Source: Earth’s Future
Introduced in the 1980s, agrivoltaics, or AV, is the concept of pairing agriculture and solar energy production on the same plot of land. Practitioners grow crops under solar panels and can control the amounts and wavelengths of light that pass through for photosynthesis. Light that is not necessary for photosynthesis can power clean energy production. Meanwhile, as plants photosynthesize, they lose water through transpiration. That water loss cools the air and improves the efficiency of energy generation by the panels. It’s a win-win scenario—at least in theory.
Significant challenges for AV, however, have hampered widespread adoption. One pressing question is how AV can maximize crop productivity and energy generation while minimizing plant water loss and irrigation demand. It is a lot to ask of one plot of ground.
In a previous study, scientists argued that successful AV setups could partition light into wavelengths that are efficient for either energy production or photosynthesis: red for crops and blue for solar panels, for example. Building on that work, Katul developed a mathematical framework to quantify how individual plants use various wavelengths of light in photosynthesis. The study asked how photovoltaic systems colocated with agriculture would affect aboveground biomass, which researchers use to estimate crop yield.
The model considers an individual plant and introduces variables, such as the degree to which a plant is shade tolerant, that could affect its growth beneath a photovoltaic setup. The framework assumes that resources such as light are harvested on the basis of the leaf area but the respiratory costs are proportional to the size of the plant. The study also considers how solar panels alter the microclimate and light availability beneath their cells.
The commentary highlights that candidate crops for AV are shade tolerant and have large leaf areas aboveground. Reduced air temperature and higher soil moisture below the photovoltaic system allow plants to allocate more carbon to aboveground biomass, resulting in greater leaf area. This trait is common in shade-tolerant plants and suggests that big leafy crops such as arugula, kale, and tomatoes may be more likely to succeed in an AV setup.
The next step, the author says, is to consider factors like the crowding density of crops to scale the findings up beyond a single plant. (Earth’s Future, https://doi.org/10.1029/2023EF003512, 2023)
—Aaron Sidder, Science Writer