A US-Spanish research team investigated the ecological impact of a solar power system placed on a managed meadow using a hydraulic and soil hydrological model and field measurements. They found a minimal effect on plant carbon-water cycling, which they attributed to the plants’ photosynthetic properties changing to take advantage of the dynamic shading beneath the panels.
An international research group has studied the effect of ground-mounted solar power plants on meadows and found that they have a negligible effect on the carbon-water cycle of meadows.
The scientists also tried to answer questions about the water retention capacity and sustainability of the grassland ecosystem against weather conditions such as drought or heat waves, but the answer to this was not clear at the end of the study.
“We certainly did not find that the agrovoltaic array increased grassland resilience against drought,” said lead author Steven A. Kannenberg. pv magazine. “However, as noted in the paper, I would like to clarify the possibility that this is because the design of the model does not allow the grass to die back and then regrow after a drought, which is commonly observed in nature.”
To learn more about the effect of reduced light availability caused by solar photovoltaic systems on grassland photosynthesis, the researchers used a combination of field measurements and an established model of plant hydraulics and soil hydrology to simulate grassland physiology and hourly carbon-water fluxes. Over the course of 23 years.
They found that although the agroelectric system reduced light availability by 38%, photosynthesis and aboveground primary productivity were reduced by 6–7%. Another measure analyzed by the researchers, evapotranspiration, showed a 1.3 percent decrease compared to a comparison country that did not have a solar power plant.
The grassland area in the study is dominated by smooth brome (Bromus inermis), a common C3 pasture grass, the researchers said. It is located in Colorado on an east-west oriented 1.2 MW plant equipped with single-axis tracking systems and mounted on a flat panel height of 1.8 meters and a row spacing of 5.2 meters. The magazine states that efforts have been made to minimize the effects on the soil and vegetation. For example, the land was not graded for installation.
The researchers said the slight changes in the carbon-water cycle occurred largely because the photosynthetic capabilities of the plants under the solar panels changed to take advantage of the dynamic shading environment. They conclude that agricultural electrical systems can serve as a scalable way to expand solar energy production while maintaining ecosystem function in managed grasslands, especially in climates where water is more limiting to light.
“We plan to continue this research. This paper is one of the first of hopefully many to come out of the work done in Colorado. And we would always be interested in hearing about industry research on this topic,” said lead author Steven A. Kannenberg pv magazine.
The scientists presented their findings in the paper, “Solar system has little effect on carbon and water cycle in Grassland,” published in telecommunications environment. They come from Colorado State University and the Technical University of Madrid in Spain.