Generally, greenhouses and plants both need a lot of sunlight in order to flourish. A team of researchers from North Carolina State University has looked into creating a system that utilizes energy coming from see-through solar panels.
The way the energy is harnessed is through the wavelengths of light that plants don't use for photosynthesis.
The team's findings were published in the journal Joule.
Turning greenhouses into energy neutral spaces
"Plants only use some wavelengths of light for photosynthesis, and the idea is to create greenhouses that make energy from that unused light while allowing most of the photosynthetic band of light to pass through," said Brendan O’Connor, corresponding author of the study and an associate professor of mechanical and aerospace engineering at NC State.
O'Connor continued "We’re able to do this by using organic solar cells because they allow us to tune the spectrum of light that the solar cell absorbs – so we can focus on using mostly wavelengths of light that plants don’t use. However, until now it wasn’t clear how much energy a greenhouse could capture if it was using these semitransparent, wavelength selective, organic solar cells."
Greening greenhouses with organic PV: Semi-transparent organic solar cells can reduce the carbon footprint and raise the crop yield of greenhouses while acting as generators and insulation. Scientists in the U.S. say… https://t.co/c0Wzvxicbp#solarenergy#solarpv#solarpic.twitter.com/jaqlGc3Zlu— pv magazine (@pvmagazine) February 11, 2020
Organic solar cells (OSCs) gather energy from sunlight, however, they can be more flexible, even partly transparent, and tuned to absorb specific wavelengths of light.
Using OSCs as roofing for greenhouses could potentially work out perfectly. Enough light is let through for the plants within them to grow happily, all the while the panels are harvesting enough to offset a good amount of the greenhouse's energy requirements.
These could be critical support systems in the near future.— Larry Rowe (@oldtimer1968) February 11, 2020
If we can get around some of the economic bottlenecks we may be able to create a new technical human/animal/plant life support system:https://t.co/TppI9ZFPs5
By modeling their premise over three different U.S. locations: Arizona, North Carolina, and Wisconsin, the team was able to discover where these types of solar celled semi-transparent greenhouses would best function to be energy neutral.
In Arizona, where sunshine abounds, a greenhouse with OSCs could be energy neutral while only blocking 10% of the plants' sun. In slightly less sunny North Carolina, the greenhouse could do so by blocking 20% of natural daylight, and finally, in much less sunny Wisconsin where the winters last longer, neutrality would not be reached, however, these greenhouses could still generate nearly half of their energy needs in this way.
O'Connor stated "While the technology does use some of the light plants rely on, we think the impact will be negligible on plant growth – and that the trade-off will make financial sense to growers."