A new study published in the Cell Reports Physical Science journal has proved that it's possible to use semi-transparent solar panels, which are specifically designed to only absorb the light wavelengths that plants don't need, on greenhouse roofs to generate electricity without affecting the plants' growth.
"We were surprised: there was no real reduction in the plants' growth or health," stated Heike Sederoff, a corresponding co-author of the study and a professor of plant biology at North Carolina State University.
Previous NC State studies focused on how much energy solar-powered greenhouses could produce depending on their design and location. However, up until now, it was unclear how these semi-transparent solar panels could affect greenhouse crops.
To address the problem, the researchers grew red leaf lettuce (Lactuca sativa) in greenhouses for 30 days, from seed to maturity, monitoring their growing conditions, from temperature and water to fertilizer and CO₂ concentration.
A control group of lettuces was exposed to the full spectrum of white light, while the rest of the lettuces were divided into three experimental groups. Each of these groups was exposed to light through different types of filters that absorbed wavelengths of light equivalent to those that different types of semi-transparent solar cells would absorb.
"Not only did we find no significant difference between the control group and the experimental groups, but we also found no significant difference between the different filters," stated Brendan O'Connor, study co-author and associate professor of mechanical and aerospace engineering at NC State.
"This is promising for the future of solar greenhouses," emphasizes Harald Ade, study co-author and Goodnight Innovation Distinguished Professor of Physics at NC State. "It would be difficult to get producers to use this technology if there was a loss of productivity. But now it is a simple economic argument as to whether the energy produced and saved could offset the investment made in new greenhouse technologies," he stated.