Solar-Powered Farms: Agri-PV Beginners Guide - Five Essential Things to Know for Growing with Solar Power

Getting the most out of your land doesn’t have to be solely a function of the crops you plant anymore. As solar technologies continue to evolve, a new option has become available to farmers that supports the growth of crops while also harvesting and selling the sun’s energy at the same time. Known as agrivoltaics (or Agri-PV), a solar energy installation on your farm can possibly provide you an additional revenue stream, and many farms worldwide take advantage of this dual land-use approach.

A report from OSTI, the US Department of Energy Office of Scientific and Technical Information, shows that countries like Japan, China, France, the US, and South Korea are providing national funding programs, and the overall electrical generation capacity of Agri-PV projects worldwide has grown by over 500% since 2012 Japan, for example, has almost 2,000 Agri-PV installations covering more than 120 kinds of crops.

If you’re considering exploring agrivoltaics, you’ve undoubtedly got some questions. Here are a few of the most common questions farmers ask about solar energy and how it works on the farm.

1. What’s the difference between Agri-PV and solar-powered farms?

Agri-PV describes the combined use of the same land for growing crops and producing solar energy. The panels can either be aligned between rows of crops or mounted as a completely overhead system with crops growing underneath. To compare, traditional solar-powered farms may have solar panels on the roof of the barn, cow shed, or other buildings to generate electricity for farming facilities or even the home or offices while maintaining land use primarily for crops.   A ground-mounted solar installation, in contrast, exclusively uses land for solar energy generation, which loses the potential to grow crops underneath the solar panels. Dual-use of the land in Agri-PV is a more efficient approach as it allows for both crops and solar energy to be produced together. Other related dual-use applications utilize solar panels to create a corral for livestock or use solar panels floating on pontoons over fishponds or reservoirs.

2. What are the benefits of Agrivoltaics?

Essentially the benefits of an Agri-PV system can be understood in terms of what it does for your crops, what it produces in terms of energy, and the levels of integration it can offer between the two worlds. From the perspective of crops, using the shade created by the Agri-PV system can result in higher crop yields, lower water usage, and lower fertilizer usage. The microclimate under solar panels generally has a lower level of moisture evaporation and a cooler temperature relative to the surrounding area due to the shade provided by the panels. The panels can also shield your crops from severe weather. Solar trackers, which adjust the angle of the panels according to sunlight and crop type, find an optimal balance between energy generation and crop shading - potentially resulting in higher yields of crops and energy.

Some of the energy produced can be used to power the farm’s electric machinery and vehicles, resulting in reduced electricity costs and cleaner production. Excess energy produced can be sold, either via a fixed contractual arrangement with a utility company or by enabling a subscriber base to receive their power from your farm.

3. What crops are best suited for Agrivoltaics?

An Agri-PV system creates a microclimate under the panels with its own characteristics – generally increasing shade and moisture retention relative to the surrounding environment. According to research from Fraunhofer, certain crops like grapes, berries, and apples tended to grow better due to more consistent shade profiles and reduced water stress as a result of the panels overhead. Shade-tolerant crops that only require a few hours of sunlight per day, like beets, lettuce, or spinach are also a good choice for growing in the shaded environment underneath solar panels. With Agri-PV, the evaporation of water under the panels is slowed significantly, in some cases by 40 or 50%. So while traditional crops like celery and potatoes showed a decline in crop yields during normal weather conditions with solar panel shading, during a year with unusually hot and dry weather conditions, they both exceeded their projected growth baseline by over 10% under Agri-PV.

Solar panels, therefore, seem to do well with shade-tolerant crops in consistently hot and dry environments due to the microclimate that Agri-PV can create. For example, a recent University of Arizona study showed an increased yield of chiltepins, jalapenos, and cherry tomatoes generating 2 to 3 times more quantity than in a traditional agricultural setting. Having said that, with climate change and the global temperature on the rise, climate becomes a very important factor due to increasing demands on the water supply, and even crops that are not shade-tolerant have been proven to grow better under certain levels of shade.