Researchers at North Carolina State University installed translucent solar cells on the glass roof panels of greenhouses to capture sunlight that plants would not use, and found that in certain climatic conditions, batteries could produce enough solar energy to make the greenhouse completely self-sufficient.
This organic solar cell (OSC) offers some advantages over other designs. They still collect energy from the sun, but can be more flexible, transparent (or at least translucent) and can be adjusted to absorb only certain wavelengths of sunlight, which makes them ideal for greenhouse roofs, where they can harvest enough energy to meet the greenhouse’s energy needs through the light needed by most plants.
For this study, the theoretical greenhouse was modeled on the energy needed to grow tomatoes in three different climate regions (Arizona, North Carolina, and Wisconsin). In addition, OSC is an effective insulator that helps maintain the appropriate temperature. The team found that the amount of light available to the internal plants would be minimally affected, but the benefits were worth it. In sunny Arizona, for example, an OSC-installed greenhouse can be turned into an energy-independent greenhouse that blocks only 10% of the light needed for plants. The team says there is no negative impact on plants. In fact, with a little bit of light, the energy output can be doubled.
In North Carolina, daylight is sparse, so greenhouses will need to block 20% of photosynthesis to become energy neutral. In Wisconsin, the greenhouse is still designed to meet half of its energy needs.