Pairing Solar Power and Agriculture in the Pacific Northwest

By Morgan Lawrence, USDA Northwest Climate Hub

Row of a cucurbit crop alongside row of solar panels
Crops can be grown beneath solar panels to reduce their exposure to the sun and protect from extreme heat. Photo: Oregon State University NEWAg Lab

Climate change has caused unprecedented warming, varying precipitation patterns, and higher risks of drought and wildfires across the Northwest. These impacts threaten agriculture, natural resources, and human health in the region. Transitioning from fossil fuels to renewable forms of energy can reduce carbon emissions and slow the effects of climate change. However, renewable energy often requires large tracts of land—a requirement  that can conflict with agricultural land requirements. Agrivoltaics could present a solution.

Also known as dual-use solar and agrisolar, agrivoltaics pairs solar power generation with agriculture, generating low-carbon energy while providing space for crops, grazing, and pollinator habitat. In this mutually beneficial arrangement, solar panels offer plants and animals shade and protection from extreme heat and drought, and plant evapotranspiration cools solar panels and improves their energy generation. By co-locating agriculture and solar and providing potential benefits to producers, agrivoltaics can also quell concerns that solar energy land requirements could limit agricultural production. A recent Oregon State University study found that converting less than 1% of U.S. agricultural land to agrivoltaics could meet 20% of the country’s energy need. Though these systems require thoughtful design, agrivoltaics could help the Northwest transition to renewable energy while minimizing impacts to agriculture and agricultural land.

There are three main types of agrivoltaic systems: elevated, inter-row, and a combination of the two. Elevated systems place solar panels directly above vegetation. Crops such as berries, grapes, and apples can be found in these systems. In inter-row systems, vegetation is grown between rows of solar panels. Rows of panels can be spaced out widely enough to allow tractors and other equipment to cultivate vegetation. Crops such as grasses, grains, and hardy vegetables (such as kale and broccoli) can be found in inter-row systems. Beekeeping and livestock grazing can occur in both elevated and inter-row systems, as can habitat restoration.

In addition to mitigating carbon emissions and reducing solar siting conflicts, agrivoltaic systems have several other potential benefits. For example, the electricity generated by solar panels can be used to power farm operations, which can reduce energy costs for producers. In some cases, solar panels may even generate enough energy to sell the excess, increasing and stabilizing farm income. Solar panels can also help to improve crop resilience by offering protection from the impacts of extreme heat and drought. For example, researchers in Oregon are exploring how agrivoltaics can reduce drought stress and blossom end rot in dry-farmed tomatoes. In some cases, agrivoltaics can even boost plant production. A 2021 project in Oregon found that potatoes grown in the shade of solar panels had an overall yield increase of 20% compared to potatoes grown in full sun (Garrett et al. 2021).

Row of tall plants, likely tomato or pepper, growing under a row of solar panels
An example of an elevated agrivoltaic system, where solar panels are at least six feet above vegetation. Photo: National Renewable Energy Laboratory.

Agrivoltaic systems can also create opportunities for sheep, chickens, and other animals to graze. In return, panels offer shade for animals. For example, researchers at Oregon State University found that sheep raised in agrivoltaic settings prefer to graze in the shade of solar panels (Andrew et al. 2021). In addition, despite having less forage in solar pastures, lamb production did not differ from lambs grazed in open fields.  Solar sites can also provide foraging habitat for native pollinators and honeybees, particularly during the late summer seasons when pollinator forage is less available.

Although agrivoltaics presents a number of compelling opportunities, there are challenges that need to be addressed to make their installation more widespread and adoptable. Several states (including Oregon) have placed restrictions on commercial solar development to protect farmlands with high-value soil from development, which could complicate the implementation of agrivoltaic sites. Solar panels for agrivoltaics are also more costly than traditional solar panels, as they can require additional settings, space, and other specializations. However, the energy generated by solar panels can help to offset these costs over time.

Meticulous design needs are another challenge. The design of agrivoltaic systems needs to be carefully considered in order to maximize benefits and minimize drawbacks. For example, agrivoltaics may not work in areas that do not receive a lot of sunlight, or with crops that require a lot of direct sunlight. Finally, crops do not always respond predictably to agrivoltaic settings. Producers may have to experiment with crops and reseeding to achieve desired results. As such, producers will have to weigh the potential benefits with the challenges of implementing an agrivoltaic system on their land. Continued research into the response and success of various crops, effective design elements, and regional considerations could help producers decide whether agrivoltaics is right for their operation.

Throughout the Northwest, agrivoltaic systems are being researched for their potential to mitigate greenhouse gas emissions, supply renewable energy, and increase the climate resilience of farms. Though more research is needed to determine the efficacy and feasibility of agrivoltaic systems, existing evidence suggests agrivoltaics could be a useful tool to strengthen food and energy security while increasing the profits, resilience, and diversification of Northwest farms.

References:

Andrew, A.C., Higgins, C.W., Smallman, M.A., Graham, M. and Ates, S., 2021. Herbage yield, lamb growth and foraging behavior in agrivoltaic production system. Frontiers in Sustainable Food Systems, p.126.

Garrett, A., Nebert, L., Homanics, C. 2021. 2021 Potato Variety Trial Results. Oregon State University. Potato Variety Handout (PDF)

This article was adapted from a USDA Northwest Climate Hub article.

Categories: General