When researchers at Mälardalen University in Västerås, Sweden, installed magenta solar panels and tried to grow broccoli underneath, the plant unexpectedly absorbed more light energy than plants grown in open sunlight, resulting in lower overall energy use and a similar crop yield.
Although the panels used in the experiments are not commercially available, the research team said similarly designed magenta solar panels that allow the light wavelengths plants require, rather than commercially available opaque panels, could allow farmers to use different wavelengths to generate electricity and sustain or improve crop yields.
Magenta Solar Panels Could Generate Electricity and Illuminate Crops
Conventional solar panels offer farmers the dual benefit of generating electricity and protecting delicate crops from harsh weather like heavy rainfall or hail, as well as excessive sunlight. However, currently available models are opaque, which can reduce available sunlight to a point that adversely affects yields.
When exploring more translucent alternatives, team leader Silvia Ma Lu of Mälardalen noted that more research is still needed to understand how different crops respond to different solar panel system configurations and climatic conditions. The lead author also noted that the challenge is designing systems that balance agricultural needs with power generation.
“There is no single agrivoltaic design that will work optimally everywhere,” Ma Lu said.
Because broccoli is a highly nutritious crop available worldwide, the researchers considered alternative configurations, including translucent magenta solar panels. They also noted that the cruciferous vegetable is well suited to the local Swedish climate.
Tests Show Similar Crop Yields and Improved Efficiency Over Direct Sunlight
To start, Lu and colleagues built a pair of self-contained, 20-meter-by-20-meter systems using semi-transparent, magenta-colored solar panels. Critically, the magenta solar panels had different levels of transparency, allowing the planted broccoli to receive different amounts of sunlight.
To increase yields, the magenta panels boosted the blue and red wavelengths that reach the broccoli. As a control plot, the research team also planted a third patch of broccoli that was exposed to open sunlight.
“The basic concept is quite straightforward,” Ma Lu explained. “The solar panels use part of the incoming sunlight to generate renewable electricity while allowing part of the light to pass through to the crops growing underneath.”
Over the standard 2024 growing season, the team compared the progress of broccoli grown under both types of magenta solar panels and the third open-sunlight control plot. This included monitoring each system’s air temperature, relative humidity, and soil moisture. The research team said they also tracked crop yield, nutrient composition, and “how well the plants performed photosynthesis.”
After comparing results, Ma Lu and colleagues found that broccoli crops grown beneath magenta solar panels “showed a 4.5-fold increase in how efficiently they used sunlight,” regardless of opaqueness.
“One of the most interesting findings was how similarly the broccoli performed under the two solar panel systems despite their different transparency levels,” Ma Lu said.
The plants also grew as large as the traditionally grown outdoor group. However, the researchers noted that the solar panel-covered plants required an additional 25 days to reach maturity.
Farmers Could Protect Crops and Generate Electricity to Use or Sell
When discussing potential limitations, the team explained that its systems were prototypes. Ma Lu added that more research is needed “at larger scales and over multiple growing seasons,” to truly confirm their initial results.
“These findings are specific to our experimental conditions and should be validated across additional growing seasons and system configurations,” she explained.
If successful, the team suggested that systems based on their magenta solar panels design could potentially scale up for commercial use, offering farmers the opportunity to protect crops and generate sellable electricity.
“Electricity generated from crops could, in principle, power farm operations such as irrigation, machinery, or cooling and storage systems, or it could be supplied to the electricity grid,” they explained.
Allocating Different Portions of the Solar Spectrum
Ma Lu and colleagues said they have already begun evaluating magenta solar panels to see which ones maximize growth and energy generation. The team is also testing red and blue panel designs in controlled lab settings to ensure the broccoli doesn’t receive any light that didn’t pass through the panels.
When discussing potential applications, Ma Lu said designs similar to those tested in the lab may already suit smaller-scale applications, including community gardens. The team leader also said growing systems with magenta solar panels could be placed on greenhouse roofs “rather than immediate deployment over large agricultural areas.”
Beyond commercial applications, Ma Lu said the broader goal of the research is to “investigate whether sunlight can be used more efficiently by allocating different portions of the solar spectrum to crop growth and electricity generation.”
Christopher Plain has spent the last six years as Associate News Editor and Head Science Reporter at The Debrief. Follow and connect with him on X, learn about his novels at plainfiction.com, or email him at christopher@thedebrief.org.