Researchers at the University of California, Santa Cruz, have created new solar panel technology they call Wavelength Selective Photovoltaic Systems. It uses part of the visible light spectrum to generate electricity while letting the rest of the light through to the plants growing inside. The results have been encouraging.
Wavelength Selective Photovoltaic Systems (WSPV) uses transparent roof panels embedded with a magenta luminescent dye to absorb some of the blue and green wavelengths of sunlight and transfer it to narrow photovoltaic strips that generate electricity. The other wavelengths pass through to the interior of the greenhouse. The result? Solar power that costs less per watt than conventional rooftop systems, and an increase in growth for many of the fruits and vegetables inside.
Inside two experimental greenhouses — one on campus and the other in Watsonville, California — the team raised 20 varieties of tomatoes, cucumbers, lemons, limes, peppers, strawberries, and basil. “80% of the plants weren’t affected, while 20% actually grew better under the magenta windows.
The experiment has demonstrated that ‘smart greenhouses’ can capture solar energy for electricity without reducing plant growth.
There’s more good news. The plants in the WSPV-equipped greenhouses used 5% less water than those raised in conventional facilities.
Using greenhouses to grow fruits and vegetables around the world has increased 600% over the past 20 years, and greenhouses now cover the equivalent of 9 million acres.
The Fraunhofer Institute For Solar Energy Systems in Germany is reporting that solar panels mounted high above farmland can increase the efficiency of each acre of land by as much as 60%. Global warming is already changing traditional farming. Greenhouses may be vital to feeding the planet in years to come as climate change makes some agricultural areas less productive, reducing yields per acre.