Imagine a greenhouse that can be used to grow plants while generating electricity. Sound like a great idea? Now picture a magenta greenhouse — walls and ceiling all in a deep shade of purplish-red with embedded photovoltaic cells. This could be the greenhouse of the future.
Researchers at the University of California have designed a greenhouse that can generate more than enough electricity needed to run the greenhouse fans and monitors by using “electricity- generating windows (Wavelength- Selective Photovoltaic Systems)” for the glazing. The walls and roof are made of plastic embedded with a luminescent red dye. Narrow strips of photovoltaic material throughout the glazing generate electricity.
The glazing generates less energy than a traditional photovoltaic cell but it does so at low cost and with the huge advantage of functioning as a greenhouse glazing.
The scientists state: “At 7 per cent power efficiency, the power price is about $0.65/W, an approximately 40 percent decrease compared to the Si-PV cell” (the silicon photovoltaic cell commonly used in commercial solar panels).
The red colour of the glazing affects light transmission yet does not seem to have a negative effect on plant growth. Researchers compared the growth of 18 types of crops, including tomatoes, cucumbers and strawberries, in the photovoltaic greenhouses to the growth of crops in a conventional greenhouse. No plants suffered from the red light, and some crops grew slightly better and/or used less water when grown in the magenta greenhouse.
Source: Wavelength-Selective Solar Photovoltaic Systems: Powering Greenhouses for Plant Growth at the Food-Energy- Water Nexus. Michael E. Loik, Sue A. Carter, Glenn Alers et al. Earth’s Future, 2017. Volume 5. pp1-10.
- Janet Wallace