2023 - 02 - 23
Impact of single-axis agrivoltaics systems on non-irrigated grassland
According to pv Magazine - FEBRUARY 20, 2023 BEATRIZ SANTOS US researchers are studying how agrivoltaic systems mounted on Single Pole Ground Mounting trackers affect rainfall and light redistribution at a 1.2 MW installation on grassland in Boulder, Colorado. Scientists at Colorado State University are investigating how the redistribution of rainfall and light caused by agrivoltaic systems mounted on single-axis trackers can affect the growth of non-irrigated grassland. The study is part of the Sustainably Colocating Agricultural and Photovoltaic Electricity System (SCAPES) project, funded by the US Department of Agriculture. “What we found is that on the drip edges of modules, depending on whether you’re tilting to the east or the west when there is a rainfall, you can get somewhere between two to five times the amount of precipitation dumped in one spot,” PhD student Matthew Sturchio told pv magazine. “If you want to quantify that for Colorado, it’s about changing the annual precipitation from 350 mm to 1,200 mm of rain. When you do that, you can really improve the amount of soil moisture that stays throughout the season, instead of letting it evaporate.” Sturchio and his team are conducting research on Jack’s Solar Garden, a 1.2 MW community solar garden in Boulder, Colorado. The project was installed in 2020 and features more than 3,200 380 W monocrystalline PV modules from Vietnam-based solar manufacturer Boviet Solar. The panels are mounted on single-axis trackers, one-third of them at 2.4 meters height, and the other two-thirds at 1.8 meters. Colorado has a semi-arid climate, with stronger rainfalls and temperatures around 35 C in the afternoons. Temperatures in the morning are around 22 C. The trackers tilt to the east in the morning, and to the west in the afternoon, following the sun. When it rains, this movement simulates the conditions of large rainfalls on either edge, with more water falling on the west edge due to the higher rainfall volumes in the afternoon. Consequently, the research team originally expected the west drip edge to show increased grassland productivity. Instead, they found that the east edge, with lower soil moisture, has higher grassland growth. They placed moisture sensors on the land and found that there is a 40 cm to 60 cm wide strip that benefits from the increased soil moisture from the drip edges. Experiments showed that air temperature and dryness also impact grassland productivity within and outside that strip. The temperature optimum for the grassland growing at Jack’s Solar Garden is a lot closer to 30 C than it is to the 35 C registered in the afternoons, according to Sturchio. “If you exceed 30 degrees, you are reducing the amount of photosynthesis that can happen for that plant,” he said. The team found that the lower air temperatures and reduced air dryness in the morning compensate for lower soil moisture, leading to increased productivity in the east edge. The shading provided ...
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