This paper highlights the higher annual solar irradiation incident of single-axis N-S trackers installed on sloping terrain, as compared to horizontal ones. Researchers showcase the results of a year-long experiment in which a N-S aligned single-axis tracker prototype was used in Gijón, Spain. The experimental results confirm the trends in the formulas and simulations. Finally, theoretical values for the energy gain for different slopes, at locations over the northern hemisphere between latitudes of 6◦ and 60◦ are provided. These gains can reach values up to 13.5%.
Tag Archive for: Solar
By Allen Puckett, NCAT Technical Writer
The Solar Shepherd provides grazing services in Brookfield, Massachusetts, with 75 sheep that graze a solar array site owned by SWEB Development, a European clean energy firm. This beneficial partnership was born when SWEB reached out to Solar Shepherd for grazing services after seeing their solar-grazing sites on social media. Learn more about the partnership in the AgriSolar Clearinghouse’s video How a Shepherd and Solar Developer are Joining Forces to Grow Sheep, Clean Energy.
Solar Shepherd’s founder and owner Dan Finnegan is a third- generation sheep farmer in eastern Massachusetts. His history working in a corporate environment led him to think more about what was important to him—the land, local farming, and clean energy. While he likes raising sheep, there wasn’t enough acreage for it to be profitable without agrisolar sites.
“It wouldn’t be enough to produce a living for a family,” he said. “This is more than a hobby-farming operation. With solar grazing, we dramatically expand our flock. We work hard to be competitive with landscapers on these sites. The grazing fees mitigate the costs and pay down the investment to take the show on the road (transporting sheep to solar sites). We’re used to farming out the back door, and now we have sites spread hundreds of miles apart. The grazing fees make that cost affordable.”
“I saw a solar array built on a lambing pasture, and a landscaper showed up with a tractor and started mowing up the solar arrays. He was going about 30 mph with a batwing sprayer and was mowing the rows and hosing down the panels around the arrays. I was thinking, they should just put the sheep down there and let them graze,” Dan recalled.
Solar Grazing Site Specifications and Management
The site is in a 15-acre array that produces 5 MW of DC and 3.375 MW of AC, enough to power approximately 1,100 homes. A landowner leases the land to SWEB, and SWEB hires Dan to graze the solar arrays with the sheep. The pricing is relatively the same as traditional mowing and gas-powered landscapers, but grazing sheep comes with many environmental benefits, such as enhanced landscape stabilization that directly benefits the solar companies. This stabilization includes deeper root systems on previously rocky terrain, improved turf health, and significant runoff reduction.
Solar Shepherd practices rotational grazing on their sites, which allows more carbon in the soil and retains more moisture. “We see that impact very rapidly. There are some sites we had that, in just one year, the customer came to us and said, ‘I can’t believe the impact the sheep had on the vegetation sustainability. It was rocky before, and now there are deeper root systems, stabilized soil.’ Erosion is a big concern at the base of the panels. A direct benefit to the solar companies is stabilizing that ground,” Dan added.
There’s also the “Fuzz and Buzz” – a solar seed blend used at the Brookfield site that benefits pollinators and sheep. It’s not as robust of a floral bloom, but the bees and sheep benefit greatly from this blend. A gas-powered mower removes all the vegetation on an array in a single day. The sheep take around a month to “mow” the same array. This allows valuable pollinator habitat to be left for the bees and birds. There’s good seed-to-solar contact, and the imprints from the sheep hooves allow the seeds to be captured in the soil. The sheep help the effectiveness of reseeding a site and some graziers will run the sheep back over the seeds to help stomp them down into the earth.
Solar grazing includes running three main operations: a sheep farm, a trucking company (as you move the animals), and a commercial landscaping business. “It’s more than just opening the gate, throwing the sheep in there, and driving away. There are always some sites that require things outside the lines,” said Dan.
Dan’s partner, border collie Reggie, has been vitally important in effectively managing the sheep on solar sites. In the trucking operation, sheep are loaded in and out of trucks over and over, and that requires collecting them from one site to another to be loaded into the trucks.
Reggie is immensely valuable in this process. She rounds up the sheep quickly, whereas it would take multiple human workers significantly more time. She is vital to effective time management (and cost, if you consider paying multiple workers to round up sheep all the time). Reggie moves the sheep around the array in accordance with rotational grazing practices.
Grant Incentives in Massachusetts
Massachusetts does have a grant program for dual use of solar (Massachusetts SMART Initiative), but it is “written in such a fashion that it can be difficult to be profitable,” said Dan. The grant does not apply to sites that already exist, and it requires panels to be built 10 feet off the ground. Solar Shepherd has not received this grant and has also not yet grazed an array that fits the 10-foot grant requirement.
Livestock production is diminishing in Massachusetts and what’s left is small-scale vegetable farming. Dan speculates that the state is writing laws for solar development incentives with this in mind instead of grazing sheep under solar panels.
“The community loves what we’re up to,” said Dan. “We had about 500 comments (on the recent video featured on CBS) and all of them were loving what we are doing. There are a few political comments. So, grazing sheep on solar might bring some unification from a political perspective.”
He also added that, “At least half the time I show up, there is a family there outside the gate at the fence watching the sheep. People are wanting to bring kids out to the sites to see the sheep. I’d like to do a program where people can come see them. We would love to host a solar event. We’re going to bring some sheep to town off the hill in Brookfield so people can see them and interact with them. I have a dream of bringing a bus load of kids out here to see how bees, sheep, and everything all come together.”
Since the Brookfield location is an ancient hay site where indigenous peoples managed the land when colonists first arrived, not damaging the vegetation or compacting the soil during the solar array installation was very important. This priority to minimize damage to the land could have a positive impact on community support for a solar site, particularly on ancient farmland or similarly valued sites. Communities like to see that a (solar) development company cares about the land and the process of development.
Considerations for New Sheep Graziers
New sheep graziers or those thinking about getting into sheep grazing on solar sites should consider a couple of things throughout the process. Educating themselves on what’s happening on the solar array is very important. “They don’t have to be engineers,” says Dan, “but they should understand what’s happening and what the potential dangers are and keep themselves and animals away from those areas. Stay out of areas where you might think ‘I should have an electrician in there.’ These are areas that contain things like cable trays and equipment pads.”
Don’t move forward with grazing a solar site if you haven’t walked the location and examined it for suitable conditions for your sheep. If construction techniques did not leave a space where you would feel comfortable leaving the sheep, such as poor wire management or dangerous or sharp edges on array components, it may be a good decision to decline grazing in that location. Dan says the sites he turns down are for animal welfare reasons. There might not be enough nutrition on the site, but it is usually wiring management. A good perimeter fence can also make a site more ideal for sheep.
Operating a grazing operation on your own property requires having a plan for food and water delivery, as well as for avoiding predation. A plan should be in place for responding to issues that may arise on the site and with little notice. Solar Shepherd has a 24-7 hotline for such issues.
For fencing, Dan prefers to use electric netting, which provides effective protection from predators. Coyotes prefer to go under the fence rather than over it, and considering such nuances in predator-prevention strategies can help design a fencing system that is most effective for your area and your circumstances. Hiring people who think from the sheep’s perspective is important, says Dan. Fortunately, he has not had any issues with predation to his sheep.
The Future of Solar Shepherd and Solar Grazing
The future of Solar Shepherd is looking bright. It originally took the company approximately one year to get hooves on the ground at a solar site. Now it only takes about a week or two. “I feel great about the solar grazing future and Solar Shepherd. The sales pitches are getting shorter and shorter. The world is becoming aware of this subject. Five years ago, it was, ‘You’re doing what?!’ The last pitch I gave was an hour-long presentation. I got 15 minutes into the meeting, and people said, ‘It’s great; we are ready to sign.’”
OCS Releases Guidance on Community Solar and LIHEAP for Grant Recipients
“The purpose of this grant recipient information is to: 1) confirm that LIHEAP funds can be used for solar energy use through new and existing electric payment mechanisms, such as community solar subscription fees; and 2) provide LIHEAP grant recipients with recommendations to consider when utilizing LIHEAP funds for community solar subscriptions.” – acf.hhs.gov
Benefits of community solar include cost savings, access to clean energy, support for local communities, and flexibility in subscription options.
Solar Grazing Benefits Sheep Herders with Revenue Opportunities
“The US solar industry has been growing rapidly: The country is expected to break solar construction records this year by adding more than 32 gigawatts of capacity, according to a Bloomberg NEF outlook. That’s enough to power more than 25 million homes. At the same time, there are concerns there won’t be enough cropland to feed a growing world population, especially if acreage is covered by buildings, roads or photovoltaic installations instead.
The American Solar Grazing Association, founded in 2018, estimates about 5,000 sheep are currently maintaining US solar sites. ‘The sheep do a better job supporting the biodiversity than a conventional mower,’ said Jay Smith, Director of Asset Management at Standard Solar. In some instances, sheep are better suited to maneuver around solar panels than conventional mowers and help reduce carbon emissions.
The practice [Agrisolar] is giving sheep herders a lifeline, introducing a new revenue stream after a decades-long decline for the US lamb industry. The number of sheep slaughtered in the US has been averaging over 2 million head in recent years, compared to more than 9 million in the early 1970s, according to Department of Agriculture data.” – Bloomberg.com
German Agrisolar Project Uses Solar to Benefit Hop Growth
“Germany’s Agri Energie has commissioned an agrivoltaic project in Hallertau, near Munich, in the German state of Bavaria. The €1.5 million ($1.64 million) project combines solar generation with hop growth.
The company installed the PV system on steel masts, providing protection to hop plants from sunlight and hail, while also reducing evaporation. In addition, the system serves as support for the hop plants.” – PV Magazine
500MW of Community Solar to be Deployed by Community Solar Collective
“Aggreko Energy Transition Solutions (ETS), a business unit of Scottish modular power equipment distributor Aggreko Ltd., announced it would become the capital partner to the Farmers Powering Communities (FPC) platform, a farmland community solar development collective. With preservation and non-profit groups Edelen Renewables, the American Farmland Trust and community solar aggregator Arcadia, the FPC platform is focused on building out 500 MW of community solar projects over the next decade sited on rural farmland.
The farming community solar program will advance projects of 25 to 50 acres to provide green energy to the many residents who don’t have access to rooftop solar or a local clean energy source. These could be low- to middle-income residents who may not be able to afford solar, people who rent and don’t own their roof, or people whose homes are not situated to take advantage of the sun’s energy.” – PV Magazine
Jack’s Solar Garden Hosts Agrivoltaic Bill Signing
Colorado governor Jared Polis recently signed Colorado Senate Bill 092. The bill signing was attended by Senator Chris Hansen; Representative Karen McCormick, DVM; and Colorado Commissioner of Agriculture Kate Greenberg. The signing was hosted at Jack’s Solar Garden, an agrisolar operation in Boulder County, Colorado, and one of the largest agrivoltaic operations in the country.
“In support of the use of agrivoltaics, which is the integration of solar energy generation facilities with agricultural activities, section 2 of the bill authorizes the agricultural drought and climate resilience office to award grants for new or ongoing demonstration or research projects that demonstrate or study the use of agrivoltaics.” – colorado.gov
Oregon State University Shows Benefits of Agrivoltaics
“On a small research farm outside of Wilsonville, Chad Higgins feels like he’s watching the future of farming and energy production unfold. Higgins, a biological and environmental engineering professor at Oregon State University, oversees one of the largest experiments in agrivoltaics in the world.
Using agrivoltaic systems, Higgins has grown tomatoes with bigger yields and dry beans with higher protein content. He’s raised sheep in pastures under solar panels and, though the sheep don’t grow any faster, he’s able to graze more of them per acre because the grass grows more quickly. He’s also found that, because the plants cool the environment around them, the solar panels don’t run as hot and produce energy more efficiently.” - KGW
This article presents a comparison of changes in vine growth and fruit characteristics due to the installation of solar panels in the vineyard. Researchers found that the development of vines and fruits was not significantly different, and that the post-harvest fruit showed no difference in granules, fruit discharge, sugar content, or pericarp color.
Commodity or Specialty: Tracking Pollinator-Friendly SRECS
“The M-RETS platform—the leading renewable environmental attribute tracking system used by Fortune 25 companies, utilities, and regulators—this year will begin tracking an additional environmental attribute associated with grid-scale solar projects: a pollinator-friendly designation. M-RETS already tracks solar renewable energy credits (called S-RECs) and Minnesota is one of a number of states that have created an official standard and system recognizing solar projects that utilize ground cover that provides meaningful benefits to pollinators, song birds, and game birds.
This additional data gives solar energy buyers the opportunity to encourage the development of pollinator-friendly solar and stack additional environmental benefits on their energy purchase.” – M-RETS
This can be thought of as if your company is buying a commodity product or a specialty product. If these options are the same price, would your company prefer to buy a commodity SREC or a boutique SREC?
Spade Develops Agrivoltaic Software
“Solar developer and federal grant recipient Sandbox Solar has released a beta version of its agrivoltaic power plant software modeling tool that aids in the design and optimization of solar panels and the crops underneath.
Sandbox Solar, a solar contractor, has been developing a (software) tool, called Spade. Spade aims to help solar developers determine the best crop types and solar panel layouts for their projects. The tool made it into the fifth and final round of the Department of Energy’s “American Made” solar innovation program.” – PV Magazine
Spade is a stakeholder in the AgriSolar Clearinghouse.
Global Agrivoltaics Market Valued at $9.3 Billion
“Agrivoltaics, the combination of farming practices with energy produced by solar photovoltaics (PV), is forecast to become a $9.3 billion marketplace by 2031, growing at a compound annual growth rate (CAGR) of 10.1% in that timeframe from $3.6 billion a year ago, according to a research note by India-based market research company Allied Analytics.” – PV Magazine
Solar Could Play Important Role in Cannabis Industry
“Solar energy and cannabis cultivation are old bedfellows. PV pioneer John Schaeffer has even credited solar with facilitating the northern California cannabis industry, which in turn supported the nascent PV sector. Now, as the legalization of medical and recreational cannabis gathers pace, solar continues to perform a key role.
Canndescent Senior Director of Compliance Andrew Mochulsky told PV Magazine the Colorado Desert’s unrelenting sunshine and limited cloud cover make solar a no-brainer. ‘We’re in the heart of solar and wind country so it made sense to bring solar online,’ he says. ‘We also think it’s just the right thing to do.’”– PV Magazine
By Anna Adair, NCAT Energy Program Assistant
Located near Richmond, Virginia, the Mechanicsville solar park is one of the state’s first utility-scale solar sites. Covering over 220 acres, the 28-megawatt, single-axis tracking site provides a source of clean power to thousands of homes in the state. More than just a solar site, though, the location is also the home base for hundreds of sheep under the care of Eric Bronson and Sam Perkins at James River Grazing.
James River Grazing started in 2016 when founder Eric Bronson noticed the solar industry beginning to take off in Virginia. A Virginia native, Bronson attended college at Montana State University and worked for several years on large, range-based livestock operations before returning to his home state. He knew he wanted to stay involved in agriculture, but without already owning land, he realized the upfront costs were prohibitive. Compared to raising cattle or growing crops, the lower initial investment needed to successfully farm sheep gave Bronson the chance to farm in a traditional production environment before the company received its first solar grazing contract in 2019.
For solar sites without grazing plans, mowing must be brought in for vegetation management, a difficult task for many solar developers in recent years due to labor shortages. “The grazing came along at the perfect time,” Bronson says. He explains that the Mechanicsville site was being mowed about once a month, but with the integration of livestock, it was reduced to a “clean up” mow in the fall and smaller mows in early spring. Even then, “they’re not mowing one hundred percent of the site,” Bronson explains. Only about a quarter of the site is mowed at these times, significantly lowering the time and labor cost required to control the vegetation.
Operating on the Mechanicsville site didn’t come without its challenges, however. The site hosts between 100 and 300 ewes at a time, depending on the time of year and vegetation growth. While smaller operations will move flocks on and off location seasonally, James River Grazing operates on the site year-round. Not having facilities on-site and the expansive costs to move the sheep off-site is an added layer of difficulty that comes with grazing sheep on utility-scale sites. “Everything has to be portable,” Bronson points out. Nonetheless, James River Grazing’s efforts have been so successful that SunEnergy1, the solar developer for the site, hired Bronson as Director of Livestock for the entire company and has implemented solar grazing on a number of other sites, as well.
With a total of six grazing sites and around 1,500 sheep, Bronson says James River Grazing is looking to continue its success by creating additional partnerships with developers across the region. While being one of the first to embrace solar grazing comes with some advantages, it also means that learning involved a significant amount of trial and error. “That was one of the biggest roadblocks,” Bronson says, referring to the lack of available resources to help guide them in the early days. Their knowledge and experience also put them in an ideal place to help solar developers create construction plans with solar grazing in mind, making it much easier for grazers to care for the sheep on site. James River Grazing is still working out the details for exactly how they plan on moving into the consulting space, but their track record of success will undoubtedly make them a valuable resource for solar developers and new grazers alike.
All photos courtesy of James River Grazing.
NYPA Study Provides Best Practices for Agrivoltaic Systems
“The New York Power Authority (NYPA) announced the release of a new report, Agrivoltaic Leading Practices, that recommends proven and innovative approaches on integrating dual-land use for agriculture and solar energy production. The study determined that a best practice agrivoltaic site ideally involves stakeholder collaboration, community education, policy incentives, site safety practices, and site-individualized crop selection and solar-array design.
Researchers who authored the new report examined how native vegetation, pollinators, low maintenance plants, agricultural crops as well as grazing livestock can coexist on the same parcel of land as a solar energy project.” – The Mountain Eagle
Research Shows Crops and Solar Panels Benefit from Co-Existence
In the threatening trouble of climate change, growing commercial crops on solar farms is a potentially efficient use of agricultural land that can both increase commercial food production and improve solar panel performance and longevity, according to new Cornell research.
“’We now have, for the first time, a physics-based tool to estimate the costs and benefits of co-locating solar panels and commercial agriculture from the perspective of increased power conversion efficiency and solar-panel longevity,’ said lead author Henry Williams, a doctoral student in Cornell Engineering.” – Cornell Chronicle
New Solar Panels Harness Full Light Spectrum and Increase Crop Yields
“According to a new study from the University of California, the blue part of the light spectrum is the most efficient for solar energy production, while the red part is better for plant growth and crop yield. Now, scientists are investigating how harnessing the sun’s complete light spectrum can improve agrivoltaic system’s effectiveness in arid agricultural areas.” – Horti Daily
This article details Louisiana’s current solar decommissioning regulations and makes suggestions for how to improve the state’s approach to decommissioning solar installations.
By Jessica Guarino and Tyler Swanson
The U.S. agrivoltaics industry continues to grow as the desire to pair solar energy production land uses with pollinator habitats, livestock grazing, and crop production increases. However, while the excitement around agrivoltaics in all its forms blazes a new trail for what solar energy land use can look like, eager landowners and developers face a daunting challenge: state laws and local zoning ordinances that have not considered the possibility that agricultural and solar energy production could feasibly be located on the same tract of land.
Through Agrivoltaics in Illinois: A Regulatory and Policy Guide, researchers at the University of Illinois Urbana-Champaign’s Bock Agricultural Law & Policy Program analyze both the state and local laws that will impact agrivoltaic development in Illinois. The guide pays particular attention to county zoning ordinances, each of which define solar energy, and set the requirements necessary to develop it, in their own unique way. Agrivoltaics in Illinois allows landowners and potential solar developers to easily understand the requirements to build solar in their county and may also point developers towards counties where solar energy development faces a lower burden from the zoning board. Further, developers can read through the specific definitions that a county has for solar energy, which may have an impact on the development of agrivoltaics. For example, in many counties, a solar farm is the principal use for the land on which it is located, which could have negative implications for a landowner wishing to practice agrivoltaics and retain the tax benefits associated with land being classified as an agricultural use. Meanwhile, other counties state in their zoning ordinances that a solar installation under a specified acreage is considered a “solar garden” and thus is classified as either an accessory or special use of the land.
Agrivoltaics in Illinois: A Regulatory and Policy Guide, while focused on analyzing the state laws and local zoning ordinances of Illinois, aims to inform all landowners, farmers, and solar energy developers of the types of laws and ordinances that should be taken under consideration when exploring the deployment of an agrivoltaic system. This guide is also a resource for state and local policymakers seeking to understand what impacts existing policies may have on the development of agrivoltaics. For example, the Renewable Energy Facilities Agricultural Impact Mitigation Act is a state law requiring a deconstruction plan for wind and solar energy facilities when they reach their end of life that also provides assurances to the landowners that the land will be restored for agricultural use, which will impact agrivoltaic installations. Additionally, a local official could review the numerous figures and tables in the guide to understand what solar energy requirements are most common, as definitions and requirements for solar energy facilities vary by location.
As the agrivoltaics industry grows, it will become increasingly important to understand the regulatory framework in which it will exist. Many current zoning ordinances consider solar energy a threat to agriculture and regulate the industry accordingly, which may inhibit the ability of eager farmers and solar developers to deploy the practice. Likewise, state governments have the power to influence the development of agrivoltaics through laws such as the Renewable Energy Facilities Agricultural Impact Mitigation Act. With the legal analysis presented in this policy guide, the authors hope that it will be used by stakeholders to foster informed agrivoltaic regulations and deployment of the practice.
Photos: AgriSolar Clearinghouse