Dual-Use Solar in Washington: How Do You Like Them Apples?

Summary by Whitworth University Communications Student Hannah

This is a discussion from the Solar Summit about agrivoltaics and ecovoltaics, which are dual-use approaches to solar energy that integrate agriculture or ecological benefits within solar panel arrays. Max Lambert, the Director of Science for the Nature Conservancy in Washington, introduces the concept, highlighting the potential for land-sharing approaches to mitigate the land use impacts of greenfield solar energy. The panel explores the science, mapping, and modeling of agrivoltaics in Washington state, with a focus on crops like apples, pears, berries, and vegetables, as well as solar grazing with livestock. Addie Candee from American Farmland Trust shares social science research on farmers’ perspectives of agrivoltaics, emphasizing the importance of communication, trust, and policy incentives to promote its adoption. Callum McSherry from Cascadia Renewables provides insights from a solar professional’s perspective, discussing the challenges and lessons learned from an ecovoltaic pilot project at Eastern Washington University. The discussion covers topics such as fire code and ecology, fencing and microclimates, and construction and soil conditions. The panelists also discuss the needs and opportunities for collaboration to deploy these approaches, the role of dual-use approaches in Washington’s energy future, and the potential for integrating solar with cropping systems.

Dual-Use Solar in Washington – Agrivoltaics

By Richard Hartung, Solar Washington Board President

Ecovoltaics, agrivoltaics and the concept of dual-use solar make farmland a potential new frontier for solar energy. Addie Candib from the American Farmland Trust (AFT), Callum McSherry from Cascadia Renewables and Max Lambert from The Nature Conservancy provided insights into dual-use applications of solar for agriculture and energy.

Agricultural Yield can Increase

Max said his organization’s team modeled an integrated solar mapping tool, PVsyst, and a crop physiology tool to take different solar PV Ray designs. They looked at how much energy they produce and how much shade is beneath. They then analyzed how it impacts apple, lettuce, strawberry and other crop quality and quantity. 

Max said sunburn is an apple summer risk in Washington. During the year, there is up to a month of sunburn risk, which is farmers use shade cloth. High density panels and lower density spacing panels ameliorate the sunburn impact.

From the orchardist perspective, solar panels over an orchard offer a good benefit to apples. They are on par with utility scale solar energy projects across this latitude. While they are more expensive than ground mounted solar, they are cheaper than rooftop solar. 

Looking at lettuce statewide, with single access tracking and fixed tilt solar, lettuce should work well. Strawberries are different, though, as they are not shade-happy and don't work as well as blueberries or raspberries. 

Agrivoltaics can reduce heat stress by 30% to almost 100% in apple orchards, depending on the area. The design is more effective in protecting against summer than shade cloth, and they have competitive costs.

“There's definitely potential.”

Agrivoltaics Faces Resistance

“Over the last six years or so,” Addie said, “we've started to do more work in the solar space, in part because we see solar energy development as a threat to our most viable farmland. On the other hand, we also see solar as an opportunity for farm viability.”

Four core solar siting principles guide their work. The first is to prioritize solar on buildings and other areas not well suited for agriculture. Then, they want to safeguard soils and the ability for the land to be used for agriculture in the future, to grow agrivoltaics for both energy production and food production, and to promote equity and farm viability. 

AFT conducted a survey and interviewed farmers and other parties in Washington from February to April 2025. They found that producers in western Washington are more in favor of solar development on agricultural land than producers in eastern Washington. 

About 40% said they had never heard of agrivoltaics or didn't understand it. There's an opportunity to do more education with the agricultural community. 

The ATF team asked producers about their perspectives on solar, showed them photos about agrivoltaics and then asked whether the photos made them more supportive. A majority did start to shift their perspective.

Over half said that they would be willing to host solar panels on their land if they can continue farming under and around the panels. “Farming is integral to farmers’ identity. It's not just a job. It's not just a way to make money. It's a lifestyle. It's a community and a way of being in relationship to the land.” A majority of respondents said they would not change production systems to accommodate agrivoltaics.

Concerns include the way the solar panels look or change the landscape, unknowns around decommissioning, uncertainty about impacts on yields, navigating equipment around solar panels. and uncertainty about how it will impact the soil. 

Communication and trust between landowners and farmers and ranchers, utilities and policymakers, and developers is key. AFT also suggests that Washington State should explore policy pathways to incentivize agrivoltaics. 

Agricultural producers are operating in a very rapidly changing climate, Addie said. They need to be able to adapt to their crop type or system. 

AFT wants to keep land in farming and conserve soil and water resources, to expand the breadth of production systems, and eliminate the potential for program loopholes. They have developed a recommended statutory definition and process for agrivoltaics. 

Testing Agrivoltaics in Eastern Washington

Callum discussed work his organization started doing with Eastern Washington University a couple of years ago, focused on resiliency and microgrid planning. Their project looked at an ecovoltaic system on the campus. The main purposes would be to generate renewable energy, meet decarbonization goals, serve as a research platform, and create an example of good stewardship. There were a series of challenges.

The first was fire code and ecology. There is a requirement for a brush-free area of 10 feet around the perimeter of ground mounted photovoltaic arrays. They had challenges convincing a fire marshal that four-foot-tall dry grass could be categorized as maintained. The determination was that the leading edge of the PV array must be at least five feet above the ground, and native vegetation planted there had to be a maximum of 12 inches high. That distressed ecologists at Eastern Washington University because that is not what Palouse prairie looks like. He strongly recommends engaging the fire marshal early in the project.

The second was fencing and creating microclimates. The requirement was to build a fence to keep students out. Academics said fencing off an area creates a microclimate. Something to be aware of is unintended consequences. 

Challenge three was that construction and soil conditions are unique.

One thing they looked at is how to sequence construction. The goal is to be as efficient as possible to make the systems economically viable and increase deployment. From an ecological perspective, agrivoltaics can destroy ecological growth. Compromise is essential.

Agrivoltaics Surprises

Panelists then addressed a variety of questions. One was what surprised them the most.

Callum said he was very skeptical of agrivoltaics. Prior to this research, it seemed the outcome would be poor solar and poor farming. He was surprised by how many types of crops or yields can be improved. 

Max said some apple orchardists are willing to lose a quarter of yield to do this because they're making nothing off their crop.”

Addie said she was pleasantly surprised by the strong potential to combine orchards and solar. Addie also noted that producers are interested in more collocation such as putting solar panels on irrigation pivot corners or on low feed sheds for animals. There are interesting projects in states where solar panels float on irrigation canals.

Dual Use Solar and Washington's Broader Energy Goals and Energy Future

Max said it is important to look at the scale of the problem for decarbonization, electrification and growing demand. “We're going to need a lot more land. That's coming from natural land or farmland. Without dual use approaches, we're talking about losing farmland.”

Addie said there's an important question of scale. Around the US, there are small-scale and utility scale projects, with little in between. “The challenge is proof of concept.”

Callum said there's space to help mitigate the damage of the large-scale development that is needed to meet the state’s energy goals. 

Downsides of having Livestock and Solar Co-located  

Addie said people feel like integration with sheep grazing and other livestock is the low-hanging fruit. The challenge is that there is a very small sheep industry in Washington State. Sheep don't eat everything under the arrays, so producers still have to mow or apply herbicide. 

Max similarly said Americans don't eat a lot of sheep or sheep cheese, so the issue is building a new market. Also, sheep need water and somewhere else to go after they eat out the property. 

While skepticism about agrivoltaics remains, it appears to be a more promising solution than many people – including the panelists – expected.