Solar grazing is on the rise in the United States with dozens of new operations springing up across the country. However, with all of this growth in mind, an important question remains: if a grazier wants to enter the solar grazing market, how much will it cost, and how much revenue can they generate? Budget templates exist that can provide a grazier with guidelines, but hard data on grazier costs and revenues is more difficult to come by.

Researchers at the University of Illinois Urbana-Champaign’s Bock Agricultural Law & Policy Program set out to answer this question as a project through the National Renewable Energy Laboratory’s ASTRO InSPIRE Seed Grant Program. Undergraduate students Tyler Swanson and Quin Karhoff, supported by Post-Doctoral Researcher Jessica Guarino and Professor A. Bryan Endres, conducted a survey of American solar grazing practitioners to gather data on common capital and labor investments, as well as operation sizes and revenue streams. The researchers hope that the findings of the survey will help graziers interested in entering the solar grazing market better understand what costs and revenues they can expect and contribute to more accurate budget tools for potential solar graziers. The results of the survey are included in their fact sheet The Economics of Solar Grazing.

This study was conducted to compare lamb growth and pasture production from solar pastures in agrivoltaic systems and traditional open pastures over two years in Oregon. This study showed that successful agrivoltaic systems are possible where lamb and energy production can be produced simultaneously from the same land. Comparable spring lamb growth and liveweight production per hectare from open and solar pastures demonstrate that agrivoltaic systems would not decrease the production value and potential of the land. In investigating the land use equivalence ratio, agrivoltaics enables increasing the land productivity up to 1.81 for pasture production and 2.04 for spring lamb production through combining sheep grazing and solar energy production on the same land as compared to single use systems. In addition to the increased land productivity and improved animal welfare, the results from this study support the benefits of agrivoltaics as a sustainable agricultural system. Overall, lower pasture yields under in fully shaded areas under the solar panels were the main cause of inferior pasture production in agrivoltaic sites. When designing pasture mixtures for agrivoltaic systems, a selection of pasture species that are not only tolerant to shade but also persistent under heavy traffic should be considered. Limiting the daily grazing time (e.g., on-off grazing: 3 h-grazing/d only) or rotational grazing pastures at low grazing intensities may be viable options for sustainable grazing of seasonally wet soils under solar panels.

In this study, researchers outline practical considerations for grazing land adaptations with an eye towards our changing climate. Flexibility and learning under uncertainty are the overall themes, with an emphasis on collaborative research between researchers and land managers.

In this study, researchers examined the impacts of animal agrivoltaics on the thermal comfort and wellbeing experienced by dairy heifers, and the potential benefit of offsetting enteric methane emissions. The shade provided by the solar panels efficiently relieved the heat load on the cattle, cooled off their body surface and skin temperatures, and decreased the costs of thermoregulation. Researchers concluded that 4.1 m2 of solar panels would be necessary to offset the methane emitted by the cows.

This life cycle assessment study investigates the environmental performance of sheep-based agrivoltaic systems and concludes that agrivoltaic systems are superior to conventional ground-mounted PV systems because they have dual purposes and reduce the environmental impacts associated with producing food and electricity.

The main goal of this research was to find optimal management strategies for sheep flocks kept on solar arrays. Researchers studied flock health and productivity parameters, as well as forage production and quality in a multi-year colloborative trial on a 54-acre solar array adjacent to Cornell University campus. The study concluded that stocking densities of 12, 16, and 20 sheep per acre were successful in maintaining the vegetation within solar arrays, while grazing densities between 12 and 16 sheep per acre may be more complementary for flock health and condition.

Emma W. Kampherbeek, Laura E. Webb, Beth J. Reynolds, Seeta A. Sistla,
Marc R. Horney, Raimon Ripoll-Bosch, Jason P. Dubowsky, Zachary D. McFarlane

A study led by Emma Kampherbeek (Wageningen University & Research, the Netherlands)  highlights multiple benefits of coupling solar energy production to sheep grazing in rangeland systems. This project investigated how sheep use solar arrays as a forage site and the impacts of solar array presence on forage quality in a California Central Coast site with a Mediterranean climate. Sheep with access to solar panels graze more than when they are on nearby native rangeland without an array.  This increased foraging behavior is likely driven by a combination of the protection that the array provides the sheep from weather conditions, which increases grazing time, as well as increased protein content and digestibility of forage with the array footprint.

This resource discusses components of managed grazing such as: historical herbivore effects on grasslands, limitations of past research, managing grazing to restore ecological function and management tactics used to achieve sustainable finance goals. All of these considerations relate to aspects of developing AgriSolar operations that include grazing and a need for grazing strategies. Scientists partnering with farmers and ranchers around the world who have improved their land resource base and excel financially have documented how such land managers produce sound environmental, social, and economic outcomes. Many of these producers have used Adaptive Multi-Paddock (AMP) grazing management as a highly effective approach for managing their grazing lands sustainably.

This is a two-page checklist covering the important issues for both shepherds and solar site managers to consider when managing vegetation under solar panels by grazing sheep. The checklist for solar-site operators includes grazing vs. mowing expectations, insurance updates, and arrangement considerations for the shepherd. The checklist for the shepherd includes determination of fencing plans, maintenance vehicle considerations, signage for property containing grazing animals, and vegetation management plans, among others.

Photovoltaic panels can provide artificial shades to protect livestock against intense solar radiation while serving as a clean energy source. This study determined livestock shade preference between photovoltaic panels and the classical 80% blockage cloth material, and quantified the reduction in radiant heat load provided by these shade structures. The results show that the cattle spent more than 70% of their time in the shade during conditions of the study. These results can be useful in determining best practices on agrisolar operations that include livestock.