More and more fruit and vegetables are now grown in greenhouses. However, the challenge posed by this cultivation method remains the supply of energy to the structure in order to achieve greater autonomy.
A team of researchers at North Carolina State University has addressed the issue in an experiment aiming to equip the glass of greenhouses with semi-transparent organic solar cells (or ST-OSC). In order to conduct the experiment, red leaf lettuce was exposed to different types of glass and different wavelengths of light, without changing the other variables, including the temperature, CO2 concentration, as well as the water and input levels.
The outcome was that the solar cells supplied the energy necessary for the greenhouse, by regulating its temperature without impacting the growth of the plants. “We were a bit surprised. The growth and health of the plants did not really seem to be affected. This means that the idea of integrating transparent solar cells in greenhouses can be realized,” explains Heike Sederoff, biologist at North Carolina State University.
The innovation of these cells resides in their flexibility. Contrary to conventional photovoltaic cells, they can indeed absorb different wavelengths depending on the chosen setting.
This is a real development in the construction of energy-neutral greenhouses, as greenhouse farming can sometimes require more energy than other types of farming.
“Based on the number of people who have contacted me about solar-powered greenhouses when we published previous work, there is a lot of interest from many producers. I think that this interest will only continue to grow. We have had enough prototypes and proofs of concept to know that this technology is viable in principle. We just need to see a company take the leap and start producing on a large scale.”