Growing Crops at Solar Farms Can Enhance Panel Performance and Longevity – Study

March 10, 2023

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by Simon Yuen (PV Tech) Growing commercial crops on solar farms could increase solar panel performance and longevity, according to a recent study conducted by Cornell University.

The engineers at the university proved that solar panels mounted over vegetation had lower surface temperatures compared to those arrays built over bare ground. Also, by mounting solar panels four metres above a soybean crop, solar modules would show temperature reductions by up to 10 degrees Celsius compared with solar panels mounted a half-meter above bare soil.

“There is potential for agrivoltaic systems, where agriculture and solar panels coexist, to provide increased passive cooling through taller panel heights, more reflective ground cover and higher evapotranspiration rates compared to traditional solar farms,” said Max Zhang, co-author of the study and professor at the Sibley School of Mechanical and Aerospace Engineering.

Even relatively built-up regions can accommodate commercial crops and solar farms. In 2021, about 40% of utility-scale solar farm capacity in New York state was developed on agricultural lands. About 84% of land deemed suitable for utility-scale solar development was agricultural as well.

Moreover, the combination of commercial crops and solar farms was suitable in hot climates such as the western US, according to another Cornell University study. READ MORE

Made in the shade: Growing crops at solar farms yields efficiency (Cornell Chronicle)

The potential for agrivoltaics to enhance solar farm cooling (Applied Energy)

Agrivoltaics may be one answer to solar buildout in Tennessee -- Researchers at the University of Tennessee found that operational and contracted utility-scale solar installations in the state will require up to nearly 15,000 acres of land. To meet Tennessee Valley Authority’s goal of adding 10 GW by 2035, another 100,000 acres of land will be needed. (PV Magazine)

Can Farming and Solar Panels Coexist? Just Wait Until You See What They're Doing in Canada (AgWeb)

Excerpt from Cornell Chronicle: The group published new research Feb. 15 in Applied Energy.

“We now have, for the first time, a physics-based tool to estimate the costs and benefits of co-locating solar panels and commercial agriculture from the perspective of increased power conversion efficiency and solar-panel longevity,” said lead author Henry Williams, a doctoral student in Cornell Engineering.

“There is potential for agrivoltaic systems – where agriculture and solar panels coexist – to provide increased passive cooling through taller panel heights, more reflective ground cover and higher evapotranspiration rates compared to traditional solar farms,” said senior author Max Zhang, professor in the Sibley School of Mechanical and Aerospace Engineering, “We can generate renewable electricity and conserve farmland through agrivoltaic systems.”

In New York, for example, about 40% of utility-scale solar farm capacity has been developed on agricultural lands, while about 84% of land deemed suitable for utility-scale solar development is agricultural, according to a previous research study from Zhang’s group.

By using a computational fluid dynamics-based microclimate model and solar panel temperature data, the group evaluated solar panel height, the light reflectivity of the ground and rates of evapotranspiration (the process where water vapor rises from the plants and soil). They found that agrivoltaic systems can potentially help resolve future global food-energy problems.

The engineers showed that solar panels mounted over vegetation reveal surface temperature drops compared to those arrays built over bare ground. Solar panels were mounted 4 meters above a soybean crop and the solar modules showed temperature reductions by up to 10 degrees Celsius, compared with solar panels mounted a half-meter above bare soil.

The cooling effect due to enhanced evapotranspiration and surface albedo from vegetation and soil is more significant than that induced by greater panel height; and the passive cooling adds to solar panel efficiency, compared with exposed soil or gravel, according to the paper. Better yet, however, the temperature drops leads to an improved solar panel lifespan – and improved, long-term economic potential.

“As you decrease the solar panel operating temperature, you can increase efficiency and improve the longevity of your solar modules,” said Williams, “We’re showing dual benefits. On one hand, you have food production for farmers, and on the other hand, we’ve shown improved longevity and improved conversion efficiency for solar developers.”

Understanding this mutually beneficial concept comes at a critical time for agricultural production, as global food demands are expected to increase by 50% by 2050, to feed an anticipated 10 billion people, according to the World Resources Institute. At the same time, it is imperative to accelerate the deployment of renewable energy to mitigate the impact of climate change.

In hot climates like the western United States, agrivoltaic farms would be ideal.

“Up to this point, most of the benefits from agrivoltaic systems have revolved around hot and arid climate zones,” said Zhang, also the Kathy Dwyer Marble and Curt Marble Faculty Director for the Cornell Atkinson Center for a Sustainable Future, “This paper is taking a step toward evaluating the viability of agrivoltaics in climates representative of the Northeastern U.S. in relaxing the land-use competition the world faces.”

In addition to Zhang and Williams, on the paper, “The Potential for Agrivoltaics to Enhance Solar Farm Cooling,” the other authors are Khaled Hashad Ph.D. ’21 (Engineering), and Haomiao Wang, a master’s degree student in engineering. READ MORE

Excerpt from AgWeb: One common solution to farmland installations is grazing underneath the panels. The combination works for pastured sheep and cattle, especially although I would never underestimate the ability of cows to rub any post loose. As extreme heat becomes more common, shade becomes more valuable for pastured livestock.

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Another mixture of solar and ag that caught my attention was this intercropping experiment. The first thing I noticed were the solar panels were fixed vertically, which would drastically lower electrical output – at my latitude, anyway.

This photo though is from Alberta, Canada, where the sun hits at a much lower angle, decreasing the efficiency loss enough to make something like this idea less unthinkable.

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Still, as an older farmer whose ability to operate a million-dollar combine safely in huge open fields is a subject of continuing discussion on our farm, the idea of driving accurately between expensive solar arrays, even with amazing electronic assistance, is something better left to Canadians, perhaps. READ MORE