Associating solar photovoltaic panels with crop cultivation on the same land area can be called as agrivoltaic systems (AVS). It will achieve a 60 to 70 percent increase of the overall land productivity in AVS, showing high production potential and a field of study with great research value. The aim of the present study is to solve the problem that how to determine appropriate crops for different areas under solar panels. First, for the convenience of analyzing an AVS, we suggest that a representative small part of the whole system, that is, an agrivoltaic unit (AVU), can be defined to describe the characteristic the characteristic of the whole system, which is suitable for various types of AVS. Then, the novel concept of a multiparameter-matrix (M-matrix) is proposed and modeled as the description of the specific climate factors of an AVS. The application of the AVU and M-matrix is also essential for those mixed production systems combining agriculture and buildings, such as city viaduct greening, plant factory, etc. Finally, the suitability model of crops for AVS is established, and winter wheat is selected as an example for calculation. A criterion is given as the theoretical foundation of crop selection. This idea opens new areas of research in AVS.
The spherical micro-cells are a semi-transparent photovoltaic (PV) technology which can contribute to improve the sustainability of greenhouse systems. Previous prototypes were tested in laboratory conditions, but the size was not suitable for the greenhouse roof application. In this work, a new prototype has been developed and tested on a real greenhouse roof. The semi-transparent PV module (STM) was composed by 4800 spherical silicon micro-cells (1.2mm diameter) sandwiched between glass plates and integrated on a greenhouse roof with 26.5° slope. The STM was 910mm long and 610mm wide to match the size of the greenhouse framework. The percentage of the STM area covered with micro-cells was 2.3%, reaching 9.7% considering the metallic conductors. The cell density was 2 cells cm−2 and the measured perpendicular light transmissivity of the semi-transparent area was 73%. The characteristics of the prototype were compared with those of a conventional planar multi-crystalline silicon module (CPM). The module conversion efficiency was steadily around 0.2% over wide incident sunlight angle. The micro-cells never completely eclipse the incident sunlight when observed from more than 1m distance from the roof, keeping the eclipsing level at 9.7%. The yield factor of the STM was slightly higher than the CPM because of the isotropic properties of the spherical cells, which are able to use both the sky-incident and the ground-reflected irradiation for energy production, irrespective of the module slope. The prototype STM is promising for greenhouse roof applications and its performance can be improved by increasing the conversion efficiency.
|Author||Marco Cossu, Akira Yano, Zhi Li, Mahiro Onoe, Hidetoshi Nakamura, Toshinori Matsumoto, Josuke Nakata|
|Citation||Marco Cossu, Akira Yano, Zhi Li, Mahiro Onoe, Hidetoshi Nakamura, Toshinori Matsumoto, Josuke Nakata. 2016. Advances on the semi-transparent modules based on micro solar cells: First integration in a greenhouse system. Applied Energy. 162:1042-1051.|
|Topic||Energy Production, Greenhouse, Novel Solar Technologies, Shading and Light Patterns|
In view of future requirement of both energy and food, agri-voltaic system (AVS) has been proposed as a “mixed
systems associating solar panels and crop at the same time on the same land area”. Considering the available land area between
PV rows and wash out water from PV panels along with harvested rainwater from panel, few crops which can be grown in
agri-voltaic system were screened based on their height, water requirement and shade tolerance characteristics. However, for
future establishment of agri-voltaic system in India, performance of crops at different agro-climatic zones needs to be carried
out through field experimentation.
Aggressive growth of land-based solar photovoltaic (PV) farms can create a land use conflict with agricultural production. Fortunately, this issue can be resolved using the concept of agrivoltaics, which is co-development of land area for both solar PV and agriculture. To investigate and quantify PV generation potential, without significantly harming agriculture output, this study explores the viability of agrivoltaic farms deployment on existing grape farms in India. Considering the shade tolerance of grapes, an techno-economicanalysis is run for the installation of PV systems in the area available between the trellises on a grape farm. The electrical energy generation potential is determined per unit area and economic benefits for the cultivators is quantified over a number of design options. The results show the economic value of the grape farms deploying the proposed agrivoltaic systems may increase more than 15 times as compared to conventional farming, while maintaining approximately the same grape production. If this dual use of land is implemented nationwide, it can make a significant impact by generating over 16,000GWh electricity, which has the potential of meeting the energy demands of more than 15 million people. In addition, grape-based agrivoltaics can be implemented in rural areas to enable village electrification.
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 sun-track 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.
The vulnerabilities of our food, energy and water systems to projected climatic change make building resilience in renewable energy and food production a fundamental challenge. We investigate a novel approach to solve this problem by creating a hybrid of colocated agriculture and solar photovoltaic (PV) infrastructure. We take an integrative approach—monitoring microclimatic conditions, PV panel temperature, soil moisture and irrigation water use, plant ecophysiological function and plant biomass production within this ‘agrivoltaics’ ecosystem and in traditional PV installations and agricultural settings to quantify trade-offs. We find that shading by the PV panels provides multiple additive and synergistic benefits, including reduced plant drought stress, greater food production and reduced PV panel heat stress. The results presented here provide a foundation and motivation for future explorations towards the resilience of food and energy systems under the future projected increased environmental stress involving heat and drought.
|Author||Greg A. Barron-Gafford, Mitchell A. Pavao-Zuckerman, Rebecca L. Minor, Leland F. Sutter, Isaiah Barnett-Moreno, Daniel T. Blackett, Moses Thompson, Kirk Dimond, Andrea K. Gerlak, Gary P. Nabhan, Jordan E. Macknick|
|Citation||Greg A. Barron-Gafford, Mitchell A. Pavao-Zuckerman, Rebecca L. Minor, Leland F. Sutter, Isaiah Barnett-Moreno, Daniel T. Blackett, Moses Thompson, Kirk Dimond, Andrea K. Gerlak, Gary P. Nabhan, Jordan E. Macknick. 2019. Agrivoltaics provide mutual benefits across the food–energy–water nexus in drylands. Nature Sustainability. 2:848–855.|
|Topic||Agricultural Yields, Design Configurations, Energy Production, Environmental Impacts, Microclimate|
The expansion of renewable energies aims at meeting the global energy demand while replacing fossil fuels. However, it requires large areas of land. At the same time, food security is threatened by the impacts of climate change and a growing world population. This has led to increasing competition for limited land resources. In this context, the combination of photovoltaics and plant production — often referred to as agrophotovoltaic (APV) or agrivoltaic systems — has been suggested as an opportunity for the synergistic combination of renewable energy and food production. Although this technology has already been applied in various commercial projects, its practicability and impact on crop production have hardly been investigated. In this review, we give a short summary of the current state of the art and prospective opportunities for the application of APV systems. In addition, we discuss microclimatic alterations and the resulting impacts of APV on crop production. Our main findings are that (1) crop cultivation underneath APV can lead to declining crop yields as solar radiation is expected to be reduced by about one third underneath the panels. However, microclimatic heterogeneities and their impact on crop yields are missing reference and thus, remain uncertain. (2) Through combined energy and crop production, APV can increase land productivity by up to 70%. (3) Given the impacts of climate change and conditions in arid climates, potential benefits are likely for crop production through additional shading and observed improvements of water productivity. (4) In addition, APV enhances the economic value of farming and can contribute to decentralized, off-grid electrification in developing and rural areas, thus further improving agricultural productivity. As such, APV can be a valuable technical approach for more sustainable agriculture, helping to meet current and prospective needs of energy and food production and simultaneously sparing land resources.
|Author||Axel Weselek, Andrea Ehmann, Sabine Zikeli, Iris Lewandowski, Stephan Schindele & Petra Högy|
|Citation||Axel Weselek, Andrea Ehmann, Sabine Zikeli, Iris Lewandowski, Stephan Schindele & Petra Högy. 2019. Agrophotovoltaic systems: applications, challenges, and opportunities. A review. Agronomy for Sustainable Development volume. 39:35.|
|Topic||Agricultural Yields, Design Configurations, Environmental Impacts, Hydrology, Soil, Microclimate, Greenhouse, Plant Physiology, Shading and Light Patterns|
This study introduces a novel algorithm to estimate the cumulated global radiation inside photovoltaic (PV) greenhouses at the desired time interval. The direct and diffuse radiation were calculated on several observations points (OPs) inside the PV greenhouse. The PV panels were assimilated to polygons that can overlap the sun path seen from a specific OP. The algorithm was tested in a greenhouse with 50% PV cover ratio on the roof. The results were showed as the percentage ratio of the cumulated yearly global radiation with and without PV array on the roof (GGR), and used to draw maps of light distribution on different canopy heights (from 0.0 to 2.0m). The maps displayed the variability of the light distribution and the most adversely affected zones inside the PV greenhouse. The yearly GGR increased with the canopy height on the zones under the plastic cover (GGR from 59% at 0.0m to 73% at 2.0m), and decreased under the PV cover (GGR from 57% at 0.0m to 40% at 2.0m). Most zones close to the side walls and the gable walls were the least affected by shading on all canopy heights. The different light distribution on the canopy heights showed that the incident solar energy on the crop changes consistently, according to the growth stage of the plants. The algorithm can be applied to several PV greenhouse types and may provide a decision support tool for the identification of the most suitable plant species, based on their light requirements.
|Author||Marco Cossu, Luigi Ledda, Giulia Urracci, Antonella Sirigu, Andrea Cossu, Lelia Murgia, Antonio Pazzona, Akira Yano|
|Citation||Marco Cossu, Luigi Ledda, Giulia Urracci, Antonella Sirigu, Andrea Cossu, Lelia Murgia, Antonio Pazzona, Akira Yano. 2017. An algorithm for the calculation of the light distribution in photovoltaic greenhouses. Solar Energy. 141:38-48.|
|Topic||Design Configurations, Greenhouse, Novel Solar Technologies, Shading and Light Patterns|
In agrivoltaic systems, photovoltaic (PV) modules are ground-mounted between crops replacing a part of greenhouse or are set below or above the cover film of greenhouse; these can provide solutions with respect to land competition and climate change mitigation. These systems have certain additional functions, namely, sunlight sharing, land sharing and power generation, as compared to the conventional agricultural production systems. These new functions are not adequately performed by traditionally used functional units (FUs), such as the mass- or the area-based FU, in agricultural life cycle assessment (LCA). Therefore, this study proposed new FUs for agrivoltaic systems, namely the modified area-based FU and the monetary-based FU. The modified area-based FU was derived by adding area covered by PV modules to the cultivated area addressing the function of land sharing. The monetary-based FU was derived by adding the prices of crops and electricity addressing the function of the system as a producer of differently valued market goods. The traditional area-based FU is based on the function of solar sharing because crop cultivation and power generation share the same sunlight falling on the same land. These new and traditional FUs were applied to a tomato greenhouse, with and without organic photovoltaics, as a case study of Japan. A combination of traditional and new FUs helps to maintain focus on crop production as the primary function of agricultural land and to better understand the environmental impacts of agrivoltaic systems. Finally, as the sharing of sunlight and land happen simultaneously, a method that addresses both these functions while reporting LCA results was considered.
Solar energy installations in arid and semi-arid regions are rapidly increasing due to technological advances and policy support. Although solar energy provides several benefits such as reduction of greenhouse gases, reclamation of degraded land, and improved quality of life in developing countries, the deployment of large-scale renewable energy infrastructure may negatively impact land and water resources. Meeting the ever-expanding energy demand with limited land and water resources in the context of increasing demand for alternative uses such as agricultural and domestic consumption is a major challenge. The goal of this study was to explore opportunities to colocate solar infrastructures and agricultural crops to maximize the efficiency of land and water use. We investigated the energy inputs/outputs, water use, greenhouse gas emissions, and economics of solar installations in northwestern India in comparison to aloe vera cultivation, another widely promoted and economically important land use in these systems. The life cycle analyses show that the colocated systems are economically viable in some rural areas and may provide opportunities for rural electrification and stimulate economic growth. The water inputs for cleaning solar panels are similar to amounts required for annual aloe productivity, suggesting the possibility of integrating the two systems to maximize land and water use efficiency. A life cycle analysis of a hypothetical colocation indicated higher returns per m3 of water used than either system alone. The northwestern region of India has experienced high population growth in the past decade, creating additional demand for land and water resources. In these water-limited areas, coupled solar infrastructure and agriculture could be established in marginal lands with low water use, thus minimizing the socioeconomic and environmental issues resulting from cultivation of economically important non-food crops (e.g., aloe) in prime agricultural lands.
|Author||Sujith Ravi, Jordan Macknick, David Lobell, Christopher Field, Karthik Ganesan, Rishabh Jain, Michael Elchinger, Blaise Stoltenberg|
|Citation||Sujith Ravi, Jordan Macknick, David Lobell, Christopher Field, Karthik Ganesan, Rishabh Jain, Michael Elchinger, Blaise Stoltenberg. 2016. Colocation opportunities for large solar infrastructures and agriculture in drylands. Applied Energy. 165:383-392.|
|Topic||Agricultural Yields, Design Configurations, Energy Production|
The need for new sources of renewable energies and the rising price of fossil fuels have induced the hope that agricultural crops may be a source of renewable energy for the future. We question in this paper the best strategies to convert solar radiation into both energy and food. The intrinsic efficiency of the photosynthetic process is quite low (around 3%) while commercially available monocristalline solar photovoltaic (PV) panels have an average yield of 15%. Therefore huge arrays of solar panels are now envisaged. Solar plants using PV panels will therefore compete with agriculture for land. In this paper, we suggest that a combination of solar panels and food crops on the same land unit may maximise the land use. We suggest to call this an agrivoltaic system. We used Land Equivalent Ratios to compare conventional options (separation of agriculture and energy harvesting) and two agrivoltaic systems with different densities of PV panels. We modelled the light transmission at the crop level by an array of solar panels and used a crop model to predict the productivity of the partially shaded crops. These preliminary results indicate that agrivoltaic systems may be very efficient: a 35–73% increase of global land productivity was predicted for the two densities of PV panels. Facilitation mechanisms similar to those evidenced in agroforestry systems may explain the advantage of such mixed systems. New solar plants may therefore combine electricity production with food production, especially in countries where cropping land is scarce. There is a need to validate the hypotheses included in our models and provide a proof of the concept by monitoring prototypes of agrivoltaic systems.
|Author||C. Dupraz, H. Marrou, G. Talbot, L. Dufour, A. Nogier, Y. Ferard|
|Citation||C. Dupraz, H. Marrou, G. Talbot, L. Dufour, A. Nogier, Y. Ferard. 2011. Combining solar photovoltaic panels and food crops for optimising land use: Towards new agrivoltaic schemes. Renewable Energy. 36(10):2725-2732.|
|Topic||Agricultural Yields, Design Configurations|
Land use constraints have motivated investigation into the spatial coexistence of photovoltaics and agriculture. Existing experimental work has emphasized fixed south-facing configurations with traditional commercial panel shapes, and modeling work is sparse. Previous work also concludes that agriculture-photovoltaic (agrophotovoltaic) systems either decrease crop yield or are limited to shade-tolerant crops. In this work, we explore the effects of different PV array configurations and panel designs on field insolation. We find that east-west tracking configurations outperform fixed south-facing configurations due to shadow migration paths. Additionally, we show through optical modeling that utilization of mini-modules in patterned panel designs may create more optimal conditions for plant growth while using the same area of PV, thus improving the land-use efficiency of the agrophotovoltaic system.
|Author||A. Perna, E. K. Grubbs, R. Agrawal, P. Bermel|
|Citation||A. Perna, E. K. Grubbs, R. Agrawal, P. Bermel,. 2019. Design Considerations for Agrophotovoltaic Systems: Maintaining PV Area with Increased Crop Yield. In: 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC); 2019/06/19; Chicago. Chicago, IL: IEEE; p. 0668-0672|
|Jurisdiction||State: California, Texas|
|Topic||Design Configurations, Novel Solar Technologies, Shading and Light Patterns|
This paper proposes ‘agrivoltaic’ system development within Phoenix Metropolitan Statistical Area (MSA) with the objective to generate clean energy in the agricultural lands using solar PV (Photovoltaics) systems thus reducing land commitment and also preserving the agricultural land in the process. Phoenix MSA comprises of two of the fastest growing counties in United States. The study finds that with half density panel distribution, private agricultural lands in the APS (Arizona Public Service) service territory can generate about 8 times the current residential energy demand and 3.4 times the current total energy requirements of the residential, commercial and industrial sectors in the MSA. The Indian Reservation land in the SRP (Salt River Project) service territory has the capacity to generate all of the current residential energy requirement. Most of the agricultural land lies within 1 mile of the 230 and 500kV transmission lines and is capable of producing 137.5 and 77.5 million MWh of energy. However, with half density panel distribution, an agricultural land received about 60% of direct sunlight compared to a land with no panels. Farmlands have the capacity to generate energy which is significantly more than that required for crop production. Analysis shows that about 50% of the agricultural land sales would have made up for the price of the sale within 2 years with agrivoltaic systems. The effect of preserving the agricultural land and creating a natural growth boundary on urban growth patterns in the rapidly sprawling Phoenix MSA is left as scope for future studies.
In this study, the energy balance for a prototype dynamic photovoltaic greenhouse was determined for days with completely clear skies during the summer. The rotation of photovoltaic panels along the longitudinal axis was the unique feature of the prototype. Inside the greenhouse, the degree of shading most suitable for the requirements of the crop, the cultivation period, the latitude of the site and the climatic conditions was selected by the rotation of the panels. To avoid energy losses from the reflection caused by unfavourably positioned photovoltaic panels, the panels were provided with highly reflective aluminium mirrors. To evaluate the possibility of using the dynamic photovoltaic greenhouse prototype as a passive cooling system, the energy balance was determined. Based on the results, the use of photovoltaic elements offers an alternative perspective for both the shading of greenhouses and the production of electricity in periods of heat and in areas with a warm climate. With planning that considers the type of crop, geographic coordinates, length of the cultivation period and local weather conditions, the use of this structure can reconcile agricultural production with the production of energy from renewable sources.
Agrivoltaics co-locate crops with solar photovoltaics (PV) to provide sustainability benefits across land, energy, and water systems. Policies supporting a switch from irrigated farming to rainfed, grid-connected agrivoltaics in regions experiencing groundwater stress can mitigate both groundwater depletion and CO2 from electricity generation. Here, hydrology, crop, PV, and financial models are integrated to assess the economic potential for rainfed agrivoltaics in groundwater-stressed regions. The analysis reveals 11.2–37.6 PWh/yr of power generation potential, equivalent to 40%–135% of the global electricity supply in 2018. Almost 90% of groundwater depletion in 2010 (∼150 km3) occurred where the levelized cost for grid-connected rainfed agrivoltaic generation is 50–100 USD/MWh. Potential revenue losses following the switch from irrigated to rainfed crops represent 0%–34% of the levelized generation cost. Future cost–benefit analysis must value the avoided groundwater stress from the perspective of long-term freshwater availability.
Solar photovoltaic (PV) technology is being deployed at an unprecedented rate. However, utility-scale solar energy development is land intensive and its large-scale installation can have negative impacts on the environment. In particular, solar energy infrastructure can require extensive landscape modification that transforms soil ecological functions, thereby impacting hydrologic, vegetative, and carbon dynamics. However, reintroducing native vegetation to solar PV sites may be a means of restoring their soils. To this end, we investigated critical soil physical and chemical parameters at a revegetated photovoltaic array and an adjacent reference grassland in Colorado, United States. Seven years after revegetation, we found that carbon and nitrogen remained lower in the PV soil than in the reference soil and contained a greater fraction of coarse particles. We also found that the PV modules introduced heterogeneity in the soil moisture distribution, with precipitation accumulating along the lower edges of panels. The redistribution of soil moisture by panel arrays could potentially be used in concert with planting strategies to maximize plant growth or minimize soil erosion, and should be considered when evaluating the potential to co-locate vegetation with solar infrastructure.
|Author||Choi Chong Seok, Cagle Alexander E., Macknick Jordan, Bloom Dellena E., Caplan Joshua S., Ravi Sujith|
|Citation||Choi Chong Seok, Cagle Alexander E., Macknick Jordan, Bloom Dellena E., Caplan Joshua S., Ravi Sujith. 2020. Effects of Revegetation on Soil Physical and Chemical Properties in Solar Photovoltaic Infrastructure. Frontiers in Environmental Science. 8(140):1-9.|
|Topic||Environmental Impacts, Groundcover, Hydrology, Soil|
The use of renewable energy for greenhouse environment control to replace or reduce the consumption of fuel and power-line electricity is an important objective for sustainable greenhouse crop production. This study was undertaken to apply a solar photovoltaic (PV) array to supply electricity for greenhouse environment control. The PV array was mounted inside the south roof of an east–west oriented single-span greenhouse, in which Welsh onion (Allium fistulosum L.) was cultivated hydroponically. Effects of PV-array shading on the Welsh onion growth were assessed. Two PV-array formations were tested: straight-line and checkerboard. For each arrangement, the PV array covered 12.9% of the greenhouse roof area. Beside the PV greenhouse, a control greenhouse was built with identical dimensions and orientation to those of the PV greenhouse. Welsh onion was cultivated also in the control greenhouse. The straight-line arranged PV-array (PVs array) cast shadows on a specific area of the cultivated plants continuously during the growth period. The fresh weight (FW) and dry-matter weight (DW) of Welsh onion cultivated under the PVs array shadow were significantly less than those of Welsh onion cultivated in the control greenhouse. The checkerboard PV-array (PVc array) cast shadows in the PVc greenhouse intermittently during growth. Consequently, the inhibitory effects of the PV-array shading on the FW and DW accumulations of Welsh onion were diminished. The electrical energy generated by the PVc array was comparable to that of the PVs array, which is another advantage of the PVc array.
|Author||Masayuki Kadowaki, Akira Yano, Fumito Ishizu, Toshihiko Tanaka, Shuji Noda|
|Citation||Masayuki Kadowaki, Akira Yano, Fumito Ishizu, Toshihiko Tanaka, Shuji Noda. 2012. Effects of greenhouse photovoltaic array shading on Welsh onion growth. Biosystems Engineering. 111(3):290-297.|
|Topic||Agricultural Yields, Design Configurations, Energy Production, Costs and Economics, Greenhouse, Plant Physiology, Shading and Light Patterns|
Integration of agriculture and renewable energy resources (RER) is currently a hot topic discussed worldwide based on the need for green energy and sustainable economy. The decreasing trend of global market value for the traditional agricultural commodity such as Rubber and Palm Oil really affected the Gross National Income (GNI) and thus, the government of Malaysia outlined a number of strategic thrusts to boost economic growth. Herbal products have been given sufficient rooms for extension as the first approved Entry Point Projects (EPP1) driver of sustainability. Orthosiphon Stamineus also known as Java Tea is among the five commercialize High-Value Herbal crops (HVHc) and chosen to be deployed under PV arrays based on its sustainability and potential market value. The financial analysis is based on 3-months harvesting cycle with reference to the harvesting coefficience pc and realistic cash flow. The Internal Rate of Return (IRR) is valued at 15.74% that benchmarks positive net return for herbal producers. The cash functions based on Return-on-Investment (ROI) can be achieved after 10 months cycle of production with Net Present Value (NPV) of RM8,863.59. This initiative flows in line with the Cleaner Production (CP) concept of efficient usage of natural resources to minimize waste and pollution. The concept of agro-technology integration is presented with strong financial return for the unused space under PV arrays configured for large scale PV farms.
|Author||N.F. Othman, M.E. Ya'acob, A.S. Abdul-Rahim, Mohd Shahwahid Othman, M.A.M. Radzi, H. Hizam, Y.D. Wang, A.M. Ya'acob, H.Z.E. Jaafar|
|Citation||N.F. Othman, M.E. Ya'acob, A.S. Abdul-Rahim, Mohd Shahwahid Othman, M.A.M. Radzi, H. Hizam, Y.D. Wang, A.M. Ya'acob, H.Z.E. Jaafar. 2015. Embracing new agriculture commodity through integration of Java Tea as high Value Herbal crops in solar PV farms. Journal of Cleaner Production. 91:71-77.|
|Topic||Agricultural Yields, Energy Production, Costs and Economics, Microclimate|
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, we 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, we 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.
|Author||R.R. Hernandez, S.B. Easter, M.L. Murphy-Mariscal, F.T. Maestre, M. Tavassoli, E.B. Allen, C.W. Barrows, J. Belnap, R. Ochoa-Hueso, S. Ravi, M.F. Allen|
|Citation||R.R. Hernandez, S.B. Easter, M.L. Murphy-Mariscal, F.T. Maestre, M. Tavassoli, E.B. Allen, C.W. Barrows, J. Belnap, R. Ochoa-Hueso, S. Ravi, M.F. Allen. 2014. Environmental impacts of utility-scale solar energy. Renewable and Sustainable Energy Reviews. 29:766-779.|
|Strategy||Animal Grazing, Concentrating Solar Power, Conventional Practices, Crop Production, Native/Pollinator-Friendly Vegetation|
|Topic||Environmental Impacts, Groundcover, Policies and Regulations, Siting|
Of the many roles insects serve for ecosystem function, pollination is possibly the most important service directly linked to human well-being. However, land use changes have contributed to the decline of pollinators and their habitats. In agricultural landscapes that also support renewable energy developments such as utility-scale solar energy [USSE] facilities, opportunities may exist to conserve insect pollinators and locally restore their ecosystem services through the implementation of vegetation management approaches that aim to provide and maintain pollinator habitat at USSE facilities. As a first step toward understanding the potential agricultural benefits of solar-pollinator habitat, we identified areas of overlap between USSE facilities and surrounding pollinator-dependent crop types in the United States (U.S.). Using spatial data on solar energy developments and crop types across the U.S., and assuming a pollinator foraging distance of 1.5 km, we identified over 3,500 km2 of agricultural land near existing and planned USSE facilities that may benefit from increased pollination services through the creation of pollinator habitat at the USSE facilities. The following five pollinator-dependent crop types accounted for over 90% of the agriculture near USSE facilities, and these could benefit most from the creation of pollinator habitat at existing and planned USSE facilities: soybeans, alfalfa, cotton, almonds, and citrus. We discuss how our results may be used to understand potential agro-economic implications of solar-pollinator habitat. Our results show that ecosystem service restoration through the creation of pollinator habitat could improve the sustainability of large-scale renewable energy developments in agricultural landscapes.
|Author||Leroy J. Walston, Shruti K. Mishra, Heidi M. Hartmann, Ihor Hlohowskyj, James McCall, Jordan Macknick|
|Publication Date||May 2018|
|Citation||Leroy J. Walston, Shruti K. Mishra, Heidi M. Hartmann, Ihor Hlohowskyj, James McCall, Jordan Macknick. 05/2018. Examining the Potential for Agricultural Benefits from Pollinator Habitat at Solar Facilities in the United States. Environmental Science and Technology. 7566-7576.|
|Strategy||Apiaries, Conventional Practices, Native/Pollinator-Friendly Vegetation|
|Topic||Agricultural Yields, Environmental Impacts, Groundcover, Insect Populations|
The integration of renewable energy sources into greenhouse crop production in southeastern Spain could provide extra income for growers. Wind energy could be captured by small to medium-sized wind turbines, gas could be produced from biomass, and solar energy could be gathered by solar panels. The aim of this study was to examine the effect of flexible solar panels, mounted on top of a greenhouse for electricity production, on yield and fruit quality of tomatoes (Solanum lycopersycum L., cv Daniela). This study was undertaken in a commercial raspa y amagado greenhouse, typical of the Almería region (Spain). Tomato plantlets were planted at a density of 0.75 plants m-2. The flexible solar panels were mounted on two parts of the roof in different arrangements (T1 and T2), each blacking out 9.8 % of its surface area. A control area (T0 arrangement) was fitted with no panels. No difference was found in terms of total or marketable production under these three arrangements, although fruit mean mass and maximum diameter of T0 were significantly greater than T1 and T2. Fruit in T0 matured earlier with more intense color compared with those in T1 and T2. However, these differences had no effect on price as the tomatoes produced under three conditions fell into the same commercial class (G class; diameter 67-81 mm). Solar panels covering 9.8 % roof area of the greenhouse did not affect yield and price of tomatoes despite of their negative effect on fruit size and color.
Associating on the same land area an upper layer of solar panels together with a crop layer at the ground level has been shown to allow significant saving of land resource compared to separate energy and food productions (Marrou et al., 2013a). Indeed, crops can achieve high yield under the fluctuating shade of these agrivoltaic systems. Moreover, under dry Mediterranean climate, microclimate measurements at crop level below these panels suggest that these systems could contribute to alleviate climatic stress and to save water. On two experimental prototypes of these agrivoltaic systems, we combined two complementary approaches to assess the impact of the solar panels cover on crop water use. First we calculated the bulk actual evapotranspiration (AET) of irrigated lettuces and cucumbers grown in agrivoltaic systems and in the full sun, from field measurements using the water balance equation for a crop–soil system. Then, we proposed a conceptual framework to analyze AET modifications in the partial shade and assess the contribution of identified drivers to this change. This conceptual framework breaks AET into two components (plant transpiration and soil evaporation) and four drivers: climatic demand at canopy level (ET0), fraction of radiation intercepted by the vegetation, plant stomatal conductance, and soil surface hydraulic conductance. From specific field measurements, we assessed the contribution of each driver to the variations of evapotranspiration below the photovoltaic panels (PVP), in comparison with the full sun. Crop AET calculated with the first approach (water balance) was reduced in agrivoltaic systems by 10–30% when available light was equal to 50–70% of full sun radiation, with variations according to the weather season. The second approach showed that reduction of evapotranspiration was mainly driven by the reduction of the climatic demand below the solar panels and did not result systematically in an increase of the water use efficiency, depending on the genotypic plant sensibility of dry matter accumulation to shade. The conceptual framework suggest that water use efficiency in agrivoltaic systems could be increased by selecting crop species and varieties with a rapid soil covering, which contributes to increased light capture and to decreased soil evaporation, leaving more water for plant transpiration and thereby for biomass production.
With large‐scale solar photovoltaics in Australia experiencing unprecedented levels of investment, now is a unique opportunity for the national economy and for the communities in regional Australia. Environmental impacts are minimal and community benefits can accrue from both large‐ and utility‐scale solar projects, such as jobs and regional investment. But there are questions for the agricultural sector to consider as these opportunities open up:
To what extent is the concern of energy generation versus food production warranted?
Should large‐scale solar power stations even be built on agricultural land?
The author uses a case study from the Central West of New South Wales (NSW) to explore these issues as well as briefly reviewing critical research into the international development of agrivoltaics.
Rising demand for solar power generation will lead to increased land use competition, and thus to potential economic and social conflict. A solution to this challenge is to produce food and energy within an agrophotovoltaics (APV) system. Since 2017, governments in Japan, France, Massachusetts (USA), South Korea, and China have introduced policies supporting APV implementation. Governments considering APV implementation – e.g. in India and Germany – for evidence-based policy making are demanding information on how levelized cost of electricity (LCOE) of APV differs from that of conventional ground-mounted photovoltaics (PV), as well as on how additional costs associated with APV installation relate to the benefit of maintaining agricultural activity under APV. Data for a techno-economic price-performance ratio calculation has been retrieved from an inter- and transdisciplinary APV case study in Germany. We observed that the LCOE of APV with €0.0828 kWh−1 is 38% higher than that of ground-mounted PV, resulting in an annual cropland preservation price of €9,052 ha−1 a−1. The annual revenue of potato and winter wheat production under APV resulted in a performance of €10,707 ha−1 a−1 and €1,959 ha−1 a−1 respectively, leading to a beneficial price-performance ratio of 0.85 for potato production and, with a ratio of 4.62, a disadvantageous result for winter wheat. Overall, APV is not necessarily recommended in crop rotating systems. However, in combination with permanent cultures – e.g. berries, fruits, or wine grapes – as the price for these types of applications is lower, while at the same time providing higher performance by optimizing techno-ecological synergies.
|Author||Stephan Schindele, Maximilian Trommsdorff, Albert Schlaak, Tabea Obergfell, Georg Bopp, Christian Reise, Christian Braun, Axel Weselek, Andrea Bauerle, Petra Högy, Adolf Goetzberger, Eicke Weber|
|Citation||Stephan Schindele, Maximilian Trommsdorff, Albert Schlaak, Tabea Obergfell, Georg Bopp, Christian Reise, Christian Braun, Axel Weselek, Andrea Bauerle, Petra Högy, Adolf Goetzberger, Eicke Weber. 2020. Implementation of agrophotovoltaics: Techno-economic analysis of the price-performance ratio and its policy implications. Applied Energy. 265:114737.|
|Jurisdiction||Country: Germany, Japan, United States|
|Topic||Agricultural Yields, Design Configurations, Energy Production, Policies and Regulations, Costs and Economics, Novel Solar Technologies|
Agrivoltaic systems, consisting of the combination of photovoltaic panels (PVPs) with crops on the same land, recently emerged as an opportunity to resolve the competition for land use between food and energy production. Such systems have proved efficient when using stationary PVPs at half their usual density. Dynamic agrivoltaic systems improved the concept by using orientable PVPs derived from solar trackers. They offer the possibility to intercept the variable part of solar radiation, as well as new means to increase land productivity. The matter was analysed in this work by comparing fixed and dynamic systems with two different orientation policies. Performances of the resulting agrivoltaic systems were studied for two varieties of lettuce over three different seasons. Solar tracking systems placed all plants in a new microclimate where light and shade bands alternated several times a day at any plant position, while stationary systems split the land surface into more stable shaded and sunlit areas. In spite of these differences, transient shading conditions increased plant leaf area in all agrivoltaic systems compared to full-sun conditions, resulting in a higher conversion of the transmitted radiation by the crop. This benefit was lower during seasons with high radiation and under controlled tracking with more light transmitted to the crop. As expected, regular tracking largely increased electric production compared to stationary PVPs but also slightly increased the transmitted radiation, hence crop biomass. A large increase in transmitted radiation was achieved by restricting solar tracking around midday, which resulted in higher biomass in the spring but was counterbalanced by a lower conversion efficiency of transmitted radiation in summer. As a result, high productivity per land area unit was reached using trackers instead of stationary photovoltaic panels in agrivoltaic systems, while maintaining biomass production of lettuce close or even similar to that obtained under full-sun conditions.
|Author||B. Valle, T. Simonneau, F. Sourd, P. Pechier, P. Hamard, T. Frisson, M. Ryckewaert, A. Christophe|
|Citation||B. Valle, T. Simonneau, F. Sourd, P. Pechier, P. Hamard, T. Frisson, M. Ryckewaert, A. Christophe. 2017. Increasing the total productivity of a land by combining mobile photovoltaic panels and food crops. Applied Energy. 206:1495-1507.|
|Topic||Agricultural Yields, Design Configurations, Energy Production, Microclimate, Plant Physiology, Shading and Light Patterns|
Agrivoltaic systems are multi-output systems where both solar power and crops are produced on the same land. Unlike other land-based photovoltaics (PV), the agrivoltaic PV modules are ground mounted between crops at some height with a certain tilt. Alternatively, PV modules replace part of a greenhouse or are partially set either below or above a covering material. The system could become an important mitigation option for climate change. However, power generation by PV reduces sunlight transmittance and therefore reduces agricultural yield. An allocation method that will address the potential interference of PV with crops is required for life cycle assessment (LCA) to evaluate greenhouse gas mitigation. This study aims to develop a new allocation method (i.e., solar allocation) and compare the LCA results of the new and traditional allocation methods (i.e., system expansion and economic allocation). The partition rate of the solar allocation is derived from the ratio of the active area covered by PV to the greenhouse surface area and light transmittance. These methods were applied to an agrivoltaic tomato production system using protected horticulture with the introduction of organic photovoltaics as a case-study of a system in Japan. The allocation methods considered in the present study could serve as potential methods in assessing life cycle−CO2 emissions. Above all, the solar allocation method can be used for many crops that will be influenced by PVs. Further improvement of the allocation method is required in cases where crop growth is less influenced by PVs (e.g., shadow-tolerant crops or transparent PV).
Photovoltaic systems require large swaths of land that are currently being used for other purposes, such as farming. One option for developing large photovoltaic systems is converting farms that are currently economically unviable into commercial photovoltaic systems. However, this may not always be an economically rational decision as crop prices have the potential to increase over time. Fluctuations in farm income due to changes in crop prices can alter the optimal choice of whether to continue farming or to convert farmland into commercial photovoltaic systems. This study attempts to resolve this issue by proposing a real options framework to value farm production when crop prices are uncertain. By integrating uncertainty into the decision-making process, the value of keeping unprofitable farms operating prior to developing the area into a commercial photovoltaic system is assessed. This helps decision makers understand the extent to which potential income from developing a photovoltaic system should be greater than potential income from farming when deciding on investing in a photovoltaic system. A case study is conducted to examine this framework and to calculate the net present value of a farm in South Korea. The results indicate that although the money lost from continuing to farm is substantial, farmers should defer conversion to a commercial photovoltaic system until a sufficient drop in crop prices occurs. When applying this strategy, the farmer can gain an additional 100% of expected revenue simply by deferring the development decision until having better information on the market prices of crops.
|Author||Byungil Kim, Changyoon Kim, SangUk Han, JuHyun Bae, Jaehoon Jung|
|Citation||Byungil Kim, Changyoon Kim, SangUk Han, JuHyun Bae, Jaehoon Jung. 2020. Is it a good time to develop commercial photovoltaic systems on farmland? An American-style option with crop price risk. Renewable and Sustainable Energy Reviews. 125:1-9.|
|Jurisdiction||Country: South Korea|
|Topic||Agricultural Yields, Energy Production, Siting, Costs and Economics, Technical and Market Potential|
Agrivoltaic systems are mixed systems that associate, on the same land area at the same time, food crops and solar photovoltaic panels (PVPs). The aim of the present study is to assess whether the growth rate of crops is affected in the specific shade of PVPs. Changes in air, ground and crop temperature can be suspected due to the reduction of incident radiation below the photovoltaic shelter. Soil temperature (5cm and 25cm depth), air temperature and humidity, wind speed as well as incident radiations were recorded at hourly time steps in the full sun treatment and in two agrivoltaic systems with different densities of PVPs during three weather seasons (winter, spring and summer). In addition, crop temperatures were monitored on short cycle crops (lettuce and cucumber) and a long cycle crop (durum wheat). The number of leaves was also assessed periodically on the vegetable crops. Mean daily air temperature and humidity were similar in the full sun treatments and in the shaded situations, whatever the climatic season. On the contrary, mean daily soil temperature significantly decreased below the PVPs compared to the full sun treatment. The hourly pattern of crop temperature during day-time (24h) was affected in the shade. In this experiment, the ratio between crop temperature and incident radiation was higher below the PVPs in the morning. This could be due to a reduction of sensible heat losses by the plants (absence of dew deposit in the early morning or reduced transpiration) in the shade compared to the full sun treatment. However, mean daily crop temperature was found not to change significantly in the shade and the growth rate was similar in all the treatments. Significant differences in the leaf emission rate were measured only during the juvenile phase (three weeks after planting) in lettuces and cucumbers and could result from changes in soil temperature. As a conclusion, this study suggests that little adaptations in cropping practices should be required to switch from an open cropping to an agrivoltaic cropping system and attention should mostly be focused on mitigating light reduction and on selection of plants with a maximal radiation use efficiency in these conditions of fluctuating shade.
|Author||H. Marrou, L. Guilioni, L. Dufour, C. Dupraz, J. Wery|
|Citation||H. Marrou, L. Guilioni, L. Dufour, C. Dupraz, J. Wery. 2013. Microclimate under agrivoltaic systems: Is crop growth rate affected in the partial shade of solar panels?. Agricultural and Forest Meteorology. 177:117-132.|
|Topic||Agricultural Yields, Best Practices, Hydrology, Soil, Microclimate|
Construction activities at most large-scale ground installations of photovoltaic (PV) arrays are preceded by land clearing and re-grading to uniform slope and smooth surface conditions to facilitate convenient construction access and facility operations. The impact to original vegetation is usually total eradication followed by installation of a gravel cover kept clear of vegetation by use of herbicides. The degree to which that total loss can be mitigated by some form of revegetation is a subject in its infancy, and most vegetation studies at PV development sites only address weed control and the impact of tall plants on the efficiency of the solar collectors from shading.This study seeks to address this void, advancing the state of knowledge of how constructed PV arrays affect ground-level environments, and to what degree plant cover, having acceptable characteristics within engineering constraints, can be re-established.
|Author||Brenda Beatty, Jordan Macknick, James McCall, Genevieve Braus, Dave Buckner|
|Citation||Brenda Beatty, Jordan Macknick, James McCall, Genevieve Braus, Dave Buckner (National Renewable Energy Laboratory,). 2017. Native Vegetation Performance under a Solar PV Array at the National Wind Technology Center. Golden, CO: National Renewable Energy Laboratory. Report No.: NREL/TP-1900-66218. Contract No.: Contract No. DE-AC36-08GO28308.|
|Strategy||Conventional Practices, Native/Pollinator-Friendly Vegetation|
|Topic||Best Practices, Environmental Impacts, Groundcover|
In this paper we propose a configuration of a solar, e.g., photovoltaic, power plant, which allows for additional agricultural use of the land involved, although the collectors are optimized for solar-energy conversion. If the collectors are not installed directly on the ground, but are elevated by about 2m above the ground with the periodic distance between collector rows of about three times the height of the collectors, one achieves nearly uniform radiation, (integrated over the day), on the ground of a value of about two-thirds of the global radiation without solar collectors. The mathematical relations allowing calculation of the fraction of light reaching the ground under the collector field are derived. Numerical calculations for both the direct and diffuse part of solar radiation are carried out yielding the seasonal and local dependence of this fraction. In addition, we give an outline of the various advantages offered by this configuration.
Large-scale solar facilities have the potential to contribute significantly to national electricity production. Many solar installations are large-scale or utility-scale, with a capacity over 1 MW and connected directly to the electric grid. Large-scale solar facilities offer an opportunity to achieve economies of scale in solar deployment, yet there have been concerns about the amount of land required for solar projects and the impact of solar projects on local habitat. During the site preparation phase for utility-scale solar facilities, developers often grade land and remove all vegetation to minimize installation and operational costs, prevent plants from shading panels, and minimize potential fire or wildlife risks. However, the common site preparation practice of removing vegetation can be avoided in certain circumstances, and there have been successful examples where solar facilities have been co-located with agricultural operations or have native vegetation growing beneath the panels. In this study we outline some of the impacts large-scale solar facilities can have on the local environment, provide examples of installations where impacts have been minimized through co-location with vegetation, characterize the types of colocation, and give an overview of the potential benefits from co-location of solar energy projects and vegetation. The varieties of co-location can be replicated or modified for site-specific use at other solar energy installations around the world. We conclude with opportunities to improve upon our understanding of ways to reduce the environmental impacts of large-scale
|Author||Jordan Macknick, Brenda Beatty, Graham Hill|
|Citation||Jordan Macknick, Brenda Beatty, Graham Hill (National Renewable Energy Laboratory). 2013. Overview of Opportunities for Co-Location of Solar Energy Technologies and Vegetation. Golden, CO: National Renewable Energy Laboratory. Report No.: NREL/TP-6A20-60240. Contract No.: Contract No. DE-AC36-08GO28308.|
|Strategy||Animal Grazing, Apiaries, Conventional Practices, Crop Production, Native/Pollinator-Friendly Vegetation|
|Topic||Agricultural Yields, Best Practices, Design Configurations, Energy Production, Environmental Impacts, Groundcover, Insect Populations, Operations and Maintenance, Siting, Social Issues and Perspectives, Soil|
Photovoltaic industry has been an important development direction of China's strategic emerging industries since 2012, and more and more attentions have been paid to broaden the domestic demand to solve the problem of overcapacity of China's PV industry. Photovoltaic agriculture, the combination of photovoltaic power generation and agricultural activities, is a natural response to supply the green and sustainable electricity for agriculture. There are several main application modes of photovoltaic agriculture such as photovoltaic agricultural greenhouse, photovoltaic breeding, photovoltaic wastewater purification, photovoltaic water pumping and new type rural solar power station. Photovoltaic agriculture can effectively alleviate the contradiction between more population and less land, powerfully promote the development of controlled environmental agriculture, evidently increase economic benefits of farmers, and significantly improve environment due to emissions reduction in China. In recent years, photovoltaic agriculture has a rapid development in China due to powerful support policies, flourishing controlled environmental agriculture, policy-oriented rural electrification and promising electric machinery for greenhouse. Therefore, photovoltaic agriculture provides new opportunity for China's photovoltaic industry, thus not only to solve the dilemma of overcapacity for China's photovoltaic industry effectively, but also to accelerate the development of modern agriculture in China. However, the more theoretical researches and practical exploration must be conducted to optimize the combination of photovoltaic power generation and agricultural planting. And the unified standards must be established to standardize the design and scale of projects of photovoltaic agriculture. Also, photovoltaic enterprises need to produce widely applicable photovoltaic products for agricultural production and farmers’ life.
Based on our search, we believe that this is the first paper to evaluate the use of photovoltaic panels as shade resources for livestock. Photovoltaic panels can provide artificial shades to protect livestock against intense solar radiation while serving as a clean energy source, reducing CO2 emission, and providing an additional source of income to farmers. These benefits foster sustainable livestock farming practices. In this study, we (1) determined livestock shade preference for photovoltaic panels and the classical 80%-blockage cloth material, and (2) quantified the reduction in radiant heat load provided by these shade structures. To determine the shade preference, the behavior of five Corriedale lambs and six Corriedale ewes were observed in a paddock with two shade structures (one with photovoltaic panels and another with an 80%-blockage cloth). The following behavioral activities were determined using the instantaneous scan sampling method each 10-min from 07:00 h to 17:00 h: grazing, ruminating, idling, lying, standing, under the sun, under the shade from photovoltaic panels, and under the shade from cloth. To correlate animal behavior with environmental conditions and to quantify the reduction in radiant heat load provided by these shade structures, the following meteorological variables were recorded: solar radiation (total and short-wave), air temperature, relative humidity, wind speed, and black-globe temperature (in the shades and in the sun). We observed that the animals spent less than 1% of their time under the shade from cloth compared to 38% under the shade from photovoltaic panels and 61% exposed to the sun. Sheep preference for shade projected by photovoltaic panels might be explained by the reduced radiant heat load (approximately lower by 40 W m−2) compared to that from the cloth. When the intensity of solar radiation increased from 250 to 850 W m−2, the time the animals spent outside the shades decreased from 96.7 ± 3.6% to 30.2 ± 6.3%, which was coupled with a similar increase in the time spent in the shade from photovoltaic panels (from 13.0 ± 3.3% to 69.3 ± 6.2%). For the same increase in solar radiation, the energy generated (integrated over 5-min) by the photovoltaic panels increased from 38.8 ± 5.9 to 197.9 ± 3.8 kWh. Over a period of one year, an electric energy of 5.19 MWh (monthly average of 432.33 kWh) was generated and 2.77 tons of CO2 were not emitted to the atmosphere. In economic terms, the electric energy generated in one year was equivalent to a saving of $740.
|Author||Alex Sandro Campos Maia, Eric de Andrade Culhari, Vinícius de França Carvalho Fonsêca, Hugo Fernando Maia Milan, Kifle G Gebremedhin|
|Citation||Alex Sandro Campos Maia, Eric de Andrade Culhari, Vinícius de França Carvalho Fonsêca, Hugo Fernando Maia Milan, Kifle G Gebremedhin. 2020. Photovoltaic panels as shading resources for livestock. Journal of Cleaner Production. 258:1-9.|
|Topic||Energy Production, Costs and Economics, Microclimate, Shading and Light Patterns|
Combining photovoltaic panels (PVPs) and crops on the same land unit were recently proposed as an alternative to the conversion of cropland into photovoltaic plants. This could alleviate the increasing competition for land between food and energy production. In such agrivoltaic systems, an upper layer of PVPs partially shades crops at ground level. The aim of this work was to (i) assess the effect on crop yield of two PVPs densities, resulting in two shade levels equal to 50% and 70% of the incoming radiation and (ii) identify morphological and physiological determinants of the plant response to shade. Experiments were conducted on four varieties of lettuces (two crisphead lettuces and two cutting lettuces), during two seasons. In all cases, the relative lettuce yield at harvest was equal or higher than the available relative radiation. Lettuce yield was maintained through an improved Radiation Interception Efficiency (RIE) in the shade, while Radiation Conversion Efficiency (RCE) did not change significantly. Enhanced RIE was explained by (i) an increase in the total leaf area per plant, despite a decrease in the number of leaves and (ii) a different distribution of leaf area among the pool of leaves, the maximal size of leaves increasing in the shade. Our result provides a framework for the selection of adapted varieties according to their morphological traits and physiological responses to PVP shade, in order to optimize agrivoltaic systems.
Agrivoltaism is the association of agricultural and photovoltaic energy production on the same land area, coping with the increasing pressure on land use and water resources while delivering clean and renewable energy. However, the solar panels located above the cultivated plots also have a seemingly yes unexplored effect on rain redistribution, sheltering large parts of the plot but redirecting concentrated fluxes on a few locations. The spatial heterogeneity in water amounts observed on the ground is high in the general case; its dynamical patterns are directly attributable to the mobile panels through their geometrical characteristics (dimensions, height, coverage percentage) and the strategies selected to rotate them around their support tube. A coefficient of variation is used to measure this spatial heterogeneity and to compare it with the coefficient of uniformity that classically describes the efficiency of irrigation systems. A rain redistribution model (AVrain) was derived from literature elements and theoretical grounds and then validated from experiments in both field and controlled conditions. AVrain simulates the effective rain amounts on the plot from a few forcing data (rainfall, wind velocity and direction) and thus allows real-time strategies that consist in operating the panels so as to limit the rain interception mainly responsible for the spatial heterogeneities. Such avoidance strategies resulted in a sharp decrease in the coefficient of variation, e.g. 0.22 vs. 2.13 for panels held flat during one of the monitored rain events, which is a fairly good uniformity score for irrigation specialists. Finally, the water amounts predicted by AVrain were used as inputs to Hydrus-2D for a brief exploratory study on the impact of the presence of solar panels on rain redistribution at shallow depths within soils: similar, more diffuse patterns were simulated and were coherent with field measurements.
|Author||Yassin Elamri, Bruno Cheviron, Annabelle Mange, Cyril Dejean, François Liron, Gilles Belaud|
|Citation||Yassin Elamri, Bruno Cheviron, Annabelle Mange, Cyril Dejean, François Liron, Gilles Belaud. 2018. Rain concentration and sheltering effect of solar panels on cultivated plots. Hydrology and Earth System Sciences. 22:1-37.|
|Topic||Design Configurations, Hydrology, Soil, Microclimate|
The number of ground-mounted solar parks is increasing across the world in response to energy decarbonisation. Solar parks offer an opportunity to deliver ecosystem co-benefits but there is also a risk that their development and operation may be detrimental to ecosystems. Consequently, we created the Solar Park Impacts on Ecosystem Services (SPIES) decision-support tool (DST) to provide evidence-based insight of the impacts of different solar park management practices on ecosystem services. The SPIES DST is underpinned by 704 pieces of evidence from 457 peer-reviewed academic journal articles that assessed the impacts of land management on ecosystem services, collated through a systematic review. Application to two operational solar parks evidences the commercial relevance of the SPIES DST and its potential to enable those responsible for designing and managing solar parks to maximise the ecosystem co-benefits and minimise detrimental effects. Further, evaluation using data from nine solar parks across the south of England demonstrates the validity of the DST outcomes. With the increasing land take for renewable energy infrastructure, DSTs, such as SPIES, that promote the co-delivery of other ecosystem benefits can help to ensure that the energy transition does not swap climate change for local scale ecosystem degradation, and potentially prompt improvements in ecosystem health.
|Author||R.J. Randle-Boggis, P.C.L. White, J. Cruz, G. Parker, H. Montag, J.M.O. Scurlock, A. Armstrong|
|Citation||R.J. Randle-Boggis, P.C.L. White, J. Cruz, G. Parker, H. Montag, J.M.O. Scurlock, A. Armstrong. 2020. Realising co-benefits for natural capital and ecosystem services from solar parks: A co-developed, evidence-based approach. Renewable and Sustainable Energy Reviews. 125:109775.|
|Jurisdiction||Country: United Kingdom|
|Topic||Environmental Impacts, Research Protocols, Vegetation Performance|
Power demands are set to increase by two-fold within the current century and a high fraction of that demand should be met by carbon free sources. Among the renewable energies, solar energy is among the fastest growing; therefore, a comprehensive and accurate design methodology for solar systems and how they interact with the local environment is vital. This paper addresses the environmental effects of solar panels on an unirrigated pasture that often experiences water stress. Changes to the microclimatology, soil moisture, water usage, and biomass productivity due to the presence of solar panels were quantified. The goal of this study was to show that the impacts of these factors should be considered in designing the solar farms to take advantage of potential net gains in agricultural and power production. Microclimatological stations were placed in the Rabbit Hills agrivoltaic solar arrays, located in Oregon State campus, two years after the solar array was installed. Soil moisture was quantified using neutron probe readings. Significant differences in mean air temperature, relative humidity, wind speed, wind direction, and soil moisture were observed. Areas under PV solar panels maintained higher soil moisture throughout the period of observation. A significant increase in late season biomass was also observed for areas under the PV panels (90% more biomass), and areas under PV panels were significantly more water efficient (328% more efficient).
The recent rapid promotion of renewable energy technology (RET) worldwide may have led to a greater social impact on local communities, where multiple otherwise-small individual units of RET are concentrated in one place, as may occur in the case of small photovoltaic power generating units, for example. This study examines such a case of the dissemination of innovative agrivoltaic systems (AVSs), a system in which photovoltaic power facilities are installed above cultivated farmland, across Japanese rural areas. The paper offers a preliminary sector-wide social impact scoping (SSIS) for potential cumulative social impact of a dissemination policy of AVSs. AVSs were predicted to positively impact many local stakeholders. It was found that AVSs themselves improve energy security as they are, but if particular devices are accommodated, energy security is further improved. Several measures, including providing information to farm operators regarding specific examples of favourable economic outcomes and good agricultural practices, are recommended to mitigate any negative impact of AVS installation. Policymakers should undertake SSIS for RET to reveal the variety of views among otherwise reticent stakeholders so that they can eventually increase the positive impact and mitigate the negative impact of RET.
Solar energy development is a significant driver of land-use change worldwide, and desert ecosystems are particularly well suited to energy production because of their high insolation rates. Deserts are also characterized by uncertain rainfall, high species endemism, and distinct landforms that vary in geophysical properties. Weather and physical features that differ across landforms interact with shade and water runoff regimes imposed by solar panels, creating novel microhabitats that influence biotic communities. Endemic species may be particularly affected because they often have limited distributions, narrow climatic envelopes, or specialized life histories. We used experimental panels to simulate the effects of solar development on microhabitats and annual plant communities present on gravelly bajada and caliche pan habitat, two common habitat types in California's Mojave Desert. We evaluated soils and microclimatic conditions and measured community response under panels and in the open for seven years (2012?2018). We found that differences in site characteristics and weather affected the ecological impact of panels on the annual plant community. Panel shade tended to increase species richness on the more stressful caliche pan habitat, and this effect was strongest in dry years. Shade effects on diversity and abundance also tended to be positive or neutral on caliche pan habitat. On gravelly bajada habitat, panel shade did not significantly affect richness or diversity and tended to decrease plant abundance. Panel runoff rarely affected richness or diversity on either habitat type, but effects on abundance tended to be negative?suggesting that panel rain shadows were more important than runoff from low-volume rain events. These results demonstrate that the ecological consequences of solar development can vary over space and time, and suggest that a nuanced approach will be needed to predict impacts across desert landforms differing in physical characteristics.
Solar energy has the potential to offset a significant fraction of non-renewable electricity demands globally, yet it may occupy extensive areas when deployed at this level. There is growing concern that large renewable energy installations will displace other land uses. Where should future solar power installations be placed to achieve the highest energy production and best use the limited land resource? The premise of this work is that the solar panel efficiency is a function of the location’s microclimate within which it is immersed. Current studies largely ignore many of the environmental factors that influence Photovoltaic (PV) panel function. A model for solar panel efficiency that incorporates the influence of the panel’s microclimate was derived from first principles and validated with field observations. Results confirm that the PV panel efficiency is influenced by the insolation, air temperature, wind speed and relative humidity. The model was applied globally using bias-corrected reanalysis datasets to map solar panel efficiency and the potential for solar power production given local conditions. Solar power production potential was classified based on local land cover classification, with croplands having the greatest median solar potential of approximately 28 W/m2. The potential for dual-use, agrivoltaic systems may alleviate land competition or other spatial constraints for solar power development, creating a significant opportunity for future energy sustainability. Global energy demand would be offset by solar production if even less than 1% of cropland were converted to an agrivoltaic system.
|Author||Elnaz H. Adeh, Stephen P. Good, M. Calaf, Chad W. Higgins|
|Citation||Elnaz H. Adeh, Stephen P. Good, M. Calaf, Chad W. Higgins. 2019. Solar PV Power Potential is Greatest Over Croplands. Scientific Reports. 9:11442.|
|Topic||Energy Production, Environmental Impacts, Siting, Microclimate, Technical and Market Potential|
The purpose of this research was to examine the performance of agrivoltaic systems, which produce crops and electricity simultaneously, by installing stilt-mounted photovoltaic (PV) panels on farmland. As PV power stations enjoy remarkable growth, land occupation with the purpose of establishing solar farms will intensify the competition for land resources between food and clean energy production. The results of this research showed, however, that the stilt-mounted agrivoltaic system can mitigate the trade-off between crop production and clean energy generation even when applied to corn, a typical shade-intolerant crop. The research was conducted at a 100-m2 experimental farm with three sub-configurations: no modules (control), low module density, and high module density. In each configuration, 9 stalks/m2 were planted 0.5 m apart. The biomass of corn stover grown in the low-density configuration was larger than that of the control configuration by 4.9%. Also, the corn yield per square meter of the low-density configuration was larger than that of the control by 5.6%. The results of this research should encourage more conventional farmers, clean energy producers, and policy makers to consider adopting stilt-mounted PV systems, particularly in areas where land resources are relatively scarce.
Increasing energy demands and the drive towards low carbon (C) energy sources has prompted a rapid increase in ground-mounted solar parks across the world. This represents a significant global land use change with implications for the hosting ecosystems that are poorly understood. In order to investigate the effects of a typical solar park on the microclimate and ecosystem processes, we measured soil and air microclimate, vegetation and greenhouse gas emissions for twelve months under photovoltaic (PV) arrays, in gaps between PV arrays and in control areas at a UK solar park sited on species-rich grassland. Our results show that the PV arrays caused seasonal and diurnal variation in air and soil microclimate. Specifically, during the summer we observed cooling, of up to 5.2 °C, and drying under the PV arrays compared with gap and control areas. In contrast, during the winter gap areas were up to 1.7 °C cooler compared with under the PV arrays and control areas. Further, the diurnal variation in both temperature and humidity during the summer was reduced under the PV arrays. We found microclimate and vegetation management explained differences in the above ground plant biomass and species diversity, with both lower under the PV arrays. Photosynthesis and net ecosystem exchange in spring and winter were also lower under the PV arrays, explained by microclimate, soil and vegetation metrics. These data are a starting point to develop understanding of the effects of solar parks in other climates, and provide evidence to support the optimisation of solar park design and management to maximise the delivery of ecosystem services from this growing land use.
This study assessed the climate conditions inside a greenhouse in which 50% of the roof area was replaced with photovoltaic (PV) modules, describing the solar radiation distribution and the variability of temperature and humidity. The effects of shading from the PV array on crop productivity were described on tomato, also integrating the natural radiation with supplementary lighting powered by PV energy. Experiments were performed inside an east–west oriented greenhouse (total area of 960m2), where the south-oriented roofs were completely covered with multi-crystalline silicon PV modules, with a total rated power of 68kWp. The PV system reduced the availability of solar radiation inside the greenhouse by 64%, compared to the situation without PV system (2684MJm−2 on yearly basis). The solar radiation distribution followed a north–south gradient, with more solar energy on the sidewalls and decreasing towards the center of the span, except in winter, where it was similar in all plant rows. The reduction under the plastic and PV covers was respectively 46% and 82% on yearly basis. Only a 18% reduction was observed on the plant rows farthest from the PV cover of the span. The supplementary lighting, powered without exceeding the energy produced by the PV array, was not enough to affect the crop production, whose revenue was lower than the cost for heating and lighting. The distribution of the solar radiation observed is useful for choosing the most suitable crops and for designing PV greenhouses with the attitude for both energy and crop production.
|Author||Marco Cossu, Lelia Murgia, Luigi Ledda, Paola A. Deligios, Antonella Sirigu, Francesco Chessa, Antonio Pazzona|
|Citation||Marco Cossu, Lelia Murgia, Luigi Ledda, Paola A. Deligios, Antonella Sirigu, Francesco Chessa, Antonio Pazzona. 2014. Solar radiation distribution inside a greenhouse with south-oriented photovoltaic roofs and effects on crop productivity. Applied Energy. 133:89-100.|
|Topic||Agricultural Yields, Design Configurations, Energy Production, Costs and Economics, Microclimate, Greenhouse, Shading and Light Patterns|
Renewable energy could often be land constrained by the diffuse nature of renewable resources. To relax land constraints, we propose the concept of ‘aglectric’ farming, where agricultural land will be sustainably shared for food and energy co-production. While wind turbines on agricultural land are already put into practice, solar power production on agricultural land is still under research. Here, we propose photovoltaic systems that are suitable for installation on agricultural land. Adjusting the intensity, spectral distribution and duration of shading allows innovative photovoltaic systems to achieve significant power generation without potentially diminishing agricultural output. The feasibility of solar aglectric farms has been proven through shadow modelling. The proposed solar aglectric farms—used alone or in combination with regular solar parks or wind plants—could be a solution for a sustainable renewable economy that supports the ‘full Earth’ of over 10 billion people.
|Author||Caleb K. Miskin, Yiru Li, Allison Perna, Ryan G. Ellis, Elizabeth K. Grubbs, Peter Bermel, Rakesh Agrawal|
|Citation||Caleb K. Miskin, Yiru Li, Allison Perna, Ryan G. Ellis, Elizabeth K. Grubbs, Peter Bermel, Rakesh Agrawal. 2019. Sustainable co-production of food and solar power to relax land-use constraints. Nature Sustainability. 2:972–980.|
|Topic||Agricultural Yields, Design Configurations, Energy Production, Novel Solar Technologies, Technical and Market Potential, Shading and Light Patterns|
The strategic engineering of solar energy technologies—from individual rooftop modules to large solar energy power plants—can confer significant synergistic outcomes across industrial and ecological boundaries. Here, we propose techno–ecological synergy (TES), a framework for engineering mutually beneficial relationships between technological and ecological systems, as an approach to augment the sustainability of solar energy across a diverse suite of recipient environments, including land, food, water, and built-up systems. We provide a conceptual model and framework to describe 16 TESs of solar energy and characterize 20 potential techno–ecological synergistic outcomes of their use. For each solar energy TES, we also introduce metrics and illustrative assessments to demonstrate techno–ecological potential across multiple dimensions. The numerous applications of TES to solar energy technologies are unique among energy systems and represent a powerful frontier in sustainable engineering to minimize unintended consequences on nature associated with a rapid energy transition.
|Author||Rebecca R. Hernandez, Alona Armstrong, Jennifer Burney, Greer Ryan, Kara Moore-O’Leary, Ibrahima Diédhiou, Steven M. Grodsky, Leslie Saul-Gershenz, Rob Davis, Jordan Macknick, Dustin Mulvaney, Garvin A. Heath, Shane B. Easter, Madison K. Hoffacker, Michael F. Allen, Daniel M. Kammen|
|Citation||Rebecca R. Hernandez, Alona Armstrong, Jennifer Burney, Greer Ryan, Kara Moore-O’Leary, Ibrahima Diédhiou, Steven M. Grodsky, Leslie Saul-Gershenz, Rob Davis, Jordan Macknick, Dustin Mulvaney, Garvin A. Heath, Shane B. Easter, Madison K. Hoffacker, Michael F. Allen, Daniel M. Kammen. 2019. Techno–ecological synergies of solar energy for global sustainability. Nature Sustainability. 2:560–568.|
|Strategy||Animal Grazing, Apiaries, Concentrating Solar Power, Conventional Practices, Crop Production, Native/Pollinator-Friendly Vegetation|
|Topic||Best Practices, Design Configurations, Environmental Impacts, Siting, Social Issues and Perspectives|
While photovoltaic (PV) renewable energy production has surged, concerns remain about whether or not PV power plants induce a “heat island” (PVHI) effect, much like the increase in ambient temperatures relative to wildlands generates an Urban Heat Island effect in cities. Transitions to PV plants alter the way that incoming energy is reflected back to the atmosphere or absorbed, stored, and reradiated because PV plants change the albedo, vegetation, and structure of the terrain. Prior work on the PVHI has been mostly theoretical or based upon simulated models. Furthermore, past empirical work has been limited in scope to a single biome. Because there are still large uncertainties surrounding the potential for a PHVI effect, we examined the PVHI empirically with experiments that spanned three biomes. We found temperatures over a PV plant were regularly 3–4 °C warmer than wildlands at night, which is in direct contrast to other studies based on models that suggested that PV systems should decrease ambient temperatures. Deducing the underlying cause and scale of the PVHI effect and identifying mitigation strategies are key in supporting decision-making regarding PV development, particularly in semiarid landscapes, which are among the most likely for large-scale PV installations.
|Author||Greg A. Barron-Gafford, Rebecca L. Minor, Nathan A. Allen, Alex D. Cronin, Adria E. Brooks, Mitchell A. Pavao-Zuckerman|
|Citation||Greg A. Barron-Gafford, Rebecca L. Minor, Nathan A. Allen, Alex D. Cronin, Adria E. Brooks, Mitchell A. Pavao-Zuckerman. 2016. The Photovoltaic Heat Island Effect: Larger solar power plants increase local temperatures. Scientific Reports. 6:35070.|
|Strategy||Conventional Practices, Native/Pollinator-Friendly Vegetation|
|Topic||Environmental Impacts, Microclimate|
In order to meet global energy demands with clean renewable energy such as with solar photovoltaic (PV) systems, large surface areas are needed because of the relatively diffuse nature of solar energy. Much of this demand can be matched with aggressive building integrated PV and rooftop PV, but the remainder can be met with land-based PV farms. Using large tracts of land for solar farms will increase competition for land resources as food production demand and energy demand are both growing and vie for the limited land resources. This land competition is exacerbated by the increasing population. These coupled land challenges can be ameliorated using the concept of agrivoltaics or co-developing the same area of land for both solar PV power as well as for conventional agriculture. In this paper, the agrivoltaic experiments to date are reviewed and summarized. A coupled simulation model is developed for both PV production (PVSyst) and agricultural production (Simulateur mulTIdisciplinaire les Cultures Standard (STICS) crop model), to gauge the technical potential of scaling agrivoltaic systems. The results showed that the value of solar generated electricity coupled to shade-tolerant crop production created an over 30% increase in economic value from farms deploying agrivoltaic systems instead of conventional agriculture. Utilizing shade tolerant crops enables crop yield losses to be minimized and thus maintain crop price stability. In addition, this dual use of agricultural land can have a significant effect on national PV production. The results showed an increase in PV power between over 40 and 70 GW if lettuce cultivation alone is converted to agrivoltaic systems in the U.S. It is clear, further work is warranted in this area and that the outputs for different crops and geographic areas should be explored to ascertain the potential of agrivoltaic farming throughout the globe.
Agrivoltaics describes concurrent agricultural production of crops and photovoltaic generation of electricity on the same cropland. By using tinted semi‐transparent solar panels, this study introduces a novel element to transform the concept of agrivoltaics from just solar‐sharing to selective utilization of different light wavelengths. Agrivoltaic growth of basil and spinach is tested. When compared with classical agriculture, and based on the feed‐in‐tariff of the experimental location, agrivoltaic co‐generation of biomass and electricity is calculated to result in an estimated financial gross gain up to +2.5% for basil and +35% for spinach. Marketable biomass yields do not change significantly for basil, while a statistically significant loss is observed for spinach. This is accompanied by a relative increase in the protein content for both plants grown under agrivoltaic conditions. Agrivoltaics implemented with tinted solar panels improve the biomass production per unit amount of solar radiation up to 68%, with up to 63% increase in the ratio of leaf and stem biomass to root. Agrivoltaics can enrich the portfolio of farmers, mitigate risks associated with climate, and vastly enhance global photovoltaics capacity without compromising agricultural production.
|Author||Elinor P. Thompson, Emilio L. Bombelli, Simon Shubham, Hamish Watson, Aldous Everard, Vincenzo D’Ardes, Andrea Schievano, Stefano Bocchi, Nazanin Zand, Christopher J. Howe, Paolo Bombell|
|Citation||Elinor P. Thompson, Emilio L. Bombelli, Simon Shubham, Hamish Watson, Aldous Everard, Vincenzo D’Ardes, Andrea Schievano, Stefano Bocchi, Nazanin Zand, Christopher J. Howe, Paolo Bombell. 2020. Tinted Semi‐Transparent Solar Panels Allow Concurrent Production of Crops and Electricity on the Same Cropland. Advanced Energy Materials. 2001189:1-9.|
|Topic||Agricultural Yields, Energy Production, Costs and Economics, Microclimate, Novel Solar Technologies, Plant Physiology, Shading and Light Patterns|
Solar energy installations in deserts are on the rise, fueled by technological advances and policy changes. Deserts, with a combination of high solar radiation and availability of large areas unusable for crop production are ideal locations for large solar installations. However, for efficient power generation, solar infrastructures use large amounts of water for construction and operation. We investigated the water use and greenhouse gas (GHG) emissions associated with solar installations in North American deserts in comparison to agave-based biofuel production, another widely promoted potential energy source from arid systems. We determined the uncertainty in our analysis by a Monte Carlo approach that varied the most important parameters, as determined by sensitivity analysis. We considered the uncertainty in our estimates as a result of variations in the number of solar modules ha–1, module efficiency, number of agave plants ha–1, and overall sugar conversion efficiency for agave. Further, we considered the uncertainty in revenue and returns as a result of variations in the wholesale price of electricity and installation cost of solar photovoltaic (PV), wholesale price of agave ethanol, and cost of agave cultivation and ethanol processing. The life-cycle analyses show that energy outputs and GHG offsets from solar PV systems, mean energy output of 2405 GJ ha–1 year–1 (5 and 95% quantile values of 1940–2920) and mean GHG offsets of 464 Mg of CO2 equiv ha–1 year–1 (375–562), are much larger than agave, mean energy output from 206 (171–243) to 61 (50–71) GJ ha–1 year–1 and mean GHG offsets from 18 (14–22) to 4.6 (3.7–5.5) Mg of CO2 equiv ha–1 year–1, depending upon the yield scenario of agave. Importantly though, water inputs for cleaning solar panels and dust suppression are similar to amounts required for annual agave growth, suggesting the possibility of integrating the two systems to maximize the efficiency of land and water use to produce both electricity and liquid fuel. A life-cycle analysis of a hypothetical colocation indicated higher returns per m3 of water used than either system alone. Water requirements for energy production were 0.22 L MJ–1 (0.28–0.19) and 0.42 L MJ–1 (0.52–0.35) for solar PV–agave (baseline yield) and solar PV–agave (high yield), respectively. Even though colocation may not be practical in all locations, in some water-limited areas, colocated solar PV–agave systems may provide attractive economic incentives in addition to efficient land and water use.
The installation of tilting-angle solar panels above agricultural plots provides renewable energy and means of action to dampen some of the effects and hazards of climate change. When the panels are properly operated, their drop shadow reduces water consumption by the plants, as a consequence of alternating shade and sun bands with a short-term impact on the stomatal conductance and a global decrease of gas exchanges. This urged the development of a new model for crop growth and water budget, adapted here from existing literature to handle such transient conditions, characterized by short-term (infra-day) fluctuations. The main difficulty was to combine short-term fluctuations in the climatic forcings (radiation interception and rain redistribution by the panels) and long-term agronomic evaluation, hence the coexistence of several calculation time steps in model structure. All field experiments were conducted on purpose in the agrivoltaic plot of Lavalette (Montpellier, France). Specific adaptations consisted in describing the stomatal behavior of the plants for fluctuating solar radiations and varied water status, aiming at improving both the piloting of the solar panels and water management, i.e. the choice of irrigation amounts. Model simulations have been able to reproduce the expected benefits from agrivoltaic installations, for example showing that it is possible to improve land use efficiency and water productivity at once, by reducing irrigation amounts by 20%, when tolerating a decrease of 10% in yield or, alternatively, a slight extension of the cropping cycle. Agrivoltaism appears a solution for the future when facing climate change and the food and energy challenges, typically in the rural areas and the developing countries and especially if the procedure presented here proves relevant for other crops and contexts.
|Author||Y. Elamri, B. Cheviron, J.-M. Lopez, C. Dejean, G. Belaud|
|Citation||Y. Elamri, B. Cheviron, J.-M. Lopez, C. Dejean, G. Belaud. 2018. Water budget and crop modelling for agrivoltaic systems: Application to irrigated lettuces. Agricultural Water Management. 208:440-453.|
|Topic||Agricultural Yields, Design Configurations, Hydrology, Soil, Microclimate, Plant Physiology|
Global renewable electricity generation capacity has rapidly increased in the past decade. Increasing the sustainability of electricity generation and the market share of solar photovoltaics (PV) will require continued cost reductions or higher efficiencies. Wavelength‐Selective Photovoltaic Systems (WSPVs) combine luminescent solar cell technology with conventional silicon‐based PV, thereby increasing efficiency and lowering the cost of electricity generation. WSPVs absorb some of the blue and green wavelengths of the solar spectrum but transmit the remaining wavelengths that can be utilized by photosynthesis for plants growing below. WSPVs are ideal for integrating electricity generation with glasshouse production, but it is not clear how they may affect plant development and physiological processes. The effects of tomato photosynthesis under WSPVs showed a small decrease in water use, whereas there were minimal effects on the number and fresh weight of fruit for a number of commercial species. Although more research is required on the impacts of WSPVs, they are a promising technology for greater integration of distributed electricity generation with food production operations, for reducing water loss in crops grown in controlled environments, as building‐integrated solar facilities, or as alternatives to high‐impact PV for energy generation over agricultural or natural ecosystems.
|Author||Michael E. Loik, Sue A. Carter, Glenn Alers, Catherine E. Wade, David Shugar, Carley Corrado, Devin Jokerst, Carol Kitayama|
|Citation||Michael E. Loik, Sue A. Carter, Glenn Alers, Catherine E. Wade, David Shugar, Carley Corrado, Devin Jokerst, Carol Kitayama. 2017. Wavelength‐Selective Solar Photovoltaic Systems: Powering Greenhouses for Plant Growth at the Food‐Energy‐Water Nexus. Earth's Future. 5(10):1044-1053.|
|Topic||Agricultural Yields, Energy Production, Hydrology, Microclimate, Greenhouse, Novel Solar Technologies, Plant Physiology, Shading and Light Patterns|
Large areas of public land are currently being permitted or evaluated for utility-scale solar energy development (USSED) in the southwestern United States, including areas with high biodiversity and protected species. However, peer-reviewed studies of the effects of USSED on wildlife are lacking. The potential effects of the construction and the eventual decommissioning of solar energy facilities include the direct mortality of wildlife; environmental impacts of fugitive dust and dust suppressants; destruction and modification of habitat, including the impacts of roads; and off-site impacts related to construction material acquisition, processing, and transportation. The potential effects of the operation and maintenance of the facilities include habitat fragmentation and barriers to gene flow, increased noise, electromagnetic field generation, microclimate alteration, pollution, water consumption, and fire. Facility design effects, the efficacy of site-selection criteria, and the cumulative effects of USSED on regional wildlife populations are unknown. Currently available peer-reviewed data are insufficient to allow a rigorous assessment of the impact of USSED on wildlife.
|Author||Jeffrey E. Lovich, Joshua R. Ennen|
|Citation||Jeffrey E. Lovich, Joshua R. Ennen. 2011. Wildlife Conservation and Solar Energy Development in the Desert Southwest, United States. BioScience. 61(12):982–992.|
|Jurisdiction||State: Arizona, California, Colorado, Nevada, New Mexico, Utah|
|Topic||Environmental Impacts, Hydrology, Operations and Maintenance, Siting, Soil, Microclimate|
Abstract Global energy demand is increasing as greenhouse gas driven climate change progresses, making renewable energy sources critical to future sustainable power provision. Land-based wind and solar electricity generation technologies are rapidly expanding, yet our understanding of their operational effects on biological carbon cycling in hosting ecosystems is limited. Wind turbines and photovoltaic panels can significantly change local ground-level climate by a magnitude that could affect the fundamental plant?soil processes that govern carbon dynamics. We believe that understanding the possible effects of changes in ground-level microclimates on these phenomena is crucial to reducing uncertainty of the true renewable energy carbon cost and to maximize beneficial effects. In this Opinions article, we examine the potential for the microclimatic effects of these land-based renewable energy sources to alter plant?soil carbon cycling, hypothesize likely effects and identify critical knowledge gaps for future carbon research.