The combined use of solar photovoltaics and agriculture may provide farmers with an alternative source of income and reduce heat stress in dairy cows. The objective of this study was to determine the effects on grazing cattle under shade from a solar photovoltaic system. The study was conducted at the University of Minnesota West Central Research and Outreach Center in Morris, Minnesota on a grazing dairy. Twenty-four crossbred cows were randomly assigned to 2 treatment groups (shade or no shade) from June to September in 2019. The replicated (n = 4) treatment groups of 6 cows each were provided shade from a 30-kW photovoltaic system. Two groups of cows had access to shade in paddocks, and 2 groups of cows had no shade in paddocks. All cows were located in the same pasture during summer. Behavior observations and milk production were evaluated for cows during 4 periods of summer. Boluses and an eartag sensor monitored internal body temperature, activity, and rumination on all cows, respectively. Independent variables were the fixed effects of breed, treatment group, coat color, period, and parity, and random effects were replicate group, date, and cow. No differences in fly prevalence, milk production, fat and protein production, or drinking bouts were observed between the treatment groups. Shade cows had more ear flicks (11.4 ear flicks/30 s) than no-shade cows (8.6 ear flicks/30 s) and had dirtier bellies and lower legs (2.2 and 3.2, respectively) than no-shade cows (1.9 and 2.9, respectively). During afternoon hours, shade cows had lower respiration rates (66.4 breaths/min) than no-shade cows (78.3 breaths/min). From 1200 to 1800 h and 1800 to 0000 h, shade cows had lower body temperature (39.0 and 39.2°C, respectively) than no-shade cows (39.3 and 39.4°C, respectively). Furthermore, between milking times (0800 and 1600 h), the shade cows had lower body temperature (38.9°C) than no-shade cows (39.1°C). Agrivoltaics incorporated into pasture dairy systems may reduce the intensity of heats stress in dairy cows and increase well-being of cows and the efficiency of land use.
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The objectives of the thesis were to investigate electrical energy use on dairy farms located in west central Minnesota and to evaluate the effects of shade use by cattle from solar photovoltaic systems. As the push for sustainable food production from consumers continues to grow, food industries and processors are looking for ways they can be more marketable to consumers. Not only do food industries investigate sustainable practices within their own systems, they also push their suppliers to explore ways to lower their farms’ carbon footprints. Measurements of baseline fossil fuel consumption within dairy production systems are scarce. Therefore, there is a need to discern where and how fossil fuel-derived energy is being used within dairy production systems. Baseline energy use data collection is the first step in addressing the demand for a reduced carbon footprint within dairy production systems. Energy use on five Midwest dairy farms was evaluated from July 2018 to December 2019. Through in-depth monitoring of electricity-consuming processes, it was found that electricity use can differ quite drastically in different types of milking systems and farms. Electricity on an annual basis per cow ranged from 400 kWh/cow in a low-input and grazing farm to 1,145 kWh/cow in an automated milking farm. To reduce electrical energy consumption as well as reduce the effects of heat stress in pastured dairy cows, producers may investigate using an agrivoltaic system. Biological effects of internal body temperature, milk production, and respiration rates and behavioral effects of activity, rumination, fly avoidance behaviors, and standing and lying time of the solar shade were evaluated. Treatment groups were shade or no shade of cattle on pasture. The results of this agrivoltaic system suggested that grazing cattle that have access to shade had lower respiration rates and lower body temperatures compared to cattle that do not have access to shade. Electricity used in dairy farms was examined to help producers find areas in their farms that have the potential for reduced energy consumption. Furthermore, the use of an agrivoltaic system on a pasture-based dairy was studied for its shading effects on the health and behavior of dairy cows.
As an answer to the increasing demand for photovoltaics as a key element in the energy transition strategy of many countries—which entails land use issues, as well as concerns regarding landscape transformation, biodiversity, ecosystems and human well-being—new approaches and market segments have emerged that consider integrated perspectives. Among these, agrivoltaics is emerging as very promising for allowing benefits in the food–energy (and water) nexus. Demonstrative projects are developing worldwide, and experience with varied design solutions suitable for the scale up to commercial scale is being gathered based primarily on efficiency considerations; nevertheless, it is unquestionable that with the increase in the size, from the demonstration to the commercial scale, attention has to be paid to ecological impacts associated to specific design choices, and namely to those related to landscape transformation issues. This study reviews and analyzes the technological and spatial design options that have become available to date implementing a rigorous, comprehensive analysis based on the most updated knowledge in the field, and proposes a thorough methodology based on design and performance parameters that enable us to define the main attributes of the system from a trans-disciplinary perspective. The energy and engineering design optimization, the development of new technologies and the correct selection of plant species adapted to the PV system are the areas where the current research is actively focusing in APV systems. Along with the continuous research progress, the success of several international experiences through pilot projects which implement new design solutions and use different PV technologies has triggered APV, and it has been met with great acceptance from the industry and interest from governments. It is in fact a significant potential contribution to meet climate challenges touching on food, energy, agriculture and rural policies. Moreover, it is understood—i.e., by energy developers—as a possible driver for the implementation of large-scale PV installations and building integrated agriculture, which without the APV function, would not be successful in the authorization process due to land use concerns. A sharp increase is expected in terms of number of installations and capacity in the near future. Along this trend, new concerns regarding landscape and urban transformation issues are emerging as the implementation of APV might be mainly focused on the efficiency of the PV system (more profitable than agriculture), with insufficient attention on the correct synergy between energy and food production. The study of ecosystem service trade-offs in the spatial planning and design for energy transition, to identify potential synergies and minimize trade-offs between renewable energy and other ecosystem services, has been already acknowledged as a key issue for avoiding conflicts between global and local perspectives. The development of new innovative systems (PV system technology) and components (photovoltaic devices technology) can enhance the energy performance of selected design options for APV greenhouse typology.
This study aims to review existing literature about agrivoltaics and use experimentation to explore if the advantages they provide are great enough to justify their introduction into Australian agriculture. A key parameter for this study is land productivity that is measured using “land equivalent ratio” (LER) which is a combination of crop yield (measured in kilograms) and energy production (measured in watt-hours).
This case study shows that, in a mature vineyard, with a typical panel steering policy conservative on crop yield, growers could save 13% of water compared to an open-field reference. Experimental data pertaining to apple trees, grapevines, tomatoes, and maize were collected in this study.
The rapid increase of photovoltaic installations highlights the potential of agrivoltaic systems. These dual-land use systems mitigate land use conflicts for places with limited open space and moreover, show the potential as an added value in crop- and livestock cultivation. The many different names and interacting possibilities between agriculture and PV make it difficult and confusing for stakeholders to compare and benchmark existing installations as well as propose and set new (EU) legislation schemes. This work proposes a standardized classification (including names) of agrivoltaic systems, which is usable worldwide. The classification is based on the application, system, the farming type, PV structure and flexibility. These elements makes it possible to describe and categorize each existing agrivoltaic installation properly. This work suggests to mention each sub-category (for example: static stilted orchard agrovoltaic system) in future research papers or documents to order to better compare (rangevoltaic <=> agrovoltaic) and benchmark new installed installations. When comparing agrivoltaics, the use of the proposed seven KPIs will help to make meaningful comparisons and grounded decisions in case of possible new installations.
A system combining soil grown crops with photovoltaic panels (PV) installed several meters above the ground is referred to as agrivoltaic systems. In this work a patented agrivoltaic solar tracking system named Agrovoltaico®, was examined in combination with a maize crop in a simulation study. To this purpose a software platform was developed coupling a radiation and shading model to the generic crop growth simulator GECROS. The simulation was conducted using a 40-year climate dataset from a location in North Italy, rainfed maize and different Agrovoltaico configurations (that differ according to panel density and sun-tracking set up). Control simulations for an irrigated maize crop under full light were added to results. Reduction of global radiation under the Agrovoltaico system was more affected by panel density (29.5% and 13.4% respectively for double density and single density), than by panel management (23.2% and 20.0% for suntrack and static panels, respectively). Radiation reduction, under Agrovoltaico, affected mean soil temperature, evapotranspiration and soil water balance, on average providing more favorable conditions for plant growth than in full light. As a consequence, in rainfed conditions, average grain yield was higher and more stable under agrivoltaic than under full light. The advantage of growing maize in the shade of Agrovoltaico increased proportionally to drought stress, which indicates that agrivoltaic systems could increase crop resilience to climate change. The benefit of producing renewable energy with Agrovoltaico was assessed using the Land Equivalent Ratio, comparing the electric energy produced by Agrovoltaico cultivated with biogas maize to that produced by a combination of conventional ground mounted PV systems and biogas maize in monoculture. Land Equivalent Ratio was always above 1, it increased with panel density and it was higher with sun tracking than with static panels. The best Agrivoltaico scenario produced twice as much energy, per unit area, as the combination of ground mounted PV systems and biogas maize in monoculture. For this Agrivoltaico can be considered a valuable system to produce renewable energy on farm without negatively affecting land productivity.
Researchers present here a novel ecosystems approach—agrivoltaics—to bolster the resilience of renewable energy and food production security to a changing climate by creating a hybrid of colocated agriculture and solar PV infrastructure, where crops are grown in the partial shade of the solar infrastructure. They suggest that this energy- and food-generating ecosystem may become an important—but as yet quantitatively uninvestigated—mechanism for maximizing crop yields, efficiently delivering water to plants and generating renewable energy in dryland environments. We demonstrate proof of concept for agrivoltaics as a food–energy–water system approach in drylands by simultaneously monitoring the physical and biological dimensions of the novel ecosystem. We hypothesized that colocating solar and agricultural could yield several significant benefits to multiple ecosystem services, including (1) water: maximizing the efficiency of water used for plant irrigation by decreasing evaporation from soil and transpiration from crop canopies, and (2) food: preventing depression in photosynthesis due to heat and light stress, thus allowing for greater carbon uptake for growth and reproduction. An additional benefit might be (3) energy: transpirational cooling from the understorey crops lowering temperatures on the underside of the panels, which could improve PV efficiency. We focused on three common agricultural species that represent different adaptive niches for dryland environments: chiltepin pepper (Capsicum annuum var. glabriusculum), jalapeño (C. annuum var. annuum) and cherry tomato (Solanum lycopersicum var. cerasiforme). We created an agrivoltaic system by planting these species under a PV array—3.3m off the ground at the lowest end and at a tilt of 32°—to capture the physical and biological impacts of this approach. Throughout the average three-month summer growing season we monitored incoming light levels, air temperature and relative humidity continuously using sensors mounted 2.5m above the soil surface, and soil surface temperature and moisture at 5-cm depth. Both the traditional planting area (control) and agrivoltaic system received equal irrigation rates, and we tested two irrigation scenarios—daily irrigation and irrigation every 2d. The amount of incoming photosynthetically active radiation (PAR) was consistently greater in the traditional, open-sky planting area (control plot) than under the PV panels. This reduction in the amount of incoming energy under the PV panels yielded cooler daytime air temperatures, averaging 1.2+0.3 °C lower in the agrivoltaics system over the traditional setting. Night-time temperatures were 0.5+0.4 °C warmer in the agrivoltaics system over the traditional setting (Fig. 2b). Photosynthetic rates, and therefore growth and reproduction, are also regulated by atmospheric dryness, as represented by vapour pressure deficit (VPD) where lower VPD indicates more moisture in the air. VPD was consistently lower in the agrivoltaics system than in the traditional growing setting, averaging 0.52+0.15 kPa lower across the growing season. Having documented that an agrivoltaic installation can significantly reduce air temperatures, direct sunlight and atmospheric demand for water relative to nearby traditional agricultural settings, we address several questions regarding impacts of the food–energy–water nexus system.
The specific intent of this study was to draw insight about solar development from participant experience, and responses indicate that the most considerable opportunities and barriers center on social acceptance and public perception issues. Perspectives about the opportunities and barriers to agrivoltaic development were captured via interviews with solar industry professionals, and inductive analysis revealed that interviewees were most focused on opportunities and barriers that correspond with Wüstenhagen et al.’s three dimensions of social acceptance: market, community, and socio-political factors.
Worldwide, water is becoming scarcer and more expensive due to the effects of climate change. Significant adaptation will be necessary to ensure adequate supply and efficient use of a diminishing resource. This reduction in the supply of water will affect agriculture and will require a change in focus from increasing productivity of land to increasing productivity per unit of water consumed.
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