Tag Archive for: Pollinators

Timing field management in and around solar fields to optimize conservation opportunities for declining grassland birds

Dr. Amy Johnson, Conservation Biologist and Program Director, Virginia Working Landscapes, Smithsonian’s National Zoo and Conservation Biology Institute

Biodiversity is declining globally at an alarming rate. While multiple ecosystems are at risk, our planet’s terrestrial grasslands are suffering precipitous losses. In North America, less than 1% of native grasslands remain.

As a result, species that rely on grassland habitat are in trouble. A recent study published in Science revealed that grassland birds are declining more than any other group of birds (Rosenberg et al, 2019; Figure 1). These are species that rely on contiguous open spaces, mostly free from trees, for nesting, foraging, and survival.

Figure 1. Grassland birds have declined more than any group of birds in North America. Infographic: Cornell Lab of Ornithology

In the eastern United States, the majority of grassland habitat is under private ownership. Much of these grasslands are working lands, with hay production and grazing being the most common land uses. A growing number of these working lands are also contributing to an expanding network of solar fields, often integrating solar infrastructure into actively farmed or post-agricultural fields. Simultaneously, these eastern grasslands are host to some of North America’s most vulnerable grassland birds, including Eastern meadowlarks, Grasshopper sparrows, and Bobolinks, which have experienced population declines of 75%, 68%, and 65%, respectively, since the 1970s. As such, it is critical that we prioritize research to better understand how these populations are impacted by grassland management. More importantly, in order to be successful in developing effective conservation strategies for these species on working lands, it’s necessary to facilitate a model that considers the needs of both wildlife and people.

In Virginia, a team of conservation scientists is collaborating with community partners and a network of private landowners and producers to conduct research on grassland birds on working lands. Virginia Working Landscapes (VWL) is a program of Smithsonian’s National Zoo and Conservation Biology Institute, and its mission is to promote the conservation of native biodiversity and sustainable land management through scientific research, education, and community engagement. Since 2010, VWL has recruited over 180 properties (totaling over 80,000 acres) that have provided researchers access for the purpose of conducting ecological research on how land management impacts biodiversity. Grasslands included in this research include fallow post-agricultural fields, solar fields, active hayfields, and livestock pastures, restored native grasslands and wildflower meadows. From this, VWL researchers have been able to assess how bird communities respond to different land management practices, including the timing of management, and have been able to apply these findings to best management practices that support grassland bird populations.

Solar is quickly emerging as one of the Virginia’s leading sources of renewable energy, with more arrays being constructed every year. With the majority of these installations occurring in and around agricultural fields, we often think about the impacts that solar may have on grassland bird communities. While there’s been minimal research on this topic (Horváth et al., 2009; DeVault et al., 2014), there are several organizations actively looking into it (see SUNY New Paltz, Virginia Pollinator Smart, Grassland Bird Trust).

One aspect of solar management that hasn’t been discussed in great detail in scientific literature is vegetation management in solar fields specific to grass and shrubland birds. With much of VWL’s research focusing on field management (not to mention the fact that it’s currently peak mowing season here in Virginia!), I wanted to use this as an opportunity to share some insights on how landowners and managers can optimize grassland management for bird communities within solar fields and beyond.

In eastern grasslands specifically, we have identified two distinct communities of birds nesting in grasslands. One we identify as grassland obligates, which include those birds that nest directly on the ground in open grasslands, including species like Eastern meadowlarks, Bobolinks, and Grasshopper sparrows. Others we refer to more commonly as shrubland birds, which often build their nests off the ground in low-lying vegetation amongst the branches of woody shrubs or weaved through the stems of sturdy wildflowers. Examples of these species include Indigo buntings, Field sparrows, and Prairie warblers. Depending on the composition and structure of the vegetation growing in and around your solar fields, it’s possible that both groups of these birds are nesting amongst solar arrays and surrounding habitat. For example, if a solar array is installed in conjunction with a pollinator wildflower mix, it may be likely that shrubland species are nesting nearby. VWL research is demonstrating that wildflower meadows support significantly higher densities of shrubland birds than fallow or agricultural fields. In contrast, arrays surrounded by fescue pasture and/or hay grasses it may be more likely to have higher densities of grassland obligates present, potentially nesting directly on the ground. Therefore, the composition of the vegetation surrounding your solar array could help determine the optimal time for field management based on the nesting phenology of the species most associated with that habitat.

In Virginia, Eastern meadowlarks start nesting as early as April 15, with peak nesting activity occurring in mid- to late May (Figure 2). Bobolinks follow shortly behind with peak nesting activity occurring in early June. Unfortunately, this is also the most popular time for field management, especially if fields are managed for hay and/or grazing, and this can have drastic negative impacts on grassland bird survival. For example, a New York study showed that hay harvests during peak nesting season resulted in 94% mortality of eggs and nestlings of grassland birds (Bollinger et al.,1990). Other species more commonly associated with wildflower meadows, like Blue grosbeaks and Field sparrows will nest into late June/early July. As such, it is important to consider the species using your fields when scheduling field management activities. For this reason, we created a “Field Management Risk Calendar” (Figure 3) to help guide managers on the optimal times to manage fields for the benefit of birds.

Figure 2. An Eastern meadowlark nest hidden amongst hay grasses at the edge of a solar field in Fauquier County, VA. Photos: Amy Johnson
Figure 3. Field management risk calendar for eastern grassland birds in the mid-Atlantic. Infographic: Amy Johnson, Smithsonian’s Virginia Working Landscapes, using data collected in Virginia grasslands.

As the calendar illustrates, delaying field management from mid-June to July 1 can make a significant difference for the survival of nestling grassland birds. Delaying to July 15 or even August 1 is even more impactful, especially for those late-nesting shrubland species. We also recognize, however, that delaying management isn’t always feasible. As such, we are currently collaborating with farmers in Virginia to identify optimal windows for early field management that will still offer opportunities for birds to fledge their young. For example, is it possible to mow early in the season, prior to peak grassland bird nesting, and still provide the necessary vegetation structure for nesting birds in late May and into June? Stay tuned to www.VAWorkingLandscapes.org to hear more as we continue collecting data on this front. In the meantime, I encourage you to refer to our Field Management Guidelines for Grassland Birds to learn more about the species that use our eastern grasslands and how we can adapt our management regimes to optimize their conservation.


References

Bollinger, E.K., P.B. Bollinger, and T.A. Gavin, . 1990. Effects of Hay-Cropping on Eastern Populations of the Bobolink. Wildlife Society Bulletin, 18(2): 142-150.

DeVault, T.L., T.W. Seamans,, J.A. Schmidt., J.L. Belant,, B.F. Blackwell, N. Mooers, L.A. Tyson, and L. Van Pelt. 2014. Bird use of solar photovoltaic installations at US airports: Implications for aviation safety. Landscape and Urban Planning,122: 122-128.

Horvath, G., G. Kriska, P. MalikB. . and Robertson. 2009. Polarized Light Pollution: A New Kind of Ecological Photopollution. Frontiers in Ecology and the Environment, 7: 317-325.

Rosenberg, K.V., A.M. Dokter, P.J. Blancher, J.R. Sauer,, A.C. Smith, P.A. Smith, J.C. Stanton, A. Panjabi, L. Helft, M. Parr, and P. Marra. 2019. Decline of the North American avifauna. Science, 366: 120-124.

Written By: Amanda Gersoff (M.Sc. student), Dr. Seeta Sistla

Natural Resources Management and Environmental Sciences Department, Cal Poly, San Luis Obispo

Our team is studying the ecological aspects of utility-scale solar arrays set on former agricultural land whose understory is maintained by sheep grazing. By gaining a better understanding of the ecological implications associated with panel shading coupled with grazing by sheep, we hope to develop insights into agrivoltaic development that can maximize positive environmental effects while reducing negative externalities. We are currently focusing on two utility-scale solar energy sites located in San Luis Obispo County, California. At these sites, we conduct weekly monitoring to measure surface microclimatic features, soil nutrient cycling processes, and plant community composition.

Collecting soil cores at Topaz Solar Farm. Photo: Amanda Gersoff
Collecting aboveground biomass samples at Topaz Solar Farm. Photo: Amanda Gersoff

We hypothesized that the novel shading caused by the arrays will affect plant and soil dynamics, including decomposition, biomass production, plant moisture content, the timing of plant community events (like flowering duration and time to senescence) and plant nutrient content. Our work has suggested that placing arrays in arid grazing landscapes that are emblematic of the western U.S. can confer synergistic benefits for the plant community and their grazers. For example, our work has found that the plant mass beneath the array rows has high water content, greater nitrogen content (correlated with higher soil plant-available nitrogen), and lower non-digestible fiber content than areas that are grazed but outside the arrays’ direct shading influence. We are currently tracking phenological patterns of greenness and flowering time/duration in the array, to better understand if the traits we are observing correlate with an extension of the growing season for the community with the array’s shading area.

Over the next year, we will continue monitoring to gain a more comprehensive understanding of how exactly spatial heterogeneity created by panel shading influences ecological systems. At both sites, the practice of solar grazing, in which sheep are used to maintain vegetation under solar panels, has been implemented. By combining agricultural and renewable energy production, also known as agrivoltaics, multiple benefits can be realized. Utilizing rotational grazing by sheep is beneficial because it can reduce the costs of mowing and maintenance, support local shepherds, cultivate biodiversity, cycle nutrients into the soil, and decrease the risk of sparks igniting dried grasses. As utility-scale solar energy grows, it is important to look to dual-use solar for increasing efficiency and maximizing environmental benefits.

Rotational grazing by sheep at Goldtree Solar Farm. Photo: Amanda Gersoff
Patterns of phenological differences  vegetation due to shading at Topaz Solar Farm.  Photo: Amanda Gersoff
Owl’s clover (Castilleja exserta): An annual native wildflower common in the rows adjacent to panels at Topaz solar Farm. Photo: Amanda Gersoff

By Lee Walston and Heidi Hartmann, Argonne National Laboratory

Pollinator habitat at a solar facility in Minnesota. Photo: Lee Walston, Argonne National Laboratory.

Many of us have witnessed regional land-use transformations towards renewable energy in the last decade. As the fastest growing electricity generating sector in the U.S., solar energy development has grown more than 20x in the past decade and is projected to be the dominant renewable source of electricity by 2040. The recent DOE Solar Futures Study predicts that over 1 terawatt (TW) of utility-scale solar electricity developments will be required to meet net-zero clean-energy objectives in the U.S. by 2050 (Figure 1). This represents a solar land-use footprint of over 10 million acres across the U.S. – roughly the combined area  of Connecticut, Massachusetts, and Rhode Island.

Figure 1. Source: Solar Futures Study

A fundamental question we all face is how to balance solar energy development with other land uses such as agriculture. Given the current and projected land-use requirements, sustained development of solar energy will depend on finding renewable energy solutions that optimize the combined outputs of energy production, ecosystem services, and other land uses. Dual land-use approaches that co-locate solar energy with other forms of land uses, such as agriculture or habitat restoration, have emerged as promising strategies to improving the landscape compatibility of solar energy. The establishment of native pollinator-friendly vegetation at solar facilities (“solar-pollinator habitat”) is one strategy to improve the multifunctionality of these lands that not only provide renewable energy but also offer several ecosystem service benefits such as: (1) biodiversity conservation; (2) stormwater and erosion control; (3) carbon sequestration; and (4) benefits to nearby agricultural fields.

Understanding the true ecosystem service benefits of solar-pollinator habitat will require field studies in different geographic regions to examine the methods of solar-pollinator habitat establishment and link these processes with measured ecosystem service outputs. Given the time required to conduct these direct field studies, most discussions of solar-pollinator habitat thus far have centered on qualitative ecosystem outcomes. Fortunately, there are ways to quantitatively understand some of these potential outcomes. Native habitat restoration has been a focus of scientific research for many years, and we can use these studies to understand the regional methods for solar pollinator habitat establishment (e.g., types of seed mixes, vegetation management) and relate these habitat restoration activities with quantifiable ecosystem responses. For example, there are decades of research on the restoration of the prairie grassland systems in the Midwest and Great Plains – regions that have seen losses of over 90% of their native grasslands due to agricultural expansion.

Because many solar facilities in the Midwest are sited on former agricultural fields, research on ecological restoration of former agricultural fields could be very useful in understanding the establishment and performance of solar-pollinator habitat in the same region. We can look to these studies as surrogate study systems for solar-pollinator habitat and utilize the data from these studies to make inferences on the ecosystem outcomes of solar-pollinator habitat. Along with a team of research partners, we recently took this approach to quantify the potential ecosystem services of solar-pollinator habitat in the Midwest. Our goal was to understand how solar energy developments co-located with pollinator-friendly native vegetation may improve ecosystem services compared to other traditional land uses. We began by reviewing the literature to collect a range of data on vegetation associated with three different land uses: agriculture, solar-turfgrass, and solar-pollinator habitat. The data for each land use included information on vegetation types, root depths, carbon storage potential, and evapotranspiration, to name a few.  

We then developed ecosystem service models for each land use scenario. The land uses corresponded to the following scenarios (Figure 2):

1. Agriculture scenario (baseline “pre-solar” land use);

2. Solar-turfgrass (“business as usual” solar-turfgrass land use) and

3. Solar-pollinator habitat (grassland restoration at solar sites).

We mapped and delineated 30 solar sites in the Midwest and used the InVEST modeling tool to model the following four ecosystem services across all sites and land-use scenarios:

Figure 2. Illustration of land use scenarios at each solar site. Source: Walston et al., 2021.

Our results, published in the journal Ecosystem Services, found that, compared to traditional agricultural land uses, solar facilities with sitewide co‑located, pollinator‑friendly vegetation produced a three-fold increase in pollinator habitat quality and a 65% increase in carbon storage potential. The models also showed that solar-pollinator habitat increased the site’s potential to control sedimentation and runoff by more than 95% and 19%, respectively (Figure 3). This study suggests that in regions where native grasslands have been lost to farming and other activities native grassland restoration at solar energy facilities could represent a win‑win for energy and the environment.

What do these results mean? We hope these results can help industry, communities, regulators, and policymakers better understand the potential ecosystem benefits of solar-pollinator habitat. These findings may be used to build cooperative relationships between the solar industry and surrounding communities to better integrate solar energy into agricultural landscapes. While our study provides a quantitative basis for understanding these potential ecosystem benefits, additional work is needed to validate model results and collect the primary data that would support economic evaluations to inform solar-native grassland business decisions for the solar industry and quantify the economic benefits of services provided to nearby farmers, landowners, and other stakeholders.

Figure 3. Average ecosystem service values for the thirty Midwest solar facilities modeled with InVEST: (A) pollinator supply; (B) carbon storage; (C) sediment export; and (D) water retention. Source: Walston et al. 2021.

By Briana Kerber, Fresh Energy

As we continue to deploy clean energy across the United States, more attention is being paid to how best to develop clean energy projects at the pace and scale that the climate crisis requires, while also ensuring that we are taking care of the sites and communities that host those projects. That’s where a national project from the National Renewable Energy Laboratory (NREL), Great Plains Institute (GPI), Fresh Energy, and the University of Minnesota comes in. Funded by the U.S. Department of Energy’s (DOE) Solar Energy Technology office, the Photovoltaic Stormwater Management Research and Testing (PV-SMaRT) project is using five existing ground-mounted photovoltaic (PV) solar sites across the United States to study stormwater infiltration and runoff at solar farms.

Jake Galzki, researcher at the University of Minnesota, measures water infiltration and runoff at Connexus Energy’s Ramsey Renewable Station site. Photo: Aaron Hanson

Together, the five sites represent a range of slopes, soil types, geographical locations, and PV configurations that will help solar developers and owners, utility companies, communities, and clean energy and climate advocates better understand how best to support solar projects and the host communities in which they are built, in particular lowering the costs of clean energy development while ensuring protection of the host community’s surface and ground waters.

On the banks of the Mississippi

With black-eyed Susan flowers dotting its expanse, the Minnesota site stands out among the five sites in the project. Situated on 18 acres of county-owned land near the Mississippi River in Ramsey, Minnesota, 30 miles northwest of the Minneapolis-St. Paul metro area, Connexus Energy’s Ramsey Renewable Station is flanked by an RV service center to its east, a highway to the north, and a specialty vegetable farm that grows pumpkins and peppers on the project’s west and south sides. Thanks to a partnership with the team at Bare Honey, a Minnesota-based honey producer, the site hosts beehives, too. The 3.4 megawatts of solar panels face south, in a two-in-portrait configuration on a fixed-mount racking system. Throughout the array, the panels are 24-36″ above the ground at the lowest edge.

Blanketed with sandy soil, the Connexus site was seeded with a pollinator-friendly vegetation mix throughout the array and open areas. And the pollinator-friendly aspect was the lynch pin in garnering community support. Pollinator experts and ecologists testified this wouldn’t be just any solar development—it would be a seasonally blooming, low-growing meadow, giving work opportunities to local seeders and apiaries as well as providing ecological benefits to the nearby crops surrounding watershed. Between the sandy soil and the ground cover, when it rains—or even pours—any excess water is channeled into the ground. And that has significant meaning for researchers, solar developers, utilities, and clean energy advocates alike.  

The Minnesota PV-SMaRT site, developed by Engie Distributed Solar for Minnesota’s Connexus Energy. Photo:Aaron Hanson


Designing solar sites for extreme weather

Part of the process of planning out or conducting analyses on clean energy developments like solar farms is to test how well the site will hold up against an extreme weather event, like a flood. Engineers and researchers utilized three different design storms, essentially model storms of various magnitudes, to test Ramsey Renewable Station’s response and evaluate rainfall and soil moisture as well as determine how fast excess water would soak into the ground.

Through these models, the PV-SMaRT research team discovered that, against three design storms—two-year frequency storm, 10-year frequency storm, and 100-year frequency storm, the most intense of the three—all stormwater was channeled into the soil by the deep-rooted vegetation. Using both an InVEST modeling framework and a 2D Hydrus water model, University of Minnesota (UMN) researchers involved in the PV-SMaRT project, including Aaron Hanson and Jake Galzki, led by UMN professor Dr. David Mulla, have been able to keep tabs on the site, monitoring data from moisture sensors and comparing numbers from the site to those of other PV-SMaRT locations.

In fact, the team found that if they wanted to observe a runoff response, they had to actually reverse engineer the site to provoke one. For example, if the team conducted a model of the site in which vegetation suffered due to heavily compacted soil, then they could observe a runoff response. But, in virtually every other scenario, the combination of the diverse, deep-rooted pollinator-friendly vegetation and sandy soil ensures that all excess water soaks directly into the ground. In the research team’s eyes, that made the Connexus Energy Ramsey site a prototype for the rest of the PV-SMaRT project.

Benefits for the site and the study

And Brian believes that those involved in stormwater permitting at solar sites can learn something from the Ramsey example. “As a result of this study, stormwater permitting at sites such as this can be predictable and transparent to both the city or county and the developer,” he says, “reducing soft costs for solar developers while ensuring good water quality outcomes for regulators and habitat co-benefits for local communities.”

Vice President of Renewable Energy at GPI, Brian Ross notes that the site is important because it serves as a sort of bookend for the project: “It is a site that requires only ground cover green infrastructure in almost any circumstances. Comparing this site to our other project sites is incredibly useful. The characteristics at play at Connexus Energy’s Ramsey solar site point toward the potential capacity of a solar farm to mitigate not only the site but also contribute to broader watershed management.”

At Connexus Energy, Rob Davis, communications lead, points out that there was an overwhelmingly positive community response to the pollinator-friendly aspects of the project. “That’s why Connexus requires pollinator-friendly ground cover for all our solar sites, and it was especially important for this project due to the location near the Mississippi River and a specialty crop grower. The site’s soil and ground cover combine to easily handle heavy rainfall events,” he says.

Jake Galzki, researcher at the University of Minnesota, inspects soil and water monitoring equipment at Connexus Energy’s Ramsey Renewable Station site. Photo:Aaron Hanson

Rob notes that when the project was built, it did not have the advantage of accurate hydrological models for PV solar projects, which resulted in a requirement for grading that included carving a two-foot bump diagonally through the project. Thanks to insights from the PV-SMaRT study, Rob is confident that policy changes can be made to avoid grading in the future, as it unnecessarily disturbs the soil and creates an uneven surface for vehicles managing a site. In its place, Rob points to the high-performance vegetation, as it requires less grading and fewer stormwater containment basins and is therefore a much better use of limited maintenance funds.

Insights yet to come

Data and observations from the Connexus Ramsey site serve as a benchmark as the PV-SMaRT research team continues to gather insight about the four other project sites across the country. Overall, the findings from the Ramsey site further validate the project’s recommended best practices in exemplifying how we can lower the soft costs of clean energy development and of ongoing maintenance while protecting the host community’s surface and ground waters, create needed habitat, sequester carbon in the soil, and help craft a truly sustainable clean energy future that will benefit everyone for generations to come. Read more about ongoing validation of this foundational research via Great Plains Institute.

A version of this article was originally published via Fresh Energy. Read it here.

USDA is soliciting nominations for members to serve on its newly formed USDA National Pollinator Subcommittee. The subcommittee will be part of the National Agricultural Research, Extension, Education, and Economics (NAREEE) Advisory Board, which provides feedback to the Secretary of Agriculture, USDA’s science agencies, and university collaborators on food and agricultural research, education, extension, and economics priorities and policies. USDA is seeking nominations for subcommittee members until May 31, 2022, from individuals with diverse expertise in pollinator health. USDA expects to appoint seven new Pollinator Subcommittee members for one- to three-year terms beginning in July 2022.

Guest blog post by Monarch Joint Venture

Up to 99% of native northern tallgrass prairie in the U.S. has disappeared since European settlement (Samson and Knopf, 1994). This loss of habitat is devastating for pollinators including the iconic monarch butterfly, which depends on native milkweed species and a variety of nectar plants to survive. Given this stark situation, one of the most impactful conservation actions any of us can take is to plant and maintain native habitat, whether it’s a backyard pocket prairie or a large-scale restoration. Many sectors, from agriculture to managed public lands to transportation rights-of-way, are exploring the benefits of pollinator-friendly habitat. Renewable energy is no different; in fact this sector has been a pioneer in the field…the solar field, that is.

In recent years, pollinator-friendly habitat creation on photovoltaic (PV) solar sites has gained momentum across the country, with Minnesota among the earliest adopters. In 2016, Minnesota became the first state to incentivize pollinator-friendly ground cover on its solar energy sites through Minnesota Statute 216B.1642. This development came on the heels of the 2015 National Strategy to Promote the Health of Honey Bees and other Pollinators, which catalyzed new conservation strategies across the nation.

“Minnesotans value conservation and pollinator health, so it’s natural that Minnesota is a leader in this area. You also see this in the preferences expressed by leading electric utilities like Connexus and Xcel,” says Rob Davis of Connexus Energy, which participated in the short documentary, “Pollinators, Prairie, and Power,” last year. “Whether a co-op like Connexus or a private or investor-owned company, energy buyers of all kinds can use the standards published by the state’s leading pollinator experts to express preferences in their renewable energy purchasing. It’s never been easier for energy buyers to ask for high-quality habitat as a ground cover for PV solar—there are numerous developers competing to win these projects.” 

This increasing interest is timely: Between 300,000 and 400,000 acres or land in the U.S. are currently being used for ground-mounted PV solar, and studies predict that 3-5 million acres of large-scale solar will be added to the landscape by 2035. According to the Solar Energy Industries Association, solar accounted for 54% of all new electricity-generating capacity added in the U.S. in the first three quarters of 2021, with projections for growth holding steady. Now is definitely the time to quantify the benefits of habitat-friendly landscaping among solar arrays, and that’s where the Monarch Joint Venture comes in.

During the summer of 2021, MJV partnered with Minnesota-based nonprofit Fresh Energy to monitor pollinator-friendly habitat on Minnesota solar developments. Founded in 1990, Fresh Energy works to shape and drive policy solutions to achieve equitable carbon-neutral economies, including habitat-friendly solar.

“We wanted to begin quantifying the impacts of pollinator-friendly solar on Minnesota’s pollinator populations,” says Michael Noble, executive director at Fresh Energy. “Habitat plantings under solar arrays can add a small amount to the cost of a solar development project, but this study shows that it’s an investment well worth making for the benefit of Minnesota’s critical pollinators.”

Using data collected during the study, MJV and Fresh Energy have released the Monitoring Pollinators on Minnesota Solar Installations report to demonstrate the potential benefits of using pollinator-friendly ground cover with solar arrays in Minnesota—as well as areas that need further research. Fresh Energy will be hosting a deeper dive into the report’s findings in a webinar on May 18th. Learn more and register here.

For the study, MJV National Monitoring Coordinator Laura Lukens surveyed four PV solar installations during June, July, and August 2021 to measure the abundance and species composition of milkweeds and flowering plants, as well as use by monarch butterflies and other pollinators. Survey and sampling protocols were designed in consultation with Argonne National Laboratory, which, in partnership with NREL’s InSPIRE study, has published research on use of native plants as solar array ground cover. The sites were located in Anoka and Ramsey counties, ranged in size from 18-68 acres, and were seeded with a native pollinator mix in either 2017 or 2018. A completed copy of Minnesota’s Habitat Friendly Solar Scorecard was available for each site. This monitoring provides essential information for solar site operators and other stakeholders to create long-term management plans to keep native ground cover thriving, and contributes to a growing amount of evidence that habitat-friendly solar sites can provide significant benefits to pollinators.

“Monitoring this habitat is important for many reasons,” says Laura. “Field surveys allow us to investigate potential impacts of solar array canopies on plant and pollinator communities and provide empirical evidence to back up what we suspect as being benefits of habitat in these spaces. With solar projected to grow by millions of acres in the next 15 years, this presents an exciting opportunity for the renewable energy sector to contribute to national pollinator and habitat conservation goals.” With more and more energy companies adopting habitat-friendly solar, this is good news indeed for pollinator conservation.

While surveying, Laura utilized a variety of monitoring protocols, including the Integrated Monarch Monitoring Program (IMMP), the MJV-administered national program that collects milkweed, flowering plant, and monarch use data from a variety of land-cover types and regions. Utilized by researchers and land managers, the IMMP also is a robust community science program designed for public participation. IMMP community and professional scientists contribute important data that are then utilized by monarch and pollinator conservationists and policymakers. 

In a nutshell, over the course of the monitoring project, Laura observed a high number of flowering plant species and an abundance of bees, butterflies, moths, flies, and wasps flourishing within and adjacent to the solar arrays. “These results indicate that pollinators utilized habitat regardless of solar panel presence,” Laura shares. “And this suggests that solar installations in Minnesota can indeed provide quality breeding and foraging habitat for monarchs and other pollinators.” 

At the same time, the project was limited in scope, and represents preliminary findings. Continued long-term data collection is critical for monitoring the status and trends of pollinator populations, investigating other co-benefits of solar habitat, and to ensure that pollinator-friendly practices achieve and maintain desired outcomes. Management of these sites will also be key to ensuring that habitat quality does not degrade through time.

Other researchers are studying additional co-benefits of habitat-friendly solar. For instance, PV-SMaRT, a collaborative project by the Department of Energy’s National Renewable Energy Laboratory, Great Plains Institute, Fresh Energy, and the University of Minnesota, is studying stormwater infiltration and runoff at PV solar sites across the U.S. Additionally, the U.S. Department of Energy (DOE) Solar Energy Technology Office is funding a four-year study investigating the impacts of co-location of pollinator plantings at large-scale solar installations (>10 MW), led by the University of Illinois, Chicago, in partnership with Argonne National Laboratory, the National Renewable Energy Laboratory, University of Illinois Urbana-Champaign, and Cardno (now Stantec). One of this project’s goals is to create tangible guidance and tools for industry use (e.g. pollinator planting implementation manual, solar site seed selection tool, pollinator solar field assessment tool, and cost-benefit calculator).

In addition to benefits for pollinators and other organisms, native ground cover on PV solar sites can also promote soil health, improve water quality, reduce runoff, and may even boost electrical output, especially on warmer days, by keeping the microclimate near the ground cooler. 

“Overall, habitat on solar arrays by itself will not solve the biodiversity crisis or arrest the decline in the monarch or other species,” Rob Davis adds. “However, solar with pollinator-friendly ground cover is setting a beneficial example for other developments to follow. All these things together with additional actions to conserve previously undisturbed lands and set more acres aside dedicated to conservation, through the USDA’s CRP and other programs, will benefit biodiversity and overall human health.”

By Rob Davis, Connexus Energy

Seven years after designing our first solar array, more than 20 million deep-rooted and pollinator-friendly plants across more than 150 acres are helping us control costs while maximizing local benefits for our community, resulting in national recognition and hometown goodwill — but it almost didn’t happen. Now, our standard practice is to require pollinator-friendly ground cover across all of the large-scale solar arrays that feed into our grid.

Connexus Energy is Minnesota’s largest electric cooperative and one of the 15 largest retail electric cooperatives nationwide, serving more than 320,000 people (141,000 meters) in parts of eight Minnesota counties. By embracing innovations including grid-scale battery storage, more than $25 million of local solar generation, customer-centric demand response programs, and automated metering infrastructure, Connexus has kept retail rates to our members flat for five consecutive years, while progressing with greening the grid.

Our first solar array—built in 2014 immediately adjacent to our headquarters—was initially designed with gravel, but a change set us on a different course. Working with one of our co-op members, Prairie Restorations of Princeton, Minnesota, a low-growing meadow seed mix was designed and implemented. Making productive use of the land under and around a ground-mounted solar array fits with one of the seven cooperative principles — Concern for Community. After a year or two of growing in, the site’s beneficial plants were crowding out weed species, reducing mowing costs, and making a positive impression with the community.

Connexus Energy’s HQ Solar Array Built in 2014. Photo: Rob Davis

Having now partnered in the development of four additional grid-scale solar projects—two of which include 15 MW of battery storage—Connexus’ decision to proactively ask for productive use of the land under and around the panels is continuing to pay dividends:

  • Last fall one of Minnesota’s award-winning filmmakers teamed up with Prairie Restorations on a short documentary, Pollinators, Prairie, and Power, which included Connexus Energy CEO Greg Ridderbusch. Click HERE to watch it.
  • The Associated Press recognized Connexus Energy’s leadership in solar land-use practices in a major news story that generated more than 150 million media impressions nationwide. Connexus was the only electric utility included in the expansive story that also included interviews with scientists from the National Renewable Energy Laboratory. The story, “Bees, Sheep, Crops: Solar Developers Tout Multiple Benefits,” appeared in more than 240 media outlets in 41 states and territories.

Earlier this year, the U.S. Department of Energy Secretary Granholm highlighted Connexus Energy, sharing an extraordinary Minnesota Public Radio story about co-op innovation and use of local solar to keep rates flat. 

  • Research on one of Connexus’ solar projects by NREL, the University of Minnesota, and nonprofit partners is quantifying substantial stormwater benefits of deep-rooted ground cover. The PV-SMaRT project is monitoring and collecting water-quality data from five U.S. solar sites with different land and climate conditions. “The end goal is to develop research-driven tools and best practices that can be used by permitting authorities and PV developers to make more informed decisions on stormwater management measures that are tailored to the true impacts of a PV array on the environment,” says Jennifer Daw, principal investigator for the PV-SMaRT project and Group Manager for Strategy, Policy & Implementation at NREL.

This publication provides a pictorial guide to several of the most beneficial hedgerow plant species used in farmscaping for native pollinators and insect predators and parasites in California.

This is a summary of research that tested the efficacy of prairie strip practice to improve honey beekeeping while maintaining a community of wild pollinators compared to farms without prairie strips.

Agrisolar is a rapidly expanding sector with incredible potential. It brings together two major sectors of our society and economy: agriculture and energy. The goal of this guide is to draw on past experiences, to take stock of “what works” and “what doesn’t,” in order to advise local and international actors on successfully developing Agrisolar. This first edition of the SolarPower Europe Agrisolar Best Practices Guidelines takes a step in joining forces with agricultural stakeholders to better understand how the solar and agricultural sector can work more closely together, enhancing synergies to advance the energy and climate transition. Every Agrisolar project is unique as it must be adapted to the local agronomical, environmental, and socioeconomic conditions of the project site, and adapted to the needs of farmers and other relevant stakeholders. The most important element to ensure that Agrisolar projects perform effectively as agricultural and photovoltaic projects is to begin by clearly defining a Sustainable Agriculture Concept. Defining a Sustainable Agriculture Concept means assessing how to improve the sustainability of the agricultural practices carried out on site, assessing whether the project can provide local ecosystem services, assessing how it can be best integrated within the local social and economic setting, all while generating clean electricity. Following best practices throughout all 19 areas identified in these guidelines will ensure Agrisolar projects deliver tangible benefits, as planned in the Sustainable Agriculture Concept.