Tag Archive for: Solar Grazing

In November, Sabrina Portner from the University of Minnesota presented on her exciting research into growing 14 different forage and grain crops at three different solar sites. The forages and grain were grown in the context of feeding them to the research farm dairy herd. Sabrina and her team looked at how different shade levels affected each crop’s biomass production, as well as the nutritional value of the crops.

This research addresses an important issue: as land availability pressures increase, especially with the expansion of solar in rural areas, the sustainable intensification of agriculture and the need for combining solar sites with agricultural production become more imperative. Their research works towards both goals of food production and clean energy production while providing flexible economic opportunities to farmers.

This Teatime was hosted by Kevin Richardson of the American Solar Grazing Association and Victorian Smart of the AgriSolar Clearinghouse.

Farmers in France are Beginning to Combine Solar Panels and Crops 

“In the Haute-Saône region, in the northeastern part of the country, an experiment is being conducted by solar-energy company TSE. It is hoping to find out whether solar energy can be generated without hindering large-scale cereal crops. Previous attempts to experiment with agrivoltaics have been through smaller-scale projects. But, keen to see if it can thrive on an industrial level, 5,500 solar panels are being spread over this farm in the commune town of Amance by TSE.”  – Euronews 

Solar Grazing Event Helps Kentucky Students Learn about Agrisolar 

“The event was made possible through a partnership between the Kentucky Sheep and Goat Development Office, LG&E/KU, University of Kentucky, Ohio State University, and solar development company Lightsource bp. Students learned about solar technology, seed mix establishment and meeting nutritional needs in solar grazing. Additionally, the release said students were able to tour the LG&E/KU E.W. Brown Generating Station’s solar array in Mercer County.” – The News Enterprise 

Cornell Researcher Hosts EarthTalks Agrisolar Series 

“Niko Kochendoerfer, a postdoctoral fellow in animal sciences at Cornell University, will deliver the talk ‘Effect of sheep stocking rate on ecosystem parameters in ground-mounted solar arrays’ at 4 p.m. on Monday, Nov. 14. The talk, which is free and open to the public, takes place in 112 Walker Building on the University Park campus and via Zoom.”  – PSU 

Rebecca A. Efroymson, Environmental Scientist, Oak Ridge National Laboratory); and Jonathan M. O. Scurlock, Chief Adviser for Renewable Energy & Climate Change, National Farmers’ Union of England and Wales

Solar photovoltaic (PV) power, the most popular form of renewable energy on farms, is being adopted all over the world. Growers and processors of food worldwide have a long history of using the sun’s energy to produce and dry their crops, and solar PV is adding a modern twist to our relationship with the sun. It is no surprise that some of the best locations on Earth for harnessing solar energy are often ideal places for agriculture and horticulture. However, intelligent design for multi-purpose land use can alleviate real or perceived conflicts between energy and food production. Solar modules can shade crops where light intensity is in excess of crop requirements, reducing water evaporation; they can be mounted on agricultural buildings to power farm business energy needs; and they can export low-carbon electricity to meet wider demands for “green” power and the transition to a “net zero” global economy.

We use the term agrivoltaics broadly to describe any combination of agricultural activity and solar electricity production, but outside the USA, the term usually refers more specifically to the intimate juxtaposition of solar modules and agricultural land use. Examples include PV modules mounted at a height of several meters to allow access to land below by farm machinery or large livestock, where they provide shelter from storms or excessive solar radiation, and the integration of solar PV into greenhouses for crop protection.

We caught up with a range of projects across three continents to report upon their objectives and their future prospects.

Around 30% of British farmers have either rooftop or ground-mounted solar energy. The National Farmers Union (NFU) aspires to the goal that every farmer and grower have the opportunity to become a net exporter of low-carbon energy. The falling capital cost of both solar and battery electricity storage has resulted in a growing pipeline of solar installations across a range of sizes, including large 100-hectare (ha) and 1,000-ha solar farm projects, largely independent of government policy support. The NFU advises farmers that solar PV can be deployed across entire fields, as small, ground-mounted installations around field margins or adjacent to farmyards, on farm buildings, and on domestic rooftops. Developers of solar farms are encouraged by the NFU to follow best practice guidelines for multi-purpose land use, combining energy production, continued agricultural management such as grazing, and creation of wildlife habitat. NFU’s strong preference is for large-scale solar farm development to be located on lower-quality agricultural land, avoiding as much as possible the most productive and versatile soils. Roof-mounted solar systems in Britain continue to offer a sound investment, making between 10% and 25% simple return on capital annually at current electricity prices, depending on how much of the generated power is used on-site. At of the end of 2021, about 70% of the United Kingdom’s 14 gigawatts of solar power generation capacity was located in the agricultural sector.

Multi-purpose land use – sheep grazing and hedgerows of natural vegetation around a large (44-megawatt) solar farm near Haverfordwest in the United Kingdom. Photo Credit: Jonathan Scurlock

In the Netherlands, the Symbizon project at Almere, near Amsterdam, has brought together a Swedish energy company with Dutch researchers and a private organic farm to construct a 700-kilowatt solar park with alternating strips of PV modules and rows of crops. Starting in spring 2023, the production of herbs will be investigated, and potatoes, beans, beetroot, broccoli, and grains may be included in this pilot study. Pivoting double-sided (bifacial) solar modules will catch the reflected light from soil and crops.

Nearby in Germany, Goldbeck Solar is an innovator in solar agrivoltaic structures. The company has developed a system of solar PV arches that slide on side rails, allowing farmers to shelter or expose various crops. Typically oriented east to west for maximum solar energy yield, the arches span up to 9 meters, at a height of 2.5 to 3 meters, allowing a degree of control over temperature, humidity, and light. These agrivoltaic modules can also provide shelter for livestock from extreme weather, such as high temperatures and hail. The modules are currently undergoing trials in the four-year Sunbiose project in the Netherlands, which had already succeeded in growing raspberries under the partial shelter of solar PV modules. 

Agrivoltaics are being tested in East Africa, where their shade can reduce heat stress and water loss, and farmer incomes in disadvantaged rural communities may be improved. An experimental facility opened in 2022 in Insinya, Kenya, through partnership with Universities of Sheffield, York and Teesside in the United Kingdom, the Stockholm Environment Institute, World Agroforestry, the Centre for Research in Energy and Energy Conservation, and the African Centre for Technology Studies. Some 180 PV modules, each 345 watts, have been installed about 3 meters above the ground, allowing a variety of crops to be grown under the shade from the strong equatorial sun. Geoffrey Kamadi of The Guardian reports that benefits include improved yields of cabbage, eggplant, and lettuce; a reduction in water loss; and a reduction in high daytime temperatures and UV damage.

Small-scale agrivoltaic development (less than 0.1 ha) has progressed rapidly in Japan, producing 0.8% of the total solar power generated in the country in 2019. Japan has perhaps the greatest number of agrivoltaic farms to date, with more than 120 plant species being cultivated on agrivoltaic farms. The Solarsharing Network provides a catalog of 27 agricultural crops (Solar Sharing for FUN | SOLAR SHARING NETWORK| Solar Sharing Association of Japan (solar-sharing.org) and their light needs. Innovative crop systems include tea, according to Makoto Tajima and Tetsunari Lida of the Institute for Sustainable Energy Policies.

One pilot agrivoltaic project in New Zealand is seeking low-growing flowering plants like alyssum to attract bees and reflect light up to rows of bifacial PV modules. The high energy demand of irrigation systems can benefit from on-farm solar energy. In New Zealand, as in the U.S., UK, and Australia, sheep and other small livestock graze under solar modules, avoiding the need for mowing. As New Zealand reporter Delwyn Dickey notes, the success of such large-scale agrivoltaic systems (i.e., solar farms) may be determined by an insistence upon dual land use during the consenting process and the willingness of solar energy development companies to adopt dual land use.

Clearly, from small-scale intimate mingling of solar PV with agricultural production to multi-purpose land use in the largest of solar farms, the merits of harvesting the sun’s energy twice are appreciated the world over. The outlook for agrivoltaics is bright indeed.

In partnership with Lightsource BP, Texas Solar Sheep grazes over 1,800 sheep on a solar site in Deport, Texas. These sheep are grazed in groups of 50 to 75, 250 to –270, and even 500, making Texas Solar Sheep one of the largest Agrisolar grazing operations in the United States.   

All 1,800 sheep are grazed and managed on one solar site, which has 18 individual pastures. The sheep are grazed year-round on the same site. The area gets maybe one snowfall a year, which is not a huge issue for them, as the solar panels provide good protection from elements for the sheep. The farm may buy one stockpile of hay for the winter if they feel it is necessary as a precaution, but stockpiling food is not a great concern on this operation.  

No mowing duties are required on this site, thanks to responsibly managed, rotational grazing of the sheep. There are many weeds that sheep will not eat, so they must be manually removed. After some time, if those weeds can be removed from the site, then there is no need for mowing or the use of gas or diesel-operated maintenance equipment. Graziers mowed this site four times in 2021 and have not mowed at all in 2022 as of the end of September.  

J.R. Howard, owner of Texas Solar Sheep, says it is important for new graziers to know that the client of this operation is the solar site, and the grazier is providing a service to replace mowing on the site. The sheep-grazing service has been shown to provide significant benefits to the solar site, including enhancing the health of the turf, reducing runoff from rainfall, and providing crucial shade relief to both the grasses and the sheep during drought periods like those seen in 2021.  

Photo courtesy of Texas Solar Sheep

Healthy Turf Prevents Runoff 

The site has realized benefits from preventing rainfall runoff as a result of developing healthy turf. There was hardly any runoff after 3 inches of rainfall, due to the enhancement in turf quality from responsible grazing management, according to Howard. Healthy turf is a result of not overgrazing individual areas and managing proper sheep rotation. The sheep are not allowed to eat to the bare ground, resulting in what is known as a healthy turf that allows the land to capture and hold the water when it rains, resulting in less runoff and other associated issues. Howard said the land is back to looking like “normal land” and not “golf courses.” 

Shade Relief for Grasses and Sheep 

During the drought of 2021, the solar panels provided crucial shading for the grasses and the sheep. The grass between the panels that did not have shade did not do as well as the grasses that were getting shade from the panels. “The shade support really helped a lot,” Howard said.  

Sheep typically feed in the morning and then hang out in the shade during the day, which the panels provide plenty of. Unlike goats and cattle, sheep do not damage equipment by rubbing against it, climbing on it, or chewing on wires as some goats do. The sheep can be comfortable under the panels during the day with little, if any, threat of damage to equipment. 

Rotational Fencing  

One challenge that the operation has dealt with is constantly rotating the sheeps’ pasture, which needs to be consistent and on schedule. Limiting grazing to smaller areas more often, as opposed to one large area less frequently, is ideal. However, this approach requires fencing that must be moved regularly. The operation requires “cross fences” to break large blocks of land into smaller pastures. Moving fences is one of the most consistent tasks of the operation, but it is manageable.

 

Photo courtesy of Texas Solar Sheep

Breeding for Agrisolar Conditions 

The solar company allows the sheep owners to breed lambs when they want. The sheep live on the solar site from birth until they are sold or pass away. The sheep are also checked by a veterinarian at various times during their life cycle on the site. Owners breed sheep on site, to “get the ewe they want,” Howard said.  

This selective breeding process is an attempt to breed a sheep genetically superior in parasite resistance than previous generations of sheep. These sheep would be specifically resistant to parasites during the lamb phaseand the lactating ewe phases of their life, which are often when farmers struggle with parasites infecting their sheep. Due to the selective breeding process on this site, the sheep will be more resilient to the conditions they experience in Texas, which includes hot temperatures and prolonged, wet conditions. 

Although Dorper sheep, which originated in South Africa, are genetically capable of handling hot temperatures, they are being breed with Katahdin and St. Croix to enhance their genetic capabilities further—making them the most ideal sheep for agrisolar operations in these climate conditions. 

Photo courtesy of Texas Solar Sheep

What New Graziers Should Know 

New graziers should know that this is not a grazing lease with the solar company but, rather, a grazing service business. As a service business, people with sheep will have a customer that they are providing a service to. This requires graziers to spend more time on-site where they can correct issues quickly. If sheep get out of the fenced paddocks, graziers can get them back to their assigned areas quickly. Sometimes sheep pass away and need to be removed as quickly as possible. Being on-site allows for that. If sheep are sick, they can be attended to quickly. The grazier can also ensure that sheep have constant access to water.  

The solar company also benefits from having Texas Solar Sheep staff on-site regularly. “We are out there more than the solar folks, so we see issues for them, too. It has been an extra set of eyes for them on the solar equipment, so that has been a significant help for them, as well. If they see downed panels, damaged wiring, or even fires, they can report it quickly and get it taken care of,” said Howard. “There is a public eye on this stuff, so we want to make sure we are doing it right.”  

Howard stated that grazing is the future of utility-scale solar. It is important that the first few big sites get it right. With great partners like Lighthouse BP, Texas Solar Sheep has been able to scale up its operation, and is planning for larger sites for the future, meaning more sheep on more solar sites. 

Howard said the family farm had about 300 ewes and having the opportunity to partner with Lightsource BP has allowed them to have extra land to graze and scale up their operation. “We’re not a big landowner, and this allowed us to scale up a lot, to 1,800 ewes.” 

In August 2022, ASGA Board President Jonathan Barter and “The Grass Whisperer” Troy Bishopp joined us for a lively discussion on how to plan grazing management. 

For their follow up, Jonathan and Troy led a discussion focused on planning for larger grazing operations. They invited graziers and ASGA members JR Howard, Josiah Fleury, and Dennis Bauman to discuss their experience with grazing operations on large sites. The conversation was wide-ranging and dug into the practical components of how you plan grazing at scale as well as regional differences, including between smaller-scale operations in the Northeast where utility-scale grazing is less common and Texas and other states where utility-scale grazing is more the norm.

Here are some of the broader topics they covered:  

  • Their roles in site design and layout
  • Challenges they’ve encountered in developing management strategies
  • Planning for economic considerations and contract compliance
  • Water supply, mowing, and fees

Hosts: Kevin Richardson (ASGA) and Carl Berntsen from AgriSolar Clearinghouse / NCAT

This Teatime is part of a series co-hosted and sponsored by the AgriSolar Clearing House team. We thank them for their generous support and for adding their expertise to the Teatime events!

Dr. John Walker (TAMU AgriLife Research) and Haley Gosnell (who runs joined us to discuss the extensive practical targeted grazing knowledge he and his team have collected from graziers across the U.S. and Canada. John is a range livestock and wildlife specialist who focuses on vegetation and diet selection for grazing ruminants.

From 2021-2022, he and his team conducted a survey of over a 100 targeted grazing serviced providers in the U.S. and Canada, as well as parallel focus groups, on lessons learned from their experiences with targeted grazing. The survey covered a number of different landscapes (from rural to urban and private to public) and variations in vegetation, grazing scales (small to large), and grazing season lengths. This was part of an effort to update the American Sheep Industry’s 2006 Targeted Grazing Handbook.

John discussed the results of the survey and its insights into targeted grazing.

Hosts: Kevin Richardson (ASGA), Caroline Owens (ASGA Board Member), and Carl Berntsen from AgriSolar Clearinghouse / NCAT

This Teatime is part of a series co-hosted and sponsored by the AgriSolar Clearing House team. We thank them for their generous support and for adding their expertise to the Teatime events!

About the Speakers:

Dr. John Walker, Professor, Range Specialist: I am a Professor and Resident Director of Research at the Texas A&M AgriLife Research & Extension Center in San Angelo, Texas. My responsibilities include providing leadership to a multi-disciplinary team of six scientists that develop new technologies for increasing the efficiency and sustainability of range livestock and wildlife production. My research interest relates to developing new technologies for modifying diet selection of grazing ruminants. It has long been known that livestock grazing affects the botanical composition of vegetation communities. By avoiding some plant species and preferring others, livestock provide a competitive advantage to plants that are avoided, which allows them to increase and often dominate a site. Grazing systems were developed to help overcome this adverse effect of selective grazing on rangeland composition. I am interested in directly modifying the grazing habits of livestock through selective breeding, nutritional interventions and learning. In conjunction with this research, I have developed near-infrared spectroscopy calibrations that use fecal spectra to predict the botanical composition of diets.

Lake Pulaski is an agrivoltaic solar power plant site developed by Enel Green Power that spans over 68.2 acres in Buffalo, Minnesota. This site is one of 16 developed for the Aurora Distributed Solar LLC project in 2017, supporting pollinators, grazing, and an apiary. The layout consists of 34,668 panels at 315 watts each, spanning over 500 individual arrays. The total plant system size is 10.92MW (dc). Each panel has a SolTech single, horizontal axis tracker to follow the sun path and optimize production. This tracker was chosen over the more standard axis-pole trackers due to their ability to allow curves in the array installation to accommodate the rolling landscape. The developers strived to install the system with minimal land disturbance to maintain the landscape and reduce excavation, thus allowing the panels to move with the rolling hills. Panel height was design to be approximately 2.5 fee from the ground at the maximum tilt angle of 45o to allow grazing sheep to pass under without harm to sheep or panels. This sets the total height of each array at a maximum of 10 feet.

Showing how the panel height is appropriate to allow for sheep to graze under panels.
Solar tracking system with grazing sheep

The landscape is grazed once a year near the end of September for one month to reduce the need for mowing, save on labor and gas, and maintain a healthy soil chemistry. Graduate students at Temple University in Pennsylvania are conducting studies on the benefits of grazing, such as soil composition, a reduced mowing, and a reduction in spraying for weeds. Eight of the 16 Aurora project sites are grazed for research purposes. Occasional mowing is required if the area has a high-growth year. Minnesota Native Landscapes (MNL) developed the original native seed profile to help promote pollinator activity under the panels. The final seeding was completed by Westwood Professional Services. MNL also maintains the pollinator and native landscape. Bare-grounded spraying is used to kill off unwanted invasive species, such as thistle. These areas are then fenced off to prevent wildlife and sheep in the area. Soil samples are taken from sprayed and mowed areas for research. Lake Pulaski also promotes the bee population by allowing bee farmers to move their hives next to the site to help pollinate the area and grow healthier bees.

Dustin Vanesse from Bare Honey holds up a hive panel covered in honey bees.

Lake Pulaski is not without maintenance needs. The enormity and complexity of the site requires technicians, plant experts, landscapers, and sheep farmers to ensure that the site function as designed. Enel Green Power does most of the technical maintenance, while MNL sprays and maintains the plants. The SolTech trackers require slightly more maintenance than pole trackers, and they can go offline due to storms, sheep knocking the sensors, and other natural causes. Background research is being conducted by ENEL to determine whether the tracking system is worth the extra maintenance. At the end of the site’s service life, which is typically 25 years, the developers hope to decommission the system and return the land to agriculture with richer soil than the gravel alternative and unharmed adjacent landscapes. The research from this site will help quantify the benefits that agrivoltaics can bring to both solar development and agriculture industries.

Solar Projects Increase Tax Revenue in North Carolina 

“Proposed large-scale solar facilities continue to draw opposition in North Carolina from critics who argue that swaths of panels are blights on the landscape and threaten farms in a state where agriculture is the leading industry. But those facilities have become a financial boon to local communities, particularly in rural areas with limited sources of tax revenue, a newly released study from the N.C. Sustainable Energy Association found.” – Greensboro 

Dutch Research Studies Agrisolar  

“During a four-year pilot project, Dutch independent research organization TNO, in collaboration with Vattenfall and Aeres University of Applied Sciences (UAS), is developing a sun-tracking algorithm that monitors various factors, such as crop yield, energy yield and the effects of herb strips, weather forecast, energy price and soil condition.” – Vattenfall 

Small Farms in Maine are Good Candidate for Agrivoltaics 

“Maine’s prevalence of small farms with low-lying, hand-harvested crops makes the state a good candidate for blending solar energy and food production on the same land, but farmers may not take the risk without funding for pilot projects. 

Maine may be uniquely positioned for this emerging field, known as agrivoltaics or dual-use solar. Nationally, most successful projects so far have involved extras like solar grazing or pollinator habitat alongside panels at small farms with low-lying, hand-harvested crops — precisely the type of farms that dominate much of Maine’s agricultural sector.” – Energy News 

What are asset managers looking for when they evaluate proposals from solar graziers? What kinds of concerns do asset managers have about grazing that need to be resolved to get to the contract stage?

Keanen Ryan and Lexie Hain from Lightsource bp joined us for a wonderful conversation that answered these questions from the solar operations perspective. Keanen and Lexie also discussed what they’re looking for from graziers in terms of services and experience in order to meet the economic and sustainability standards of Lightsource bp.

The Solar Industry’s Mower of Choice: Sheep 

“The panels blanket nearly 1,500 acres of a solar farm in Deport, a town near the Oklahoma border. Ely Valdez, the boss, makes sure prairie grasses don’t block sunshine from the panels. His sheep do most of the work. Sheep, the surprise workhorse of renewable energy, are generating several million dollars in annual revenue tidying up solar farms nationwide. 

‘It’s changing all of our lives,’ said Mr. Valdez. He expects the flocks he oversees to soon generate several hundred thousand dollars in annual revenue. The number of acres of solar fields employing sheep in the U.S. has grown to tens of thousands from 5,000 in 2018, according to estimates by people in the business. Flock owners charge as much as $500 an acre a year. 

The solar industry auditioned several methods for the job, but requirements weeded out expected contenders. Power mowers, which can’t maneuver easily enough under panels to avoid the risk of damaging equipment, are of limited use. “Sheep truly are the appropriate technology for this,” said Michael Baute, vice president of regenerative energy and carbon removal at solar developer Silicon Ranch Corp., based in Nashville, Tenn.” – The Wall Street Journal 

The “Five C’s” of Agrivoltaics 

“These are among the most important findings of an ongoing agrivoltaics research project called Innovative Solar Practices Integrated with Rural Economies and Ecosystems (InSPIRE). Led by the National Renewable Energy Laboratory (NREL) and funded by the U.S. Department of Energy’s Solar Energy Technologies Office, InSPIRE has just completed its second, three-year phase of research into the synergies between solar energy and agriculture.  

In its first phase, InSPIRE tried to quantify the benefits of agrivoltaics and record some early best practices in the emerging field. The project adopts a big-tent approach to agrivoltaics, welcoming any dual use of solar-occupied land that provides ecological or agricultural benefits. That could mean grazing cattle or sheep, growing crops, cultivating pollinator-friendly native plants, or providing ecosystem services and restoring degraded soil.  

The InSPIRE project found five central elements that lead to agrivoltaics success, summarized as ‘the five C’s’: 

  • Climate, Soil, and Environmental Conditions — The ambient conditions of a location must be appropriate for both solar generation and the desired crops or ground cover.  
  • Configurations, Solar Technologies, and Designs — The choice of solar technology, the site layout, and other infrastructure can affect everything from how much light reaches the solar panels to whether a tractor, if needed, can drive under the panels. “This infrastructure will be in the ground for the next 25 years, so you need to get it right for your planned use. It will determine whether the project succeeds,” said James McCall, an NREL researcher working on InSPIRE.  
  • Crop Selection and Cultivation Methods, Seed and Vegetation Designs, and Management Approaches— Agrivoltaic projects should select crops or ground covers that will thrive under panels in their local climate and that are profitable in local markets.  
  • Compatibility and Flexibility — Agrivoltaics should be designed to accommodate the competing needs of solar owners, solar operators, and farmers or landowners to allow for efficient agricultural activities.  
  • Collaboration and Partnerships — For any project to succeed, communication and understanding between groups is crucial.” –  NREL 
  •  

Illinois University Team Developing Interactive Agrisolar Game  

“A team led by University of Illinois, Urbana-Champaign researchers is developing an educational game it hopes can inspire future farmers to think differently about solar power. The app aims to teach kids the emerging concept of agrivoltaics, in which agricultural production is combined with solar photovoltaics. The game will be backed by science from the growing niche of research looking into how solar panel placement affects the growth of various crops.  

‘Dual-use land is really a great idea, intuitively, so why not build an app that lets kids explore these really interesting ideas while they’re playing a game?’ said H. Chad Lane, associate chair for educational psychology at the University of Illinois, Urbana-Champaign. 

Think Farmville, but instead of gamifying every aspect of running a farm, it will focus on the interaction between crops and solar panels. Researchers are discovering that several plant types can perform better when partially shaded by panels; for others, the reduced production can be offset by extra revenue from selling solar power to the electric grid.” – Energy News Network