May 11, 2021

A team of researchers at North Carolina State University has shown that using semi-transparent organic solar cells (OSCs) can help greenhouse growers generate electricity and reduce energy use while still cultivating viable crops of lettuce.

The research found that red lettuce can be grown in greenhouses with OSCs that filter out the wavelengths of light used to generate solar power. The researchers grew crops of red leaf lettuce in greenhouse chambers from seed to full maturity under constant conditions, apart from the lighting regime.

A control group of lettuces was exposed to the full spectrum of white light, while the rest were dived into three experimental groups. Each of those groups was exposed to light through different types of filters that absorbed wavelengths of light equivalent to what different types of semi-transparent solar cells would absorb.

To determine the effect of removing various wavelengths of light, the researchers assessed a host of plant characteristics, such as leaf number, leaf size, and lettuces weight, as well as how much CO2 the plants absorbed and the levels of various antioxidants. “Not only did we find no meaningful difference between the control group and the experimental groups, but we also didn’t find any significant difference between the different filters,” said study co-author Brendan O’Connor.

“We were a little surprised – there was no real reduction in plant growth or health,” added Heike Sederoff, co-author of the study and professor of plant biology. “It means the idea of integrating transparent solar cells into greenhouses can be done.”

Lead photo caption: The study suggests transparent solar panels will not affect lettuce crop growth