Sweden bets on magenta solar panels: they allow broccoli cultivation and electricity production on the same land

The coexistence of agriculture and photovoltaic power generation has emerged as a major challenge in the energy transition. While installing solar panels on agricultural land improves the utilization of available space, it creates a significant issue: the excessive shade cast by conventional modules can hinder crop growth.

To address this limitation, researchers at Mälardalen University in Sweden tested an innovative alternative using semi-transparent magenta solar panels capable of selectively filtering sunlight.

The experiment was conducted on broccoli crops and aimed to determine whether it is possible to share solar radiation between two simultaneous activities: food production and electricity generation.

How do magenta solar panels work

The technology hinges on a more efficient allocation of solar light wavelengths.

The magenta panels allow a substantial portion of red and blue radiation to pass through, targeting the specific spectral bands that plants utilize most effectively for photosynthesis. The remaining solar energy is intercepted by photovoltaic cells to generate electricity.

To assess the system, researchers deployed two experimental structures, each measuring approximately 20 meters by 20 meters. One structure incorporated panels with 50% transparency, while the other utilized modules with 70% transparency. As a baseline for comparison, a conventional plot fully exposed to sunlight was also cultivated.

The initiative has yielded promising results for broccoli cultivation.

Throughout the 2024 agricultural season, researchers monitored a range of variables, including temperature, soil and air humidity, photosynthetic activity, plant yield, and the nutritional quality of the harvest.

The findings were surprisingly favorable.

At harvest time, the broccoli grown beneath both types of panels yielded results very similar to those from the uncovered plot. This demonstrated that the partial reduction in light did not significantly impact the final production.

However, a notable difference was observed: the growth cycle was extended. Crops developed under the panels required approximately 25 additional days to reach commercial maturity.

Greater efficiency in light utilization

Although growth rates were lower, researchers observed a marked improvement in the plants' ability to utilize the available radiation.

In systems employing 50% transparent panels, light use efficiency was approximately 4.5 times higher than that recorded in crops exposed directly to sunlight.

For modules featuring 70% transparency, the improvement reached 2.8 times compared to conventional cropping methods.

According to the study's authors, these findings suggest that a more balanced distribution of radiation could optimize certain physiological processes in plants, even under conditions of reduced light intensity.

The challenge of balancing agriculture and energy production

The primary challenge facing this technology lies in striking the optimal balance between agricultural output and power generation.

The greater the amount of light that penetrates the panel and reaches the crops, the less energy remains available for conversion into electricity. Conversely, as the efficiency of power production increases, the radiation received by the plants diminishes.

The prototypes featured in the study incorporate cadmium telluride photovoltaic cells arranged in opaque strips across glass surfaces. The number of cells installed directly dictates the equilibrium between the dual uses of the land.

The electricity yield of these systems falls short of that generated by standard photovoltaic installations.

Researchers acknowledge that this approach results in lower energy output compared to conventional photovoltaic systems.

During the analyzed season, the magenta panels generated approximately 224.7 megawatt-hours per hectare, a figure roughly 100 megawatt-hours lower than that of a conventional ground-mounted solar installation of equivalent surface area.

This economic disparity will require careful evaluation in future commercial deployments.

Some experts argue that offsetting the reduced electricity generation would necessitate additional agricultural yields to balance the system's profitability, a calculation that depends on prevailing energy prices and the market value of the cultivated crops.

Potential applications in orchards and greenhouses

Researchers currently view the technology as particularly suitable for smaller-scale projects.

Among the most promising applications are community orchards, greenhouses and farms, where the generated electricity could be used directly to power irrigation, cooling, storage systems or agricultural machinery.

Any surplus energy could also be fed into the local power grid, thereby increasing the overall utility of the land.

The future of agrivoltaics, in color

The Swedish research team is continuing to explore new configurations using panels in various hues, including red and blue variants, to better isolate which aspects of the observed effects are specifically attributable to the magenta wavelength and which are merely a function of the total light transmission.

While long-term trials across diverse crops and climatic conditions remain necessary, the current findings indicate that it is possible to sustain agricultural yields comparable to those of conventional farming while simultaneously generating renewable energy on the same plot of land.

Amid rising global demand for food and clean electricity, such agrivoltaic systems could emerge as a valuable mechanism for maximizing land use, enhancing agricultural sustainability, and accelerating the energy transition without competing for available territory.