Editor’s note: Miles Braxton’s company is Okovate Sustainable Energy. A previous version of this post misspelled the company’s name.

Agrivoltaics — co-locating solar arrays with farming operations — is generating enthusiasm among both farmers and clean energy advocates as a way to promote sustainability in agriculture. 

When implemented correctly, agrivoltaics provides a vital dual income stream for farmers — in solar energy generation, but also as a means of providing an optimal growing environment for compatible crops and herds. The added revenue may allow more farmers to retain their land for themselves and future generations. 

While pilot projects around the country are identifying best practices, not all have been successful, and practitioners say that advancing the technology will require an equitable approach that centers farmers’ needs first.

A discussion during the recent Solar Farm Summit in Rosemont, Illinois, directly addressed the issue, featuring a majority-Black panel of practitioners and service providers. Three major themes emerged during the discussion: maximizing compatibility of solar arrays with existing land use, demonstrating the financial benefits of agrivoltaics, and addressing how solar power can help BIPOC farmers hold on to their land.

“I think one thing that, through our work in this technical assistance, has become very, very clear [is] that people don’t just want to build an agrivoltaics project for the sake of building an agrivoltaics project,” said Jordan Macknick of the National Renewable Energy Laboratory (NREL), who also served as moderator for the discussion. “How does agrivoltaics enable you to take that next step and focus on things like succession planning or farmer training?”

Benefits for farmers

Miles Braxton started his company, Okovate Sustainable Energy, to work exclusively on “farmer-focused” solar development.

Braxton said after several years of developing community solar projects, he “really saw the inefficiencies” of taking farmland out of production for solar projects. “That’s a problem that is just going to keep piling on top of itself until it gets to the point where we can’t develop anything.

“We target crop farmers who are growing a very specific suite of crops that we know works well with our design,” Braxton said.

Cetta Barnhart, owner of Seed Time Harvest Farms in Florida, also cultivates her own plot of fruits and vegetables, and cited her background in food and wellness in promoting the compatibility of solar and agriculture to benefit the bottom line for farmers.

“This is more hands-on of what a farmer can really do in their current practices. If they’re raising cattle, there’s a way that they implement solar with that. If they are having bare land, the pollinator is another way that they can benefit from that,” she said. “So how these solar projects are developed and created for real farmers is still a big conversation to be had.“ 

Ena Jones, owner of Roots & Vine Produce and Café, and president of Community Partners for Black Farmers, cited her dual role as a working farmer and an advocate as an advantage in promoting the potential compatibility of agrivoltaics and cultivation — especially for Black farmers.

“We advocate and we also lobby for farmers at the state level for the state of Illinois and the state of Georgia. And I’m here to kind of segue to help farmers understand … how different solar opportunities can help them with production on their farms, and be an asset to the production on their farms. And also, to help solar developers understand farm[ing],” Jones said.

Noting that solar projects can help cut energy costs, Jones said “Energy use is one of the farmer’s [major] expenses outside of diesel, and of course seed. So, if they can reduce that cost dramatically, even by a third, that would impact their bottom line in revenue extensively. It is very important, especially for BIPOC farmers, to be ushered into this technology so that they won’t be left behind in the process.”

Making connections

Agrivoltaics can be a valuable tool to reduce overall costs, expand potential revenue – or both – as a means of promoting optimal use of farmland. A both-and approach can work to address what is often an inherent tension between the best use of large, flat plots of land for large solar arrays – parcels that also frequently comprise some of the richest soil for cultivation. 

For example, the 180 MW Madison Fields project in Ohio represents a test ground for large-scale agrivoltaics – farming on 1,900 acres between the rows of a utility-scale solar array. One of the project’s focuses is determining which crops and herds are the best prospects to coexist with large-scale solar developments.

“People have a lot of questions with regard to energy development going forward in this state … Finding a balance where you can do a number of things on the same ground — in this case energy production as well as agricultural production — is obviously huge,” Dale Arnold, director of energy policy for the Ohio Farm Bureau told the Energy News Network in July.

Macknick highlighted another project where NREL and Clean Energy to Communities (C2C), along with the Black Farmers Collaborative, worked on a proof of concept project which incorporated solar panels on a demonstration farm cultivated by Barnhart that features citrus trees, leafy greens, and other produce.

“I had already looked into doing solar on my property and was just looking at it to have solar as the backup,” Barnhart said. “But when we started talking as a team and then we found out about the agrivoltaics portion [and] how that can be incorporated into farming, it really brought forth a bigger and better opportunity to not just benefit by having it but also sharing that with other farmers,” Barnhart told NREL in 2023.

Mike DellaGala of Solar Collective said taking a farmer-centered approach can also be beneficial to product and service providers.

“I think a lot of the conversation … has been the difference between farmers and developers, and how we are or [are] not communicating and getting projects over the finish line or not. And I think… if you’re farmer-first or farmer-centric, I think that’s the way to success for everybody… allowing [farmers] to dictate a lot of the project details has been really successful for us. And it makes our job easier, frankly,” DellaGala said.

A farmer-centric and collaborative approach is especially vital in ensuring equitable access to the benefits of agrivoltaics for BIPOC farmers, Barnhart said.

“I stand in the gap somewhat between having conversations with [BIPOC] farmers and having conversations with project developers because you need someone in the middle. I’m a community advocate. I hope there are more of us in the room than not. They have to be in place in order to bridge the conversation as to how this really works well in real-life time,” Barnhart said.

Braxton cited the need to rein in the power of utilities, which he says frequently raise roadblocks to community-level projects to protect their own interests. 

“Utilities have too much power. They have too much money to lobby. They don’t want you to sell power back to your community because [of the impact to] their own rates that they can control. So that’s a risk. The root of those problems is that here in the U.S. … we have 50 little countries [states] that make up their own policies and do their own thing… I think there needs to be a policy to incentivize solar to be developed innovatively. I don’t think policy makers at the state level understand the importance of that,” Braxton said.

Jones noted that policy change will likely be driven by farmer demand, which by extension benefits the larger community.

“In my opinion, once the farmers understand [how solar can] help them on their farms, I can’t say this enough, they will force politicians to comply. The money will be there; the funding will be there. But the engagement needs to happen. It desperately needs to happen,” she said.

Land retention for BIPOC farmers

Loss of land –through racism and other factors, has long been a contentious topic among BIPOC farmers – and Black farmers in particular. According to a 2022 study, discriminatory federal policies contributed to Black farmers losing roughly $326 billion worth of acreage during the 20th century. In July, the Biden-Harris administration announced a distribution of $2 billion to thousands of Black and other minority farmers, created through the Inflation Reduction Act as a means to begin to address this inequity.

Agrivoltaics may not intuitively track as a relevant strategy for land retention; but Barnhart touted its value, especially for Black farmers. 

“[Black farmers] have lost a lot of land because we just couldn’t afford to keep it… We didn’t just lose land because it was confiscated… What solar does is add an income stream or a reduction in your expenses so that there’s more you can do on your farm and create an opportunity for the next generation. 

“It gives us a reason to keep the land going, and it gives us, in our community, resiliency we are experiencing through our climate change storms. For the families that can have that piece of land, that builds a resiliency to protect them in their neighborhoods, protect their own backyard, and protect the future generations, give the future generations something they can look forward to that makes sense to them. Then we build into something that takes care of our wealth building opportunities, our succession planning, and our look into the future to make a change,” Barnhart said.

How a ‘farmer-first’ approach could lead to more successful agrivoltaics projects is an article from Energy News Network, a nonprofit news service covering the clean energy transition. If you would like to support us please make a donation.

Research underway at a Madison County solar farm promises to shed light on how well multi-use farming can work at a large scale. The answers will help shape best practices for future projects, while addressing some concerns raised in ongoing debates over siting large solar projects in rural farm areas.

Spread across more than 1,900 acres, the 180 MW Madison Fields project will be one of North America’s largest test grounds for research into agrivoltaics — essentially farming between the rows on photovoltaic solar projects.

As farmers seek to lease land for solar arrays to diversify their incomes, the practice could help them maximize their income and fend off opposition from critics concerned that solar development will take prime farmland out of production.

Some farmers have also said the revenue from clean energy can help keep their farms operating amid pressure from housing developers. A recent report from the American Farmland Trust says Ohio could lose more than 518,000 acres of farmland to urban sprawl by 2040.

That number dwarfs the roughly 95,000 acres for certified and other projects noted on the Ohio Power Siting Board’s most recent solar case status map. 

Yet solar projects generally deal with big chunks of land at once, while urban sprawl happens bit by bit over time, said Dale Arnold, director of energy policy for the Ohio Farm Bureau. Helping people understand and appreciate that is “absolutely huge,” he said.

Savion, a Shell subsidiary, developed the Madison County project, and it began commercial operation on July 11 with Amazon as the long-term buyer for its energy. Yet work began much earlier this year to set up the site for research by Ohio State University scientists, Savion’s Between the Rows subsidiary, and others.

“People have a lot of questions with regard to energy development going forward in this state,” particularly when it comes to taking land out of use for agricultural production, Arnold said.

Yet today’s industry continues to shift away from coal to a diversified portfolio of natural gas, nuclear, hydropower, wind energy, solar energy and other types of generation. Forecasts also show there will be growing demand for electricity by mid-century, he said.

“Finding a balance where you can do a number of things on the same ground — in this case energy production as well as agricultural production — is obviously huge,” Arnold said. If agrivoltaics is to become more than a buzzword, though, both farmers and solar project developers need to work out best practices.

One big issue is what crops can work well for large-scale utility projects. Compared to most solar farms projects in Eastern and Piedmont states, utility-scale solar projects in Ohio and other Midwestern states can spread across 1,000 acres or more, Arnold said.

“You hear a lot about produce and specialty crops,” for example, said Sarah Moser, Savion’s director of farm operations and agrivoltaics. But raising them is “hard to do on 1,000 acres.”

Hay, you!

Moser and Ohio State University researchers think forage crops like alfalfa and hay hold promise. Operations can be scaled up for large areas, said Eric Romich, an Ohio State University Extension field specialist for energy development. And the crops wouldn’t grow too tall amid the panels.

“We also wanted something that we felt had the potential to be economical,” Romich said.

Two 2023 reports by Ohio State University Extension researchers found raising hay and alfalfa between rows of solar panels was feasible and that the harvest’s nutritive value was good. But that small-scale work at the Pigtail Farms site in Van Wert County used data from only a few test plots and controls, which is an important limitation, Romich said.

Work at Madison Fields will now test whether similar results can be achieved at large scale. Part of a $1.6 million grant from the Department of Energy will help pay for that work over the course of four years.

Other research will test how well plants do in sun versus shade, Romich said. That matters because some portion of the land among solar panels will always be shaded.

Researchers planted the crops on test fields and control areas this spring, with an eye toward starting to collect data next year. “Forages are quite temperamental in terms of trying to get them established,” said Braden Campbell, an animal scientist at Ohio State University who is also working on the project. The team has found compacted soil around the solar panels, “but we are relieved to see that the seeds that we put into the ground are growing,” he said.

Moser plans to work with other crops, too. Soybeans are one example. They were already used as a cover crop before alfalfa and hay were planted. Soybeans can also work into a crop rotation when forage crops need to be replanted every few years.

“The market is there for it, and it does well” as a hardy crop which can also loosen soil and restore nutrients to it, Moser said, adding that local communities have expressed interest in the crop as well.

Send in the sheep

Other work at Madison Fields will explore complementary grazing. The goal is to harvest the forage crops as efficiently as possible. But there will still be a need for vegetation control under and around panels and other infrastructure, said Campbell. So, after harvesting, sheep will go to work.

“To me, that’s three commodities that we can get off one unit of land,” Campbell said: Solar panels will produce electricity. Hay and alfalfa growing will provide a crop. And the land will help support sheep, which in turn can produce meat, milk and fiber.

Other solar farms already use or plan to use sheep for vegetation control. But “there is a big difference” between using sheep to keep plants under control and relying on that for their nutrition, Campbell said.

Studies will need to test the health of sheep that do complementary grazing, compared to other sheep. Other questions include finding optimal grazing rates of sheep per acre, as well as other logistics. But first, the forage needs to establish good roots so it can withstand the pressure of grazing.

Tractors and more

A third bucket of research questions under the Department of Energy grant will focus on farm equipment. Tractors and other farm vehicles need to fit between the rows with their attachments. There’s been a trend in the agricultural sector toward wider equipment, which can cover more ground quickly but may not fit between rows of solar panels, Moser said.

“But a lot of farmers still have smaller equipment,” Moser continued, because some parcels aren’t appropriate for wider machinery. Maneuvering 15-foot-wide equipment works fairly well, and 17-foot and even 20-foot widths can still work. 

“I could get my 20-foot drill in there,” Moser said. “I just have to be careful.”

Arnold speculated that some companies may develop special equipment whose attachments can fit under solar panel rows more easily. Other possibilities could include raising panels or even feathering them when agricultural equipment is in use, he suggested.

Farm equipment doesn’t just need to go down an alley between two rows of solar panels. It will also have to turn around at the end to go down another one, Arnold said. So, there needs to be an adequate turning radius, without cables blocking farm vehicles’ paths. Poles, stands, and other equipment also can’t block the path of the farm equipment, he said.

The research can help guide the design of future solar projects to be “hay-ready” sites, Romich suggested. At the same time, agricultural operations shouldn’t jeopardize the safe and efficient operation of a solar facility. “It’s an operating power plant,” Romich said.

Arnold has additional questions about infrastructure needs: What facilities will be necessary to dry, bale and store forage? What facilities will other crops need? And how will they be trucked out to markets?

Likewise, what equipment and facilities will be needed for any sheep kept on site?  That includes paddock fencing, water, and so forth. And where will their caretaker live? 

“You’re going to have to have people there full-time,” Arnold said.

Precision agriculture

The Ohio State researchers, Moser, and others also wonder how well precision agriculture can work with solar farms. The term refers to methods that rely on technology and data to guide farmers’ work. The range of technologies includes remote sensing of field conditions with drones, in-ground sensors, automated weeders and more.

The big question is which precision agriculture technologies can work well for crops planted between rows of solar panels as they generate electricity.

It’s unclear what any of the studies will show until data has been collected and analyzed, Romich said. By the end, he feels the work will provide a better understanding of what will or won’t work.

Economics questions about business models, contractual arrangements and more also must eventually be worked out, Arnold said. At the end of the day, farmers will need to make a profit if agriculture is to successfully blend with solar projects.

“The possibilities are limitless, really,” when it comes to business arrangements, Moser said. “My motto is always, ‘farmers figure it out.’ And if we work with them, we’ll figure…out how to do this with best practices.”

Large-scale Ohio research project to explore how solar and farming can co-exist is an article from Energy News Network, a nonprofit news service covering the clean energy transition. If you would like to support us please make a donation.

A Massachusetts incentive program for projects that blend solar energy and agricultural production shows signs of finally gaining momentum after a slow rollout that has at times frustrated solar developers and farmers alike. 

In 2018, Massachusetts became the first state to offer financial incentives for “dual-use” or “agrivoltaic” solar projects built above active agricultural land. Since the launch, however, just three projects have gotten up and running. Another eight have qualified for the incentive but not yet been built. 

“It’s really frustrating that we’re not further along,” said Jake Marley, manager of Hyperion Systems, a solar developer with a specialty in dual-use projects. “But the conversation is growing. It’s on that precipice of gathering more and more speed.” 

Supporters of the concept say it has the potential to simultaneously alleviate two problems: the need to build more renewable energy facilities to reduce greenhouse gas emissions and the need to preserve agricultural land, especially small, local farms. 

Massachusetts is aiming to install 3,200 megawatts of solar capacity through a state incentive program at a time when farmland faces growing development pressure. 

“We want to see as much of that as possible developed in a way that’s supporting farms and keeping farms in operation,” said Ethan Winter, Northeast solar specialist with the American Farmland Trust.

In the past, building solar on farmland has generally meant taking fields out of production, replacing crops with solar panels. Dual-use developments, however, call for solar panels built at a significant height above the ground – Massachusetts policies call for a minimum elevation of 10 feet – and spaced farther apart than in conventional arrays. The added space under and around the panel is intended to allow in enough sun to grow crops for harvesting or for animals to graze.

Solar developers and other experts familiar with the Massachusetts program attributed the low adoption rate to a combination of factors. They include a lack of familiarity with the concept among farmers, as well as the state’s relatively strict definition for which projects qualify, which some say is too narrow and conservative. 

“They’re being very careful about how they’re qualifying projects,” Winter said.

Hard to predict outcomes

The program’s rules also had to be tweaked several times to answer questions and smooth out issues that cropped up as the first projects rolled in. While that process was necessary, developers say, it also made it more difficult to reliably plan and budget projects. 

The state solar incentive program has allocated 80 megawatts of its capacity to agrivoltaic developments, providing a higher incentive rate to these projects. The rules require solar panels to shade no more than 50% of the growing area and have strict rules regarding elevation. These guidelines apply regardless of a field’s soil type, what plants will be grown, or whether the land will be used for crops or grazing. 

A better approach might be to focus less on prescribing the specifications of the array and more on outcomes, Winter said. Some places in Europe, for example, have a production threshold that requires dual-use farmland to achieve a certain percentage of its previous productivity.

The novelty of dual-use arrangements can make it tricky for farmers and developers to get a reliable handle on how a new system will work. It can be difficult to predict results in a system as complex as farming, said Dwayne Breger, director of the Clean Energy Extension at the University of Massachusetts Amherst. Variations in crops, soil type, and farming techniques can all change the outcome. And changes in weather patterns from year to year mean the results from one year offer only limited information. 

“There’s an issue with regard to the uncertainty,” Breger said. “It’s hard to come up with definitive information because there’s so many parameters.”

There is also a lack of widespread understanding about dual-use strategies among farmers, Marley said. Farmers operate on tight margins, so taking a leap into a new approach can be daunting without more familiarity with dual-use and its results. And so far there are only a few examples to look to in Massachusetts. 

“Once there are more results, I think there will be more acceptance,” Marley said. 

Early projects help generate interest

Despite these obstacles, it is widely agreed that progress is accelerating in the dual-use space.

Breger helps the state review predetermination applications for the dual-use incentive, a step that helps developers spot potential problems and work them out before a formal application is submitted. Over the last few years he has seen an uptick in the number of these predetermination requests coming through. In the last few years, he said, there have been roughly 30 projects that have completed this early review and there are another dozen in progress. 

The frequency of rule changes has also leveled out, leaving developers with a much better ability to plan projects, said Nick d’Arbeloff, vice president of commercial business for SunBug Solar.

“They polished the policy in a good professional fashion,” he said. “We can now build a system with good confidence that everyone understands how it works.”

The dual-use projects that are operational in the state show promise. In western Massachusetts, Nathaniel Tassinari worked with SunBug to build a 250-kilowatt array on the family farmland he owns in the town of Monson. The project, a community solar development dubbed A Million Little Sunbeams, came online in 2020. The system uses a single-axis design and panels that track the sun throughout the day. The array is elevated above fields where the farm grows hay as fodder for dairy cows. 

So far, the panels are outperforming the modeled expectations by some 15% and there has been no noticeable impact to the hay, Tassinari said. 

“We can’t really see a discernible difference between underneath and not underneath,” he said.

The project is already serving as inspiration for others interested in the concept. Tassinari estimates he gets about 100 “solar tourists” each year, many of whom are solar developers or farmers trying to get a better feel for how the idea works in real life. 

The concept is also gaining traction outside of Massachusetts. The largest dual-use development in the country, a 4.2-megawatt array erected above blueberry fields, debuted in Maine last year. New Jersey has launched a dual-use pilot program and conversations are heating up in states like Pennsylvania, New York, and Illinois, said Iain Ward, founder of agrivoltaic consulting company Solar Agricultural Services. 

In 2020, the U.S. Department of Energy awarded $7 million in grants to four projects across the country investigating aspects of combining solar panels and active agriculture. Breger’s team at the University of Massachusetts was awarded $1.8 million to conduct ongoing research at eight pilot sites, including the country’s first solar installation over a cranberry bog.

Current climate and economic conditions may also help push more farmers to consider agrivoltaics. As hotter, drier summers become more common, the shading provided by the panels might actually be beneficial to some crops, Breger said. At the same time, rising fossil fuel and electricity prices could make solar energy even more attractive than it is already, D’Arbeloff noted. 

And agrivoltaics advocates are determined to push through the remaining obstacles, Ward said. 

“We’re not letting it fail,” he said. “We’re pushing the envelope on acceptance of this.”

After slow start, Massachusetts sees more interest in incentives to mix solar with farming is an article from Energy News Network, a nonprofit news service covering the clean energy transition. If you would like to support us please make a donation.

Some of the world’s most iconic bridges — the Golden Gate and Brooklyn Bridge, for example — share a design principle: They’re suspended, using a web of vertical and horizontal cables to string roads and railways across landscapes. 

Now, a renewable equipment provider with experience in the wind industry is applying the engineering concept to solar projects. Oregon-based Rute Foundation Systems is testing a system that rigs panels 9 feet above the ground using steel cables. The company’s design is aimed at a growing market for dual-use solar, which combines projects with agricultural uses like planting row crops or pollinator-friendly flowers. 

“It really started with the idea of using more efficient and modern bridge technology to affect other civil projects,” said David McFeeters-Krone, the company’s business development advisor. “This is typical for engineers. You see a situation that looks inefficient, and then you wonder, ‘Could it be done a better way?’”

Rute engineers devised the technology on the back of a napkin just 18 months ago. It’s newly out of the prototype stage, but the company hopes to deploy it at dual-use projects on cattle ranchlands, where grazing activities could require highly elevated panels. The company piloted the technology at an installation in North Dakota with support from the Department of Energy. Now Rute is tinkering with the design at a public-private innovation and research station in Oregon and working with a team from Oregon State University to study how animals interact with the structure.

The technology aims to make dual-use projects more feasible by reducing their costs. Today, combining solar and agriculture comes with a price premium; installing projects high enough off the ground and with enough space in between rows to grow crops or graze animals means more steel to support the solar panels. Building dual-use projects can increase installed costs by a wide range, anywhere from 7 to 80 cents per watt, according to the National Renewable Energy Laboratory. Rute says its product, called Suntracker, reduces steel costs by about a quarter from more traditional dual-solar configurations.

Reducing solar costs is “critically important” in general, but that’s particularly true for dual-use solar, which is still viewed as somewhat experimental, said Dwayne Breger, who directs the clean energy extension at the University of Massachusetts Amherst. 

“The most difficult economic thing for farmers is risk,” said Breger, who previously led the renewable energy division of Massachusetts’ Department of Energy Resources.

Dual-use solar, or agrivoltaics, as it’s sometimes called, is still a relatively small portion of the overall solar market. Jordan Macknick, who heads research on low-impact solar projects at the National Renewable Energy Laboratory, estimates there are about 500 such projects nationwide, making up roughly 10% of large-scale projects installed in the U.S. The lab has studied agrivoltaics since 2015. Their Department of Energy-funded research has shown that such projects, if designed properly, can benefit both landowners and solar companies. 

“We’re very confident any crop you can grow outside of a solar array, you can grow within a solar array,” Macknick said. Perhaps more important now, he said, is whether developers can find farmers who want to offer up land for those types of projects and whether growers can make a living that way. 

Prime farmland — flat, sunny, and connected to roads — has become increasingly enticing for solar developers as clean energy expands. That’s created tensions in communities where agriculture has long been a way of life. Dual-use solar has the potential to become a type of “compromise” between those two land uses, Macknick said. In its next phase of research, the lab is working to expand the list of entities conducting dual-use solar research. The lab has also built resources, like a financial calculator, to help more landowners and solar companies learn about agrivoltaics. 

The field is “rapidly expanding,” according to Macknick. But Rute is focused on a use that’s gotten comparatively little attention. Many agrivoltaic projects now designed for grazing use smaller animals, like sheep, according to tracking from the National Renewable Energy Laboratory. Rute’s strategy would go after untapped ranchland “that no one’s even thought about yet,” said Doug Krause, the company’s chief executive officer. If the technology proves compatible, that would be a significant advantage compared to other solar technologies, which are generally unsuitable with land used for cattle, Macknick said.    

Rute’s system can also be installed on uneven ground. It may cause less disturbance to land than more traditional dual-use setups, said Sujith Ravi, who studies agrivoltaics and directs the environmental science program at Temple University. Scientists are still working to fully understand the benefits and tradeoffs of agrivoltaics projects. Because each site is unique, Ravi said more research is needed to understand how solar and agriculture interact over a wide range of geographies. 

“There’s a lot of potential,” Ravi said. “Research happening all over the world in the context of energy and agriculture colocation is [working] to find what benefits should we target in different locations.”

The company will also need to demonstrate its cables and panels placed high in the sky can withstand strong storms, said Breger. 

Rute got its start about seven years ago, building modular foundations for wind turbines that it says use 50% to 75% less concrete than traditional installations and take just a few days to install. Traditional turbine foundations may require excavation to install and it can take weeks for the cement to cure. 

For now, Rute is shifting its focus to solar and Suntracker. Using tests at its installation in Oregon, Rute has reengineered lighter racks to hold solar panels and shifted how it places the cables to support them, lowering the number of poles required to support the installation. The company is now experimenting with ways to reduce the amount of steel per kilowatt to further reduce costs. It’s also started planning a project with an Oregon rancher that’s expected to begin construction this summer. 

Much like the wider field of agrivoltaics, Breger sees Rute’s solution as innovative, but worthy of more tests.

“We need to have solar. … Solar is going to take up land. And if we can get this dual use out of it, then there’s a lot of appeal to that,” Breger said. “Exactly how that works out and [gets] optimized, there’s still a lot of innovation, a lot of data and science that needs to be collected.”

Oregon company borrows concept from iconic bridges for elevated solar arrays is an article from Energy News Network, a nonprofit news service covering the clean energy transition. If you would like to support us please make a donation.

Drought and extreme heat in California’s Central Valley in recent years has meant shortages of tomatoes, particularly “processing tomatoes” used for sauce and ketchup. And such conditions are only expected to get worse with climate change.

Researchers note that the relatively nascent field of agrivoltaics — growing crops below and between solar panels — could offer help to the country’s billion-dollar-plus tomato industry. 

Shade provided by solar panels can help conserve water, create humidity, and lower temperatures that can become too much even for heat-loving tomatoes. 

An August paper by the National Renewable Energy Laboratory surveying agrivoltaic research sites across the country noted that on average, tomato yields doubled compared to non-agrivoltaic sites, whereas other crops like wheat, cucumbers, potatoes and lettuce showed negative impacts. 

When it is too hot, tomatoes will abort the development of fruit from flowers since the plant senses that the fruit won’t flourish. Solar panels cool the air down enough to avoid this process, research has shown. And most importantly in a place like California, where the vast majority of the nation’s tomatoes are grown, solar panels can mean significantly less irrigation is needed. 

Florida, the nation’s second-largest tomato producer, typically has plenty of rain. But even there, climate change means temperatures are climbing and drought has hit parts of the state. 

At the University of Arizona’s Biosphere 2, cherry tomatoes doubled their yield when grown under solar panels, as noted in a 2019 study published in Nature. 

“They got plenty of light, plenty of water, and the temperature stress was brought down just below that threshold so they could fruit through the summer and get an extra month of production, and more production per plant,” said Greg Barron-Gafford, lead author of the paper and associate professor in the School of Geography and Development at the University of Arizona. 

Multiple benefits 

Barron-Gafford found that not only do solar panels cool the air during the day, but they also warm the air at night — a benefit for tomatoes and other crops in desert climates like Central California and Arizona where temperatures can plummet after dark. 

Even as the solar panels created cooling shade for the plants during the day, Barron-Gafford also observed a mutual benefit for the photovoltaic panels. Solar arrays are less efficient at generating energy when they are especially hot, and plants growing below panels create a cooling effect on the panels thanks to their transpiration. 

Tomatoes often grow to about 5 feet high, so they can fit under solar panels that are elevated to 6 feet — taller than most commercial arrays but standard for agrivoltaics. Tomatoes are often harvested by hand, and Barron-Gafford’s research in Arizona noted that agrivoltaics could benefit farmworkers, with preliminary research showing skin temperature could be as much as 18 degrees F lower working under the shade of panels. 

While processing tomatoes are grown in vast fields, many whole tomatoes sold in stores are grown in greenhouses. Researchers said that growing tomatoes under solar panels could mimic the conditions of a greenhouse in some climates, and energy from solar panels could also power on-site greenhouses. 

“When the average person goes to the supermarket and sees tomatoes still on the vine, those are usually hot-house-grown tomatoes,” Barron-Gafford said. “So how do I use renewable energy to offset the immense cost it takes to keep a controlled environment like that cool?” 

Oregon observations 

Researchers at Oregon State University examined tomato cultivation with agrivoltaics in a cooler climate for a 2021 study. They found mixed results that bolstered the idea that tomatoes are ideal agrivoltaic candidates in hot climates where most commercial production is done, but not a fit for small farmers in cooler climates. 

“They’re one of the crops that would be an excellent choice in a warmer, more arid environment, whereas if you move to the northern USA, the Midwest where sunshine and temperatures are already edgy for tomatoes, it would push them out of contention,” said Chad Higgins, Oregon State associate professor of agricultural sciences. “For any crop, you have to consider the current climate and what agrivoltaics will do to that climate.” 

In the Oregon State research, tomatoes were planted under solar panels, between rows of solar panels, and in a separate area as a control. The solar array was close to 500 kilowatts total, and each group had two plots with 40 tomato plants in each. 

The soil and air temperatures were significantly lower in the plots below the panels, compared to the between-row plots and control. The soil temperature under the panels was a full 5 degrees Celsius lower than the between-rows and the control. The sunnier control plots’ tomato plants yielded the most fruit. But the control plot used more water than the other plots, even in a relatively cool climate — an effect that might be amplified in a hotter place. 

The researchers concluded that agrivoltaics offered the opportunity to “trade a reduction in yields for reductions in water use.” The study notes that using water more efficiently may not matter in a place with lots of rain like western Oregon, but “could be critical in areas which are currently water stressed and expect to become more water stressed in coming years.” 

Hadi Al-Agele was the lead author of the Oregon State study as part of his doctoral research. He lamented that their tomatoes suffered when “it became so cold and rainy.” But he is now working in his home country of Iraq, where there is blazing sun but little solar energy. He would like to see agrivoltaics take off there, providing clean energy and helping crops survive the heat. 

Advancing science 

The Arizona and Oregon researchers said that tomatoes are a good fit for agrivoltaic studies, providing insights that can also apply to other crops. Barron-Gafford noted that there are generally three types of specialty crops — leafy greens, tubers like potatoes, and fruiting plants like tomatoes and peppers, hence agrivoltaic studies try to include examples of all three. 

“Tomatoes are a really well-studied plant,” meaning agrivoltaic results can be compared to other literature, Higgins added. “We could have studied ginseng, which is an interesting choice because it grows slowly and is only hand-harvested, and needs 80% shade — the agronomics match really well. But there’s just not as much literature about the plant physiology of ginseng.”

Whether agrivoltaics really are adopted by the tomato industry depends in large part on the economics of meeting the needs of both solar developers and farmers. Elevating solar panels higher to accommodate tomatoes underneath means extra costs, and machinery used to pick and plant tomatoes on many large farms might not work in concert with solar panels.  

The Oregon State researchers studied tomatoes under tilted solar panels that were not ideal for planting and harvesting tomatoes — they had permission to work in a solar array that was not designed specifically for the experiment. 

Higgins described Al-Agele stooping below the panels to prepare the soil with a hand-held rototiller held at an awkward angle, since the panels were only 18 centimeters off the ground at the lowest point. “It was hard,” Al-Agele said. 

“I don’t know of any commercial grower who would grow tomatoes in the fashion we did. It would be too much work — too much hand labor,” Higgins said. “We were doing it for science.”

Cool tomatoes? Agrivoltaics could help California crop, if the economics pan out is an article from Energy News Network, a nonprofit news service covering the clean energy transition. If you would like to support us please make a donation.