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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Microclimate modelling for agrivoltaic systems

Zainali, Sebastian January 2024 (has links)
Increasing global electricity consumption and population growth have resulted in conflicts between renewable energy sources, such as bioenergy and ground-mounted photovoltaic systems, owing to the limited availability of suitable land caused by competing land uses. This challenge is further compounded by the intertwined relationship between energy and agri-food systems, where approximately 30% of global energy is consumed. In addition, considering that agricultural irrigation accounts for 70% of water use worldwide, its impact on both land and water resources becomes a critical concern. Agrivoltaics offers a potential solution to this land use conflict. However, a knowledge gap remains regarding the impact of integrating these techniques on microclimatic conditions. Addressing this gap is crucial because these conditions directly affect the growth and development of crops, as well as the efficiency of energy yields in photovoltaic panels. Experimental facilities offer valuable insights tailored to specific locations and system designs. Although they provide an in-depth understanding of a particular location, the extrapolation of this information to different locations or alternative systems may be limited. Therefore, the broader applicability of these insights to diverse settings or alternative systems remains unclear. In this thesis, a modelling procedure was developed to evaluate the photosynthetically active radiation reaching crops in typical agrivoltaic configurations across three diverse geographical locations in Europe. This is essential for understanding how solar panel shading affects the incoming photosynthetically active radiation required for crop photosynthesis. Furthermore, computational fluid dynamics were employed to model and assess the microclimate of an experimental agrivoltaic system. The developed model revealed significant variations in photosynthetically active radiation distribution across different agrivoltaic systems and locations, emphasising the need for tailored designs for optimal energy yield and crop productivity. Computational fluid dynamics analysis demonstrated its effectiveness in evaluating microclimatic parameters such as air and soil temperature, wind speed, and solar irradiance within agrivoltaic systems, providing valuable insights for system optimisation. By bridging a knowledge gap, this thesis contributes to the understanding of the modelling and simulation of agrivoltaic system microclimates, thereby facilitating the sustainable coexistence of renewable electricity conversion and agriculture.
2

EVALUATION OF LAND, SOIL, WATER, AND VEGETATION-RELATED ECOSYSTEM SERVICES AND TRADEOFFS AT UTILITY-SCALE SOLAR PHOTOVOLTAIC FACILITIES

Choi, Chong Seok, 0000-0002-6860-2038 05 1900 (has links)
Solar photovoltaics are a low-emission electricity source, but utility-scale development of ground-mounted PV may displace natural or agricultural land and compromise the land’s ability to provide ecosystem services. Co-locating solar photovoltaics with vegetation (sometimes referred to as “agrivoltaics”) could provide a sustainable solution to meet growing food and energy demands while minimizing the land-use impacts of solar energy. Pilot-scale experiments and modeling studies have shown potential for microclimatic alterations by the solar photovoltaics (PV) and the soil-vegetation components of a co-located system to benefit each other. One predicted co-benefit is cooling of PV modules caused by diversion of sensible heat to latent heat for evapotranspiration in the understory vegetation during the growing season. Field experiments that validate the theorized co-benefits within a utility-scale co-located system are less common. Since a large percentage of current and future land use conversions for utility-scale solar energy developments are estimated to occur on farmlands, validation of co-benefits in utility-scale co-located systems are critical for determining the outcome of co-location in a wide range of physical conditions and optimizing the system design for the environmental co-benefits. In the first study of its kind and scale, three years (2019 – 2021) of microclimate and soil data at three vegetated utility-scale solar plants in Minnesota were tied to the power output data from the corresponding period to examine the influence of ground cover on the PV performance and that of the arrays on the underlying soil and vegetation. Soil moisture, soil temperature, air temperature, relative humidity, wind direction/speed were recorded at a 15-minute interval at three treatments: PV arrays with a vegetated ground cover (“veg PV”), PV arrays with a bare ground cover (“bare PV”), and a nearby open space with the same vegetation as that in veg PV (control). Solar irradiance and cumulative precipitation were also recorded in the control. While air temperature and relative humidity were not significantly different between the veg PV and the bare PV, soil moisture was lowest in the bare PV treatment and comparable between the veg PV and the control. Soil moisture also varied spatially along the transect perpendicular to the array, though the spatial distribution was not consistent between the treatments and different facilities. Soil temperature was the lowest in the veg PV and the highest in the control, implying that the partial shade from the solar array keeps the underlying soils cooler. Cooler soil temperature in PV arrays could be a buffer for plants during periods of drought, which implies that co-located systems could be implemented in ecosystem restoration projects for climate resilience. In addition to the microclimate variables, panel temperature was also recorded at veg PV and bare PV treatments and electricity generation data from the corresponding treatments during the study period was provided by the operators of the facilities. Neither vegetation-driven panel cooling nor the increased power output was observed in the veg PV: the bare PV had higher output and panel temperatures than the veg PV in the early mornings, which may imply that the observed difference in output may be due to shading of the panels in the veg PV treatment by the co-located vegetation. The differential of total daily production (bare PV – veg PV) was positive on most days, though the mode in a frequency distribution of the differential was centered around a very small positive value. The lack of panel-cooling in the veg PV was determined to be due to the short rainfall interval (1-2 days) during the study period. Because of the frequent rainfalls, evaporation in the bare PV treatment and evapotranspiration process in the veg PV treatment remained in an energy-limited stage, and the water would evaporate more rapidly from the bare soil that is more exposed to sunlight and wind. In a drier environment with infrequent rainfalls, evaporation and evapotranspiration would be moisture-limited most of the times, and plants may be able to transpire water from deeper in the soil over a longer period of time to cool the overlying panels, given enough irrigation. The lack of panel cooling in our field sites implies that such environmental co-benefits are likely to be climate dependent, which indicates the need for further study of the influence of the vegetation on the PV operation and vice-versa at large-scale solar facilities in varying climate zones. Soil samples were also collected for grain size analysis using laser diffraction and nutrient analysis using standard combustion methods. In the sandy soils at the Chisago facility, the bare PV treatment had significantly less clay portion than the veg PV treatment and the control. On the other hand, the clay percentages did not significantly differ among the three treatments in the other two facilities with higher background clay contents (Atwater and Eastwood). The loss in total carbon, nitrogen, and soil cations was also the most pronounced in the bare PV in a facility with the sandy soil. Maintenance of vegetation or re-vegetation while minimizing land grading may protect the soil’s ability to store carbon and nutrients, and that effect may be magnified in coarse-textured soils or ones whose carbon and nutrient storage capacity is otherwise compromised. Overall, the field investigation found that the occurrence of some of the environmental co-benefits of co-locating PV with vegetation depended on the climate and soil, prompting a need for case-by-case consideration of these variables to identify which of the co-benefits will be achievable. Extensive solar PV development to meet energy demand and decarbonize the energy grid will significantly impact the landscape. Co-location offers an opportunity to mitigate the potential negative impacts of utility-scale solar energy, while still meeting sustainable development goals. A system dynamics model is developed to compare the regional land occupation, water usage, carbon emissions, and change in soil carbon storage resulting from solar development using two different development strategies: traditional, in which the land is graded and vegetation is removed, and co-location, in which land grading is minimized and the soil is re-vegetated with native vegetation. The model is applied in two water-sensitive semi-arid regions with high technical potential for solar energy where agriculture is an important element of the local economy. First, Rajasthan, India is undergoing rapid expansion of solar PV to address the growing energy demand while meeting sustainable energy development goals in a developing economy. The results show that at the current growth rate of solar energy in Rajasthan, solar energy will grow to more than 500 GW by 2070 and will occupy a land area equivalent to 20% to 95% of the unused land suitable for solar. Second, the Central Valley of California has a mature power system in a mature economy seeking to decarbonize. The results show that the overall capacity of California’s solar energy in 2070 will be less than a fifth of Rajasthan’s and occupy at most 10% of California’s unused land suitable for solar. Consequently, soil carbon loss due to future solar capacity additions under conventional development strategy will be similarly smaller in California than in Rajasthan. Together, the results show that the opportunity for the mitigation of the negative impacts of energy development may be greater in younger economies with a developing grid network. / Geoscience
3

Agrivoltaic Implementation in Greenhouses : A Techno-Economic Analysis of Agrivoltaic Installations for Greenhouses in Sweden

Gauffin, Henrik January 2022 (has links)
Due to the growing population and climate change, the world will see an increase in demand for food, freshwater and renewable energy supply. Agrivoltaics has the possibility to address all these problems, by producing food and renewable energy but also by reducing water usage in agriculture. This thesis aims to study if agrivoltaics including storage has the potential to enable sustainable greenhouses in Stockholm, Sweden by trying to create a near net zero energy consumption for greenhouses with Agrivoltaics (AV) implemented. Furthermore a techno-economic assessment will be made for the AV-systems where Key Performance Indicator (KPI)’s are compared to economic parameters. The selected KPI’s were a near net zero energy consumption and irradiance underneath the Photovoltaics (PV) technology. The selected PV-technology was standard PV-modules, Semi-Transparent Module (STM) and Organic Solar Cell (OSC) PV. These technologies were paired with li-ion batteries between 0-100 kWh and simulated in the software System Advisor Model (SAM) over a 25 year period. The AV system was applied to two load profiles, one for indoor plants and one for tomatoes. The economic parameters calculated was Net Present Value (NPV), Net Capital Cost (NCC), and Levelised Cost of Electricity (LCOE).  The results showed that the system is efficient in summertime where the PV reached maximum capacity in summer and the battery works as a complement. In wintertime, the AV-system is not very efficient and most of the electricity comes from the grid. It was not possible to create a near net zero energy consumption including storage in Stockholm Sweden. The irradiance beneath the panels were at a maximum for OSC, it was slightly reduced for the STM, and below 50% for the standard PV-module, depending on the size of the AV-system. Depending on the shade tolerance of the plant, the PV-technology should be selected.
4

Modélisation et optimisation de la croissance de la laitue dans un système agrivoltaïque dynamique / Modeling and optimization of lettuce growth in dynamic agrivoltaic systems

Valle, Benoît 26 June 2017 (has links)
L’agrivoltaïque, combinaison de panneaux photovoltaïques et d’une culture sur le même sol, a été proposé en 1982 comme solution au conflit d’usage des sols. Lancé en 2010 à Montpellier, le concept associant panneaux fixes et diverses cultures a fait la preuve d’une productivité combinée de la parcelle améliorée grâce, notamment, à l’acclimatation de la culture à l’ombre. Dans cette thèse, les panneaux fixes ont été échangés par des panneaux orientables au cours de la journée. L’objectif était d’optimiser l’orientation des panneaux pour maximiser la productivité combinée de la parcelle sans pénaliser la culture. Pour cela, la croissance et le développement de laitues ont été analysés en conditions contrôlées et en plein champ sous différentes modalités d’ombrage par panneaux fixes ou mobiles. Les panneaux mobiles ont permis d’améliorer la productivité combinée de la parcelle par rapport à des panneaux fixes, avec un maintien de la production agricole dans certaines conditions. Une approche écophysiologique basée sur le développement de la plante, sa capacité à intercepter et convertir le rayonnement en biomasse, a révélé que les modalités d’ombrage avaient peu d’impact sur la mise en place de la surface foliaire malgré des différences de biomasse accumulée en rapport avec le rayonnement transmis à la plante. Des modifications du développement foliaire ont conduit à une meilleure utilisation du rayonnement transmis lorsque celui-ci était réduit. Ce travail a débouché sur une modélisation de l’impact de l’orientation des panneaux sur la biomasse des laitues permettant d’optimiser le pilotage des panneaux en fonction du scénario climatique et des objectifs de productions. / Agrivoltaic systems, combining solar panels and crops on the same land were proposed in the early 1980’s as a solution to solve land use conflict. Introduced in 2010 in Montpellier, the concept has proven itself associating fixed panels to multiple food crops. Total land productivity was improved, thanks to plant acclimation to shade. In this thesis, fixed panels were replaced with mobile panels, adjustable along the day. The aim of this work was to optimize solar panel orientations to maximise total land productivity without threatening the crop culture. Growth and development of lettuces were analysed in controlled conditions and in the field under several shading conditions by fixed or mobile panels. Total land productivity was improved with mobile panels in comparison with fixed panels, maintaining lettuce yield under certain conditions. Through an ecophysiological approach based on plant development and its ability to intercept and convert light into biomass, the different shading conditions were shown to have a small impact in the plant leaf area dynamic despite large differences in accumulated dry mass associated with transmitted radiation at the plant level. This was due to differences in leaf development resulted in higher use of the transmitted radiation when it was reduced. This study proposed a modelling approach of the incidence of panel orientations on lettuce dry mass at harvest. The model allows an optimisation of solar panels controlling as a function of climate scenario and crop and electricity production objectives.
5

Experimental Demonstration of Agrivoltaic Systems via Multi-Scale Design and Characterization

Elizabeth Kathleen Grubbs (12232037) 20 April 2022 (has links)
As the global population approaches 11 billion people, demands for sustainable food, energy, and water (FEW) are approaching unprecedented levels. Current technology places sustainable FEW production methods in direct competition with one another for global surface area, such as land area for agriculture versus photovoltaic farms. This is because current installation methods for solar modules create deep shading that suppresses plant growth. The field of agrivoltaics (AgPV) addresses this issue directly by optimizing coproduction strategies for FEW and developing systems where competition is reduced; however, previous work has seen reductions in agricultural output. AgPV, where module architecture is also modified and agricultural output is minimally impacted, requires novel multi-level experimental design and characterization. In my proposed thesis, I will address the following two aspects of the project: (1) a farm-level experimental analysis of existing PV and (2) a device-level analysis of new and emerging PV material candidates. To establish the plausibility of this work, I designed and implemented an agrivoltaic system with two treatments that was successfully farmed this year. In my thesis, I will demonstrate a fully characterized utility scale AgPV array through several steps. First, I will validate the prior simulation work on the constructed AgPV array. Then I will experimentally correlate crop growth underneath the AgPV experiment. Next, the effects of the shadowing from the array on crop growth will be quantified. I will optimize the tracking algorithm for the array to maximize crop growth during the summer and power production during other seasons. Finally, I will investigate a platform for evaluation of novel PV materials and devices tailored for AgPV systems using Photoluminescence Excitation Spectroscopy (PLE) where I redesigned, constructed, and validated a new experimental design.
6

Possible implementations of agrivoltaics in Sweden : With focus on solar irradiation and electricity production

Suuronen, Jennifer January 2022 (has links)
With a need for rapid growth of renewable energy sources like photovoltaics, there will also be a competition of land. Agriculture and solar energy share the same optimum conditions of land to produce. But with a combination of the two on the same surface, a concept called agrivoltaic, that issue can be solved. This projects has investigated the possibilities of implementing an agrivoltaic system in Sweden in the near future with a focus on solar irradiation, energy production and crop selection. The decrease in solar irradiation under the panels was simulated because it is an important parameter in making these kinds of systems profitable from a crop and energy perspective. The annual energy production and energy yield was also simulated for various system designs for a comparison between the two important parameters of an agrivoltaic system.  One solar fence system, a single axis tracker system and an integrated PV system was chosen for the simulations. In general, all results of agrivoltaics is location dependent due to important differences in solar irradiance and climate. The solar fence system had the best results regarding the solar irradiance, with a decrease in the range of 3-5% and 20-28 % depending on the design. Single axis trackers had a minimum 3-8 % and maximum 40-59 % and integrated PV had a minimum 42-60% and maximum 50-75 % reduction. When the annual energy was compared with a row spacing of 12 m, the solar fence has an annual energy of 1738 kWh and single axis trackers got 2812 kWh. The results indicate that depending on what is most important for the system, the recommendations are different. If energy is more important, then the single axis tracker system can be a good fit but if it is solar irradiance, the solar fence is better. Both systems should be suitable for shade tolerant crops but if experimenting with others such as field bean and barley, the solar fence is more appropriate. The results for the integrated panels designs indicates that these designs are not a good first fit for Sweden since the reduction is greater than 50 % for most designs. Since there is only one agrivoltaic system in Sweden with results on one type of crop, there is a need for more systems with different designs and crops to be able to tell the real potential of agrivoltaics is Sweden. / För att nå nationella mål om förnybara energikällor i den svenska energimixen behövs en snabbtillväxt. Regeringen har efterfrågat en strategi för att öka de förnyelsebara energikällorna framtill 2040. Det skulle innebära en ökning av solenergin och därmed också öka konkurrensen avmarkytor. Agrivoltaics är ett koncept som kombinerar solceller och jordbruk på samma yta ochdärmed är konkurrensen av markyta inte ett problem vid implementering av sådana projekt.Detta projekt har undersökt möjligheten att implementera ett agrivoltaic system i Sverigeeftersom det har blivit ett hett ämne inom solcellsindustrin. Syftet med denna studie är att tafram ett underlag för Svea Solar som kan vara till hjälp för att avgöra vilket agrivoltaic systemsom är bäst för en första implementering i Sverige beroende på solinstrålning, energiproduktionoch val av grödor. Detta inkluderade att föra en förstudie av olika befintliga agrivoltaic systemoch intervjua tidigare jordbrukskunder till Svea Solar. Den största oron bland bönderna var hurett sådant system skulle påverka skörden, energiproduktionen och därmed ekonomin. Detta varanledningen till att solinstrålning valdes som en viktig parameter att simulera. Solceller ochfotosyntesen i växter behöver solinstrålning för att producera och därför är det en viktig faktori utformningen av ett agrivoltaic system.Solinstrålningen under utvalda system och solpaneler simulerades. Energiutbytet simuleradesockså för att kunna jämföra de båda viktiga faktorerna av ett agrivoltaic system. Ett systemmed vertikala paneler (Solar fence), ett enaxlat spårsystem (Single axis tracker system) och ettintegrerat system valdes för simuleringarna. Ett integrerat system definieras genom att en delmaterial i ett system/objekt ersätts med ett annat, i detta fall solceller. Till exempel plasten somanvända i odlingstunnlar för produktion av bland annat bär.Generellt är resultaten för agrivoltaic system plastsberoende på grund av viktiga skillnader isolinstrålning och klimat. Resultaten visade hur mycket solinstrålningen och därmed också denårliga energin minskade beroende på systemdesign. De vertikala panelerna visade på bästresultat vad gäller solinstrålningen med en minsta minskning på 3-5 % och som mest 20-28 %under hela dagen beroende på design. Enaxlade spårare hade minst 3-8 % och som mest 40-59% och integrerade systemet hade minst 42-60 % och mest 50-75 % minskning avsolinstrålningen. När den årliga energiproduktionen jämfördes med ett fast radavstånd på 12 mhade de vertikala panelerna ett årligt resultat på 1738 kWh i jämförelse med det enaxladesystemet som producerade 2812 kWh.Resultaten, från simuleringen av solinstrålning, indikerar att ett vertikalt system är bäst lämpatför att experimentera med olika grödor, skuggtåliga men också mer känsliga grödor såsom kornoch åkerböna. Enaxliga spårare är ett bra alternativ med skuggtåliga grödor om elproduktionenär den viktigaste delen av systemet, då den gav goda resultat i energisimuleringen. Resultatenför de integrerade systemen indikerar att dessa konstruktioner inte passar lika bra för Sverigeeftersom minskningen av solinstrålning är markant större.
7

Tracking Optimization in Agrivoltaic Systems : A Comparative Study for Apple Orchards

Bruno, Maddalena January 2023 (has links)
Agrivoltaic (APV) systems, based on the co-location of solar panels and crops, are an innovative solution to land-use conflicts that often arise between agriculture and energy production. Their optimal functioning starts with efficient management and sharing of light between solar panels and underlying plants. This is where tracking systems come into play, as they offer the flexibility needed to strike a balance between energy production and crop growth. This thesis presents several tracking optimization techniques that focus on the availability and distribution of light. To simulate and analyze the performance of these strategies, a simulation model was created, with reference to a Fraunhofer ISE research project in Bavendorf, Germany where semi-transparent solar panels are installed over an apple orchard. The chosen developmental environment was Simtool, a Fraunhofer Python package based on the ray-tracing tool Radiance. Considering the computational cost of the simulation, a Bayesian black-box optimization algorithm was leveraged to relieve the latter from such a computational burden. For the first scenario, the goal was to maximise the radiation reaching solar panels. The algorithm developed, Diffuse-Track Optimization, proved particularly effective during overcast days, allowing daily energy gains of up to 9%. Plants were prioritized in the second scenario, Trees-Track Optimization with the goal of minimising their shading rates, which were seen to fall below 10% despite the presence of the tracking system. Lastly, a compromise between the two objectives was achieved in the final scenario through an overall optimization approach, called APV-Track Optimization. By assigning equal importance to the irradiation reaching trees and that which reaches photovoltaic panels, shading rates of less than 40% can be guaranteed throughout the year, with a reduction of the electrical yield by only 8% compared to backtracking conditions.  The study showcased the potential of the proposed methodology, representing a good starting point to develop holistic optimisations methods that are still lacking in the literature. Future developments will reduce runtime costs, integrate weather forecasts and validate results by means of accurate field measurements. / Agrivoltaiska system (APV), som baseras på samlokalisering av solpaneler och grödor, är en innovativ lösning på de markanvändningskonflikter som ofta uppstår mellan jordbruk och energiproduktion. För att de ska fungera optimalt krävs en effektiv hantering och fördelning av ljuset mellan solpaneler och underliggande växter. Det är här spårningssystem kommer in i bilden, eftersom de erbjuder den flexibilitet som behövs för att hitta en balans mellan energiproduktion och odling av grödor. I denna avhandling presenteras flera optimeringstekniker för spårningssystem som fokuserar på tillgänglighet och fördelning av ljus. För att simulera och analysera hur dessa strategier fungerar skapades en simuleringsmodell med referens till ett forskningsprojekt vid Fraunhofer ISE i Bavendorf, Tyskland, där halvtransparenta solpaneler installerades över en äppelträdgård. Den valda utvecklingsmiljön var Simtool, ett Fraunhofer Python-paket baserat på strålspårningsverktyget Radiance. Med tanke på simuleringens beräkningskostnad användes en Bayesiansk black-box-optimeringsalgoritm för att avlasta den senare från en sådan beräkningsbörda. I det första scenariot var målet att maximera den strålning som nådde solpanelerna. Den utvecklade algoritmen, Diffuse-Track Optimization, visade sig vara särskilt effektiv under mulna dagar och möjliggjorde dagliga energivinster på upp till 9%. Växter prioriterades i det andra scenariot, Trees-Track Optimization, med målet att minimera deras skuggningsgrad, som sjönk under 10% trots närvaron av spårningssystemet. Slutligen uppnåddes en kompromiss mellan de två målen i det slutliga scenariot genomen övergripande optimeringsmetod, kallad APV-Track Optimization. Genom att lägga lika stor vikt vid den strålning som når träden och den som når solcellspanelerna kan en skuggningsgrad på mindre än 40% garanteras under hela året, med en minskning av elutbytet med endast 8% jämfört med förhållanden med backtracking.  Studien visade potentialen hos den föreslagna metoden och utgör en bra utgångspunkt för att utveckla holistiska optimeringsmetoder som fortfarande saknas i litteraturen. Framtida utveckling kommer att minska drifttidskostnaderna, integrera väderprognoser och validera resultaten med hjälp av noggranna fältmätningar.
8

Comparative study of albedo and Ndvi. : Based on a vertical Agrivoltaic system and a reference control plot.

Aryal, Prasamsa January 2024 (has links)
Agrivoltaic system combines solar energy and agriculture which is an effective way to utilize the lands full potential. Crops can be grown between vertical panels or under tilted panels among other designs. Combining solar panels and agriculture leads to optimization of space. This degree project evaluates a comparison of several parameters measured both in a vertical agrivoltaic system and a reference control plot located in Kärrbo Prästgård, Västerås, Sweden. Specifically, the correlation between the ground albedo and normalized difference vegetation index (NDVI) under the two treatments are investigated. Correlations between the albedo and the NDVI against different weather parameters are also explored. Linear regression models are developed separately for the albedo and NDVI with the most correlated parameters. In addition, because the albedo in the reference is not the same as the albedo in the agrivoltaic system, a linear regression model linking the albedo of the agrivoltaic system, and the albedo of the reference system is further developed. With this latter model, power production from the vertical agrivoltaic system is simulated under different albedo considerations: using measured albedo from the agrivoltaic system, using predicted albedo from the linear regression model, and using measured albedo from the reference system. These power estimations are then compared to the real power production from the agrivoltaic system. The study employs MATLAB for data analysis, models development and power production simulations.   The study compared the correlation between ground albedo and NDVI in an agrivoltaic system and a control plot. The albedo model revealed that the reference system could explain 87% of the albedo variance in the agrivoltaic system, but the NDVI model showed that the reference system could only account for 39.6% of the variation in the agrivoltaic system. Furthermore, for the power production comparison, using the actual measured albedo in the agrivoltaic showed the most accurate power, employing predicted albedo through the linear regression model showed the second highest and using the albedo measured in the reference showed the least accurate.
9

COMBINED LAND USE OF SOLAR INFRASTRUCTURE AND AGRICULTURE FOR SOCIOECONOMIC AND ENVIRONMENTAL CO-BENEFITS IN THE TROPICS

Choi, Chong Seok Seok January 2019 (has links)
Solar photovoltaic (PV) generation has been gaining popularity as low carbon energy technology in the face of the global climate change. However, conventional utility-scale PV requires large swaths of land to be occupied for decades which prevents the land from producing food or performing vital ecosystem services. Co-location of PV with crop cultivation is an emerging strategy for mitigating the land use of PV. In order to optimize this strategy, the impact of the plant growth-related soil properties need to be quantified. To this end, the first portion of the thesis investigated the impacts on the soil properties in a re-vegetated solar PV facility in Boulder, Colorado, which was the oldest vegetation-PV co-location site in the world. The second portion of the thesis uses a life cycle analysis (LCA) approach to test the feasibility of co-location of model crop cultivation and solar PV electricity generation in rural Indonesia, and it is the first study to use the LCA study of the co-located solar in the tropics. The first approach revealed that the soil hydrology, grain size distribution, and total carbon and nitrogen are significantly altered from their original state by the construction and presence of photovoltaic arrays, and that those properties had not been restored to their pre-construction levels despite the fact that ten years had passed since re-vegetation of the PV array. The persistence of the altered soil properties meant that the designs regarding re-vegetation or co-location of PV with crops would have to be considered at the beginning of the construction of the PV to minimize the impact on the soil and the existing vegetation. Furthermore, soil moisture was the highest in the soil underneath the western edge of the PV panels, where the western tilt of the PV panel had concentrated the rainfall. The heterogeneity in soil hydrology created by the panels could be manipulated to benefit the growth of vegetation within the PV array. The LCA approach revealed that a hectare of PV arrays with full module density would carbon offsets against diesel electricity generation and the grid, and that the annual supply of electricity from the PV could satisfy the demand of a typical rural Indonesian village several times over. However, the high capital expenditure of solar mean that co-location with full PV module density would not be economically feasible, even with the income stream from the co-located crop cultivation. In order to reduce the capital expenditure, the PV module density for co-location was reduced to half. The combination of reduced capital expenditure and the income stream from the crop made the co-located land use significantly less costly. Additionally, the rural electrification would be able to provide secondary socioeconomic benefits such as avoidance of health costs through operation of public health infrastructures, increased standard of living, and secondary income opportunities from processing of raw materials. However, better subsidies for renewables, specialized loan structures for small-scale renewable systems, and a culture of co-operation between small landholders would need to be implemented before the co-located system becomes affordable to the inhabitants in rural Indonesian villages. / Geology
10

Solar Irradiance Assessment in Agrivoltaic Systems : Understanding Photosynthetically Active Radiation Separation Models and Dynamic Crop Albedo Effect in Agrivoltaic Systems Modelling

Ma Lu, Silvia January 2024 (has links)
Agrivoltaics, also referred as agrivoltaic systems, present an appealing solution, owing to its dual land use and integrated food-energy system, for the shift to renewable energy. However, it raises concerns about the complex synergies and trade-offs between crop growth and solar photovoltaic panels. Crops grown under open-field traditional agriculture receive uniformly distributed Sun irradiance, whereas agrivoltaics introduces variable shadowing, which interferes with the homogeneity of light collected by crops.  Agrivoltaics emphasises the significance of the diffuse irradiance component during shading conditions when direct irradiance is blocked by solar panels. Decomposition models are essential for estimating the diffuse light component from the global one. This thesis conducts a benchmarking investigation of state-of-the-art solar irradiance decomposition models to identify the most suitable ones for decomposing photosynthetically active radiation in specific Swedish sites. The results lead to a novel separation model that outperforms the top models revealed in the benchmarking analysis. Various scenarios common in agrivoltaic sites are used to test the applicability of the model and guide model selection based on available data.  In agrivoltaic systems, where solar panels disrupt incoming sunlight to crops, the crop reflectivity or albedo influences solar panels, particularly those with bifacial solar cells. This thesis further investigates how ground-reflected irradiance components affect the front and rear sides of bifacial system designs under varied ground albedo circumstances. Using Agri-OptiCE®, this research examines how albedo data quality affects bifacial systems. The findings contribute to improve the precision of plane-of-array irradiance and power output estimations, hence aiding the practical implementation of agrivoltaic systems across the globe.

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