マゼンタ色の太陽光パネルは、アグリボルタイクスの最も巧妙なトリックかもしれない

Magenta solar panels may be agrivoltaics’ cleverest trick yet

DAILY SCIENCE

See-through solar cells harvest some wavelengths of light to make electricity, while passing through the red and blue wavelengths that plants need. In a new agrivoltaics experiment, broccoli yields held steady.

Let the best of Anthropocene come to you.

Vegetable farms and solar farms both need lots of sunlight and open space. But how do we divide our limited lands between these two priorities? One elegant solution is to put crops and solar panels on the same land—and share the broad spectrum of incoming sunlight between them.

A new study in Cell Reports Physical Science does this with photovoltaic cells that are semi-transparent: They capture some wavelengths of sunlight to make electricity, while letting the wavelengths most critical to photosynthesis pass through and reach the plants below. The new study suggests that broccoli can be grown in the magenta shade of these solar panels—without sacrificing the harvest.

Agrivoltaic schemes—putting plants and solar on the same land – could help us avoid clearing more land for human use. Climate studies suggest that this might work especially well across a wide sunbathed swath of the United States, from Texas up to Nebraska and west to California. Devoting just one percent of U.S. farmland to agrivoltaics could cover up to 20 percent of the nation’s electricity needs.

But traditional photovoltaic panels are opaque—and by shading plants, they can reduce crop yields. So engineers are trying to create new photovoltaic cells that divide the spectrum of sunlight between plants and electricity generation—similar to how governments segment different frequency bands for television, radio, cell phones, and other uses.

A 2020 study looked at panels that allow red wavelengths, critical for photosynthesis, to pass through—while harvesting green and blue wavelengths to make electricity. Basil grown under these panels produced similar yields, while spinach yields decreased. But the researchers estimated that by selling both electricity and crops, farmers growing spinach could generate 35 percent more income from the same land.

In the newest study, scientists evaluated a different kind of semi-transparent panel that lets most red and some blue wavelengths pass through—casting a magenta light on the plants—while converting much of the rest to electricity.

Broccoli cultivated under them grew more slowly, requiring an additional 25 days for harvest, but produced roughly the same yield. Meanwhile, these magenta sunscreens improved the microclimate below, reducing the “vapor pressure deficit”—a measure of when plants need to halt photosynthesis to avoid excessive water loss. This may have improved the plants’ efficiency in converting sunlight into plant biomass, which increased by 2.8- to 4.5-fold compared to unshaded plants.

The shaded plants’ levels of macronutrients such as calcium, magnesium, and phosphorus were either higher than or similar to unshaded plants, while levels of some micronutrients such as iron, copper, and zinc were slightly lower.

This was only a preliminary study. Future studies should look at larger plots, farmed across multiple seasons, and in different locations with varying climate and sunlight. It suggests that for now, the future of agrivoltaics might be best seen through rose-colored glasses.

Lu et al. “Evaluating land productivity with semi-transparent colored CdTe thin-film PV and broccoli cultivation in agrivoltaic systems.” Cell Reports Physical Science, 2026.

[画像: スウェーデンのKärrbo Prästgård農場にある実験サイトで、半透明の着色太陽光パネルの下で育つブロッコリー。 ©Silvia Ma Lu]