Solar farms and conventional agriculture are competing for land, and the conflict could get worse as the need for both increases. Scientists at UCLA have tested a way to combine the two by placing translucent solar cells on the glass roof of a greenhouse and found that they can actually improve plant growth inside. .
Greenhouses and solar energy both require large amounts of sunlight, so it’s no surprise that engineers experimented with building them into the same structure. Experimentation has shown that this is basically a win-win situation. Translucent solar panels can generate sufficient amounts of electricity without starving plants of essential sunlight. In some cases, plants even thrived under it.
For the new research, the UCLA team made some adjustments to an existing recipe. While they seem ideal for greenhouse use, the downside is that these organic materials degrade rapidly in sunlight.
So the team added a new ingredient, a layer of a chemical called L-glutathione, to prevent organic substances from oxidizing and breaking down. Organic solar cells were placed under solar irradiation for 1,000 hours of continuous use. And sure enough, the one with the extra layer maintained over 84% of its original efficiency, while the one without the extra layer dropped to less than 20% in the meantime.
The researchers then ran the solar cells in a model greenhouse to grow wheat, mung beans, and broccoli. Each crop he grew in one of he two greenhouses. One is a transparent glass roof interspersed with segments of inorganic solar cells, and the other is composed entirely of translucent organic solar cells.
The organic cell showed a power conversion efficiency of 13.5% and passed 21.5% of visible light. But it seems that was enough. The plants in these greenhouses, surprisingly, thrived even better than those in conventional greenhouses. The team suggests this is because the L-glutathione layer blocked ultraviolet light, which can damage plants, and infrared light, which can overheat greenhouses.
“We didn’t expect organic solar cells to outperform traditional glass-roofed greenhouses,” said Yepin Zhao, lead author of the study. “But we repeated the experiment over and over again with the same result. Further research and analysis showed that the plants didn’t need as much sunlight as we originally thought to grow. In fact, too much sun can be harmful, especially in a sunny climate like California.”
The team has now established a start-up to commercially scale production of these organic solar cells.
A study was published in a journal natural sustainability.
Source: UCLA
