Santa Cruz, could potentially help usher in an era when greenhouses can produce food with no need for outside electricity to power fans or lights.
The solar panels at UCR will charge a battery in the 800-square foot greenhouse. The goal is for the system to make and store all the electricity the building needs without a connection to the campus electricity network. The construction budget is $174,000 with about $15,000 of that going for the panels, added Scott Donnell, a UCR project manager.
The university expects the greenhouse to be constructed in about two months, Donnell said. The researchers have yet to be named.
By controlling climate, water use and plant nutrition, greenhouses can produce food using a fraction of the land and water when compared with traditional field agriculture, said Glenn Alers, president of Soliculture, the startup company from Scotts Valley in Santa Cruz County that provides the translucent panels.
The problem is that greenhouses are costly to build and consume electricity for lighting, climate control, and ventilation systems. But these solar panels offset energy costs while also taking advantage of the greenhouse structure to hold up panels, Alers said by telephone.
The panels also have a cooling effect, which will help in hot areas and also extend the growing period for certain crops.
“We are improving the economics of greenhouses,” Alers said.
The panels work a dual function by parsing sunlight.
A portion of the light spectrum is used to make electricity, while the red light portion of the spectrum that plants need to grow is magnified as it passes through the panels. This gives the panels a distinctive dark pink hue.
Alers was the part of a research group at UC Santa Cruz that in 2011 developed the technology in the Thin-Film Optoelectronics Laboratory of physics professor Sue Carter.
The researchers were experimenting with a fluorescent dye that absorbs light to make solar panels more efficient, according to UC press statement. But these experimental panels didn’t use the red light that plants need, and let it pass through.
UCR won’t be the first to use these panels. They have been installed at the University of California’s Davis and Santa Cruz campuses. Commercial growers in Watsonville, Nipomono and near Edmonton, Canada, also have installed the panels.
The ability to grow plants under solar panels may have larger implications for the environment.
In 2015, a study by UC Riverside biologists found that most of California’s large-scale solar projects have caused new environmental problems by consuming land important for wildlife habitat, agriculture and recreation.
Translucent panels could perhaps someday allow for farm fields to grow crops and produce electricity.
But that will take time.
“We are now focusing on greenhouses,” Alers said.
UC Riverside Is Building a Greenhouse That Will Produce Food and Solar Power, by David Danelski, The Press-Enterprise, March 11, 2017.