🥦 Pink solar panels grow broccoli

Broccoli grew beneath pink solar panels while the same plot of land continued to produce electricity.

This combination has a name: agrivoltaics. The principle involves installing photovoltaic panels above or near crops in order to use the same land for two types of production. But too much shade can slow plant growth and reduce yields.

Researchers tested another approach using semi-transparent photovoltaic panels with a magenta color. Made from cadmium telluride, they absorb certain wavelengths to produce electricity and let some light pass through to the plants below.

The experiment compared broccoli grown beneath these panels with other plants growing in direct sunlight. Despite the reduction and alteration in the light received, the vegetables harvested beneath the photovoltaic modules reached a size comparable to those in the control group.

Their growth nevertheless took more time. The broccoli protected by the panels reached maturity about 25 days later.

The plants, however, used the available light much more efficiently. The researchers calculated light-use efficiency to be about 4.5 times higher beneath the panels. Leaves adapt to their light environment and can alter their functioning when they receive less radiation.

The magenta color is not merely decorative. Plants do not use all wavelengths with the same efficiency for photosynthesis. A semi-transparent panel can therefore be designed to capture part of the solar spectrum while transmitting light that crops can still use.

The benefits must be tested across the entire plot. Even if electricity production and crop yields are not each individually maximized, combining them can make the land more productive overall. Shade can also reduce evaporation in some regions, but this benefit depends heavily on the climate and the crop.

The researchers now want to test other plants and different panel colors. Lettuce, tomatoes, and cereals do not respond to the amount and spectrum of light in the same way as broccoli.