Renewable energy is a promising alternative to fossil fuel based energy, but its development can require a complex set of environmental tradeoffs. A recent increase in solar energy systems, especially large, centralized installations, underscores the urgency of understanding their environmental interactions. Synthesizing literature across numerous disciplines, the researchers review direct and indirect environmental impacts both beneficial and adverse of utility scale solar energy (USSE) development, including impacts on biodiversity, land use and land cover change, soils, water resources, and human health. Additionally, they review feedbacks between USSE infrastructure and land atmosphere interactions and the potential for USSE systems to mitigate climate change. Several characteristics and development strategies of USSE systems have low environmental impacts relative to other energy systems, including other renewables. We show opportunities to increase USSE environmental co benefits, the permitting and regulatory constraints and opportunities of USSE, and highlight future research directions to better understand the nexus between USSE and the environment. Increasing the environmental compatibility of USSE systems will maximize the efficacy of this key renewable energy source in mitigating climatic and global environmental change. Utility scale solar energy systems are on the rise worldwide, an expansion fueled by technological advances, policy changes, and the urgent need to reduce both our dependence on carbon intensive sources of energy and the emission of greenhouse gases to the atmosphere. Recently, a growing interest among scientists, solar energy developers, land managers, and policy makers to understand the environmental impacts both beneficial and adverse of USSE, from local to global scales, has engendered novel research and findings. This review synthesizes this body of knowledge, which conceptually spans numerous disciplines and crosses multiple interdisciplinary boundaries. The disadvantageous environmental impacts of USSE have not heretofore been carefully evaluated nor weighted against the numerous environmental benefits particularly in mitigating climate change and co benefits that solar energy systems offer. Indeed, several characteristics and development strategies of USSE systems have low environmental impacts relative to other energy systems, including other renewable energy technologies. Major challenges to the widespread deployment of USSE installations remain in technology, research, and policy. Overcoming such challenges, high lighted in the previous sections, will require multidisciplinary approaches, perspectives, and collaborations. This review serves to induce communication across relatively disparate disciplines but intentional and structured coordination will be required to further advance the state of knowledge and maximize the environmental benefits of solar energy systems at the utility scale.
Tag Archive for: Agrivoltaics
The avenues by which Michigan and the United States provide the electricity essential for the economy and quality of life are in urgent need of change to ensure reliability and affordability while reducing the environmental impacts of this generation and improving social equity. These energy transitions are among the greatest challenges facing countries worldwide today. Another salient global challenge is reversing the decline in pollinators, including numerous species of native bees, honey bees, butterflies and birds. Pollinators provide critical ecosystem services but are facing numerous threats. These two grand challenges intersect as stakeholders work to identify the appropriate landscapes and places to develop solar power in Michigan. Agricultural land is desirable for solar installations for reasons that will be explained in this report. The state of Michigan is allowing solar developers to locate, or “site,” solar panels on preserved farmland but only if they develop habitat on this land to support pollinators. Other states are developing or have already developed standards developers must meet before they can advertise solar power plants as pollinator friendly. This intertwines these two urgent challenges in ways that are laudable; however, numerous questions of feasibility and best practices for achieving quality habitat remain unanswered. Multiple types of expertise and experiences from stakeholders from both energy and agricultural domains are required to successfully address these two challenges. In order to effect change, these stakeholders should collaborate more closely to overcome challenges of interpretation, problem definition and costs. This report identifies and characterizes those issues to facilitate stakeholders’ development of more optimal solutions. Overall, we identified several different paradigms through which stakeholders in Michigan viewed the appropriateness of solar power development on farmland. Some stakeholders viewed solar siting as a decision that should be left to an individual landowner because they have private property rights. Moreover, solar leasing would help to diversify farmers’ incomes, reducing the risks from seasonal and price volatility. Some stakeholders even saw solar leasing as part of farmland preservation, as it could enable a struggling farming operation to stay in business and a farmer to continue to own the land leased for solar rather than selling it for housing development. Other stakeholders saw farmland as a public good and opposed using prime farmland for solar power generation. These stakeholders often assumed that solar power could be targeted specifically toward low-quality agricultural land, or urban rooftops and brownfields rather than agricultural lands. For these stakeholders, inclusion of pollinator habitat and other multi-land uses tended to improve their opinion of solar power.
Threats to pollinators may have profound consequences for ecosystem health as well as our food systems. Concerns about pollinator declines and associated repercussions have led to increased efforts by non-governmental organizations and both public and private sectors to reduce threats to pollinators. One of the most iconic pollinator species, the monarch butterfly (Danaus plexippus plexippus), is recognized and celebrated by people throughout North America; the butterfly’s annual migration stretches from southern Canada to Mexico, covering most of the lower 48 United States during the spring and summer. But monarchs are in trouble. The overwintering population in central Mexico has declined by ~80% since the 1990s. The overwintering population in coastal California has declined by 97% since the 1980s and, in winter of 2018–2019, the population crashed to a mere 0.6% of its historic size. Threatened by habitat loss, insecticides and herbicides, climate change, and other stressors, the species is now being considered for listing under the U.S. Endangered Species Act. Contributions to species conservation efforts can therefore be investments toward helping a species rebound and averting a listing. Electric power companies have an opportunity to play a part in the monarch’s recovery. They own and/or manage a substantial amount of land and associated natural resources across North America, including transmission and distribution rights-of-way (ROW), solar fields, wind fields, buffer areas surrounding power plants and substations, and “surplus” land holdings. These acres hold the potential to create a network of habitat to support monarchs and other pollinators across their breeding range. Together, power companies have an opportunity to make a difference by considering the needs of these important animals when managing habitat and revegetating land.
This guide has been developed to share knowledge and learnings from agrisolar practices around Australia and the world, to assist proponents of utility-scale solar, and the landholders and farmers who work with them, to integrate agricultural activities into solar farm projects. As solar grazing is the dominant form of agrisolar for utility-scale solar, this guide has a strong focus on sharing the knowledge and learnings from Australian projects that have integrated solar grazing practices to date, providing case studies from solar farms currently employing solar grazing, information on the benefits of solar grazing for proponents and farmers, and practical guidance for both farmers and proponents considering solar grazing. A further aim is to contribute to the local knowledge of trends and research from international markets about a broader range of agrisolar models which could be considered for the Australian context. With the deployment of large utility-scale solar farms commencing in Australia from around 2015 onwards, the local experience of agrisolar practices is still developing and currently dominated by the practice of sheep grazing on solar farms. The first known Australian solar farm to implement agrisolar practice was the Royalla Solar Farm which began grazing sheep in 2015. Since then, there have been over a dozen solar farms that have introduced grazing, and it has proved to be an effective partnership for both solar farm proponents and graziers. ‘Solar grazing’, as it is known, is the most prevalent form of complementary land use for utility-scale solar farms. At present, where other forms of agrisolar are being pursued in horticulture, viticulture, aquaculture and cropping, it is typically at a much smaller (ie. nonutility) scale.
Agrivoltaic systems (AVS) offer a symbiotic strategy for co-location sustainable renewable energy and agricultural production. This is particularly important in densely populated developing and developed countries, where renewable energy development is becoming more important; however, profitable farmland must be preserved. As emphasized in the Food-Energy-Water (FEW) nexus, AVS advancements should not only focus on energy management, but also agronomic management (crop and water management). The researchers critically review the important factors that influence the decision of energy management (solar PV architecture) and agronomic management in AV systems. The outcomes show that solar PV architecture and agronomic management advancements are reliant on (1) solar radiation qualities in term of light intensity and photosynthetically activate radiation (PAR), (2) AVS categories such as energy-centric, agricultural-centric, and agricultural-energy-centric, and (3) shareholder perspective (especially farmers). Next, several adjustments for crop selection and management are needed due to light limitation, microclimate condition beneath the solar structure, and solar structure constraints. More importantly, a systematic irrigation system is required to prevent damage to the solar panel structure. The advancements of AVS technologies should not only focus on energy management, but also food (agriculture) and water management, as these three factors are nexus domains. Since the management of agriculture (crop) and water are parts of agronomic management, future enhancements should emphasize the importance of balancing the two. The agronomic management in AV systems that requires improvement includes crop selection recommendations, improved crop management guidelines, and a systematic irrigation system that minimizes environmental impacts caused by excess water and subsequent agrichemical leaching that could affect the solar PV structure. In conclusion, the advancements of AVS technology are expected to reduce reliance on nonrenewable fuel sources and mitigate the effects of global warming, as well as addressing the food-energy-water nexus’s demands.
Recognizing the growing interest in the application of organic photovoltaics (OPVs) with greenhouse crop production systems, in this study we used flexible, roll-to-roll printed, semitransparent OPV arrays as a roof shade for a greenhouse hydroponic tomato production system during a spring and summer production season in the arid southwestern U.S. The wavelength-selective OPV arrays were installed in a contiguous area on a section of the greenhouse roof, decreasing the transmittance of all solar radiation wavelengths and photosynthetically active radiation (PAR) wavelengths to the OPV-shaded area by approximately 40% and 37%, respectively. Microclimate conditions and tomato crop growth and yield parameters were measured in both the OPV-shaded (‘OPV’) and non-OPV-shaded (‘Control’) sections of the greenhouse. The OPV shade stabilized the canopy temperature during midday periods with the highest solar radiation intensities, performing the function of a conventional shading method. Although delayed fruit development and ripening in the OPV section resulted in lower total yields compared to the Control section, after the fourth (of 10 total) harvests, the average weekly yield, fruit number, and fruit mass were not significantly different between the treatment (OPV-shaded) and control group. Light use efficiency (LUE), defined as the ratio of total fruit yield to accumulated PAR received by the plant canopy, was nearly twice as high as the Control section, with 21.4 g of fruit per mole of PAR for plants in the OPV-covered section compared to 10.1 g in the Control section. Overall, this study demonstrated that the use of semi-transparent OPVs as a seasonal shade element for greenhouse production in a high-light region is feasible. However, a higher transmission of PAR and greater OPV device efficiency and durability could make OPV shades more economically viable, providing a desirable solution for co-located greenhouse crop production and renewable energy generation in hot and high-light intensity regions.
This document focuses specifically on solar energy generation that is designed to be compatible with continued farming, whereby little or no land is taken out of production. Primary agricultural soils are those defined as having the best combination of physical and chemical characteristics for producing food, feed, forage, fiber and oilseed crops. Because of the value of these soils from a productivity standpoint, it is generally desirable to protect them from uses that would otherwise remove them from agricultural use. As is illustrated in the case studies, farming-friendly solar is possible. In the examples, several farms have married on-farm solar with rotational grazing of livestock. Another has located their solar system in a buffer area required as part of their organic certification. As planners, it is important not to simply reject the concept of solar on farms or farmland out of hand. Instead, it is needed to consider how these systems can benefit farmers and how they can be utilized in conjunction with active farming to achieve energy goals and protect the viability of agriculture in communities. All of these farmers were pleased with the arrangement they had made for the dual purposes of grazing and providing land space for solar panel arrays. Yet each one of them also mentioned a deep commitment to preserving the best agricultural land for agricultural uses first – and thus the common refrain of thinking it all through before any breaking of ground. The structures are large and change how the land is used. All encouraged the idea of using lower-impact places such as a roof or land that cannot be used for agricultural purposes, first. And secondly, the importance of a revenue source to the farm/farmer for the use of that land supporting the solar array.
This report explores the synergies between farming and solar photovoltaics with the premises that agricultural production on farmland should be maintained and farm profitability and soil health should be improved. Instead of focusing on solar siting, this report explores whether a strong case can be made from a public policy point of view for developing solar so that it helps to preserve and improve farmland and the ecosystem in which it is located, while enabling achievement of both energy system and food system goals. Three examples, using Maryland data, analyzed in the report illustrate the potential of this dual farming-plus-solar approach, with solar being on 10% or less of the farm operation: (i) solar on 100 acres leased from a 1,000 acre corn-soy commodity crop operation; (ii) solar owned by the farmer on 16 acres of a 300-acre dairy-grazing operation; (iii) solar on one-acre of a ten-acre horticultural farm. In each case profits increase substantially. Farm economic resilience is improved because solar revenues are independent of the vagaries of weather and crop markets. While the examples are Maryland-specific, the approach for analyzing dual-use solar is broadly applicable elsewhere in the United States.
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.
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 LATEST
Case Study: Fiddlehead FarmsNovember 21, 2024 - 8:24 am
SCAPES Agrivoltaics Survey November 12, 2024 - 4:29 pm
AgriSolar News Roundup: Agrisolar Development, Aquavoltaics in Taiwan, Illinois Solar Grazing November 12, 2024 - 9:46 am
Case Study: Existing Solar as Farmland Access for Emerging Farmers October 9, 2024 - 11:55 am