Agrovoltaics – the practice of placing solar installations next to farmland – is being adopted more frequently around the world as a way to introduce distributed clean energy without compromising land use.
According to research from Oregon State University, the co-location of solar and agricultural energy could provide 20 percent of the total electricity generation in the United States. According to the researchers, the large-scale installation of agrivoltaics could lead to an annual reduction of 330 thousand tons of carbon dioxide emissions with a “minimal” impact on crop yields.
According to the study, an area the size of the state of Maryland would be needed for agrovoltaics to cover 20 percent of the electricity generation in the United States. That’s about 13,000 square miles, or 1 percent of the current U.S. agricultural acreage. On a global scale, it is estimated that 1 percent of all farmland could produce the energy the world needs if converted to solar photovoltaics.
There are many ways to install agrovoltaic panels. One of the most common methods is to elevate the facility to make room for farm equipment or livestock to move freely underneath. Another fashionable design is to orient the photovoltaic panels vertically, leaving wide open spaces between the rows of panels.
United States
In Somerset, California, German-designed Sunzaun vertical solar panels were installed on a vineyard. The installer Sunstall developed the installation, consisting of 43 450 W modules connected to a microinverter and two batteries.
The minimalist design used holes in the frames of the modules to make a simple attachment to two piles, which avoided the need for a heavy shelving system. Bifacial solar modules produce energy on both sides of the vertically oriented array.
In traditional systems designed with horizontal orientation, the rails used to mount the panels on the shelving system are usually cut to fit the intended size of the panel. If the panel size changes after the procurement of all other components has been completed, the project may experience delays while the rails are redesigned to accommodate the updated panel size. The Sunzaun design allows to easily adapt to a change in the size of the panel by adjusting the distance between each stack. It is also possible to adjust the height of the panels from the ground if necessary.
Germany
Scientists from the Leipzig University of Applied Sciences have studied the potential impact of the massive deployment of west-east oriented vertical photovoltaic systems on the German energy market. They have found that these installations could have a beneficial effect on stabilizing the country’s grid, while allowing for greater integration with agricultural activities than conventional ground-mounted photovoltaic plants.
The scientists found that vertical photovoltaic systems can shift solar performance towards the hours of highest electricity demand and most electricity supply in the winter months, thereby reducing solar restriction.
”If an electricity storage of 1 TW of charging and discharging power and 1 TWh of capacity is integrated into the energy system model, the effect is reduced to a CO2 saving of up to 2.1 Mt/a with 70 percent of vertical modules oriented from east to west and 30 percent inclined to the south,” they said. “Finally, although it may seem unrealistic for some to achieve a rate of 70 percent of vertical power plants, even a lower rate has a beneficial impact.”
Japan
In Japan, Luxor Solar KK, a subsidiary of the German module manufacturer Luxor Solar, built an 8.3 kW vertical photovoltaic system in the parking lot of a rice processing factory owned by Eco Rice Niigata.
“The cars will be parked between the vertical systems”” Uwe Liebscher, managing director of Luxor Solar KK, explained to PV magazine. “The goal of this system is to show the durability during the winter and the additional energy performance due to the reflection of the snow.” Niigata, on the other hand, is known for being a high snow load area, with up to 2 or 3 meters of snow in winter.”
The south-facing system features Luxor Solar’s own heterojunction solar modules, as well as mounting systems from German vertical photovoltaic specialist Next2Sun and inverters from Japan’s Omron. The vertical assembly will supply electricity to a rice processing factory located next to the system. The city of Nagaoka financed the project with 2 million yen ($14,390).
“A vertical installation uses only a minimum space of the farmland, while maintaining more than 85 percent of the light that reaches the crops, which ensures an optimal balance between solar energy and agriculture, something crucial in Japan,” he explains. “This allows us to build agrivoltaic systems on public utility farmland, such as for wheat, potatoes or rice, on a large scale.”
France
In France, TotalEnergies and InVivo, a specialist in agrovoltaics, have launched a 111 kW vertical agrivoltaics demonstrator. TotalEnergies said the pilot installation will investigate the impact of solar panels on agricultural yield, as well as biodiversity, carbon storage and water quality of the site.
“We are convinced that the synergies developed between green electricity production, biogas and agriculture are one of the answers to guarantee our energy and food independence,” said Thierry Muller, CEO of TotalEnergies Renouvelables France.
Sweden
Scientists from the University of Mälardalen (Sweden) have developed a computational fluid dynamics (CFD) model that facilitates the analysis of microclimates in vertical photovoltaic projects. CFD simulations are used to solve complex equations about the flow of solids and gases through and around bodies, which can be employed to analyze microclimates within agrivoltaic systems.
“Agrivoltaic (AV) system models will be frequently used for the design of new AV systems, as well as for decision-making, since microclimatic changes can be analyzed/predicted based on the location and solution of the AV system,” researcher Sebastian Zainalli told pv magazine.w
The study observed a 38 percent decrease in the intensity of solar radiation in the ground areas shaded by the vertical photovoltaic modules.
Key principles
The US National Renewable Energy Laboratory offered five principles for the success of agrovoltaics, including:
Climate, soil and environmental conditions: The environmental conditions of a place must be suitable for both solar generation and the desired crops or vegetation cover.
Configurations, solar technologies and designs: The choice of solar technology, the layout of the site and other infrastructures can affect everything from the amount of light that reaches the solar panels to whether a tractor, if necessary, can pass under the panels. “This infrastructure will be on the ground for the next 25 years, so it has to be done right for the intended use. The success of the project will depend on it,” says James McCall, an NREL researcher working on InSPIRE.
Crop selection and growing methods, seed and vegetation designs, and management approaches: Agrivoltaic projects should select crops or groundcovers that thrive under the panels in their local climate and that are profitable in local markets.
Compatibility and flexibility: Agrovoltaics must be designed in a way that adapts to the conflicting needs of solar installation owners, solar operators and farmers or landowners to enable efficient agricultural activities.
Collaboration and Partnerships: For any project to be successful, communication and understanding between groups is crucial.
A source: https://www.pv-magazine-mexico.com
