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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.
21

Modelling and Assessment of Biomass-PV Tradeoff within the Framework of the Food-Energy-Water Nexus

Bao, Keyu 03 May 2023 (has links)
Food, water and energy are three essential resources for human well-being, poverty reduction and sustainable development. These resources are very much linked to one another, meaning that the actions in any one particular area often can have effects in one or both of the other areas. At the same time, an economy's shift towards climate neutrality requires a massive expansion of energy production from renewable sources. Among these ground-mounted photovoltaic (PV) and biomass will be expanded massively to meet the clean energy generation goal, simultaneously influence regional water and food availability and supply security. It is crucial to understand Food-Water-Energy Nexus (FWE) nexus during the energy transition. However, current studies have limitation both methodically (qualitative assessments) and spatially (aggregated data on a national level is more available). Firstly, a consistent share input data set in geographical format was created with the resolution of building/field. An energy simulation platform (SimStadt) was then extended with new workflows on biomass potential, ground-mounted PV potential, food demand/potential, and urban water demand. Combining with existing workflows on urban building heating/electricity demand and roof PV potential, the dissertation created a complete simulation environmental covering most-relating FWE topics in energy transition with consistent input and output structures at a fine resolution. Secondly, the most representative inter-linkage between ground-mounted PV and biomass on hinterland is investigated in details with the new tools. The output data of each field from ground-mounted PV and biomass workflows are linked and ranked according to the scenarios emphasizing PV yield, feasibility, profit, or biomass. The assessment and scenarios are applied at three representative German counties with distinguished land-use structures and geometries as case studies. Results show that current policies does not guarantee the technically efficient allocation of fields. The optimal technical strategy is to follow the individual market profit drive, which is very likely, at the same time for the social good, to achieve high PV yields with limited biomass losses and more significant crop water-saving effects. The local food, water, and energy demands are also included as a metric for resource allocation on the potential side. Besides focusing on the biomass-PV tradeoff simulation and analysis, pioneer works have also been done to test the transferability of the method in cases outside Germany, and the complement of urban solid waste to agricultural biomass is explored to achieve energy autarky.
22

A GIS-Based Simulation Method for Regional Food Potential and Demand

Bao, Keyu, Padsala, Rushikesh, Coors, Volker, Thrän, Daniela, Schröter, Bastian 05 May 2023 (has links)
A quantitative assessment of food-water-energy interactions is important to assess pathways and scenarios towards a holistically sustainable regional development. While a range of tools and methods exist that assess energetic demands and potentials on a regional scale, the same is not true for assessments of regional food demand and potential. This work introduces a new food simulation workflow to address local food potential and demand at the regional level, by extending an existing regional energy-water simulation platform. The goal of this work is to develop a GIS-based bottom-up approach to simulate regional food demand that can be linked to similarly GIS-based workflows assessing regional water demands and energetic demands and potentials. This allows us to study food-water-energy issues on a local scale. For this, a CityGML land use data model is extended with a feed and animal potential raster map as well as a soil type map to serve as the main inputs. The workflow simulates: (1) the vegetal and animal product food potentials by taking climate, crop type, soil type, organic farming, and food waste parameters into account; (2) the food demand of vegetal and animal products influenced by population change, body weight, age, human development index, and other indicators. The method is tested and validated in three German counties with various land use coverages. The results show that restricting land used exclusively for energy crop production is the most effective way to increase annual food production potential. Climate change by 2050 is expected to result in annual biomass yield changes between −4% and 2% depending on the region. The amount of animal product consumption is expected to rise by 16% by 2050, while 4% fewer vegetal products are excepted to be consumed.
23

The Water-Energy Nexus: a bottom-up approach for basin-wide management

Escrivà Bou, Àlvar 21 December 2016 (has links)
Tesis por compendio / [EN] First chapter uses California's drought to identify the economic threats of water scarcity on food, energy and environmental systems as a way to introduce the multiple interactions between these resources. The second part of this first chapter introduces the focus of the dissertation, the water-energy nexus, presents a literature review identifying gaps, states the main and specific research objectives and the research questions, explains the research approach, and describes the organization of the dissertation. Second chapter develops an end-use model for water use and related energy and carbon footprint using probability distributions for parameters affecting water consumption in 10 local water utilities in California. Statewide single-family water-related CO2 emissions are 2% of overall per capita emissions, and locally variability is presented. The impact of several common conservation strategies on household water and energy use are assessed simulating different scenarios. Based on the this model, Chapter 3 introduces a probabilistic two-stage optimization model considering technical and behavioral decision variables to obtain the most eco-nomical strategies to minimize household water and water-related energy bills and costs given both water and energy price shocks. Results can provide an upper bound of household savings for customers with well-behaved preferences, and show greater adoption rates to reduce energy intensive appliances when energy is accounted, result-ing in an overall 24% reduction in indoor water use that represents a 30 percent reduc-tion in water-related energy use and a 53 percent reduction in household water-related CO2 emissions. To complete the urban water cycle, Chapter 4 develops first an hourly model of urban water uses by customer category including water-related energy consumption and next I calibrate a model of the energy used in water supply, treatment, pumping and wastewater treatment by the utility, using real data from East Bay Municipal Utility District in California. Hourly costs of energy for the water and energy utilities are assessed and GHG emissions for the entire water cycle estimated. Results show that water end-uses account for almost 95% of all water-related energy use, but the 5% managed by the utility is still worth over $12 million annually. Several simulations analyze the potential benefits for water demand management actions. The total carbon footprint per capita of the urban water cycle is 405 kg CO2/year representing 4.4% of the total GHG emissions per capita in California. Accounting for the results obtained in Chapters 2 to 4, Chapter 5 describes a simple but powerful decision support system for water management that includes water-related energy use and GHG emissions not solely from the water operations, but also from final water end uses, including demands from cities, agriculture, environment and the energy sector. The DSS combines a surface water management model with a simple groundwater model, accounting for their interrelationships, and also includes explicitly economic data to optimize water use across sectors during shortages and calculate return flows from different uses. Capabilities of the DSS are demonstrated on a case study over California's intertied water system over the historic period and some simulations are run to highlight water and energy tradeoffs. Results show that urban end uses account for most GHG emissions of the entire water cycle, but large water conveyance produces significant peaks over the summer season. The carbon footprint of the entire water cycle during this period, according to the model, was 21.43 millions of tons of CO2/year, what was roughly 5% of California's total GHG emissions. The last two chapters discus and summarize the thematic and methodological contribu-tions and looks for further research presenting and discussing the research gaps and research questions that this dissertation left open. / [ES] El primer capítulo utiliza la sequía de California para identificar las amenazas económicas de la escasez de agua en los sistemas de producción de alimentos, energético y medioambiental para presentar las múltiples interacciones entre estos recursos. La segunda parte del primer capítulo centra el objetivo de la tesis, la relación entre el agua y la energía, presenta la revisión de la literatura identificando los vacíos, describe los objetivos y las cuestiones que busca responder esta investigación, explica la metodología seguida, y describe la organización de la tesis. En el segundo capítulo se desarrolla un modelo de usos finales de agua, contando con la energía y las emisiones de GEI asociados utilizando distribuciones de probabilidad para los parámetros que afectan al uso del agua en 10 ciudades en California. Como resultados principales se obtiene que las emisiones de GEI asociadas al consumo residencial de agua representan el 2% del total de emisiones per cápita, y se presenta la variabilidad debida a las condiciones locales. Los impactos de algunas prácticas comunes de ahorro de agua y energía son calculadas simulando diferente escenarios. Basado en ese modelo, el Capítulo 3 se presenta un modelo de optimización probabilísticos en dos periodos considerando variables de decisión de modificaciones técnicas y de comportamiento en relación al consumo de agua para obtener las estrategias más económicas para minimizar las facturas de agua y energía. Los resultados proporcionan un límite superior para el ahorro doméstico, y muestran mayores tasas de adopción para reducir usos de agua que son más intensivos en consumo energético cuando la energía se incluye, resultando en una reducción del 24% de uso de agua adentro de las casas, que representa un 30% en reducción de energía y un 53% de emisiones de GEI, ambos relacionados con el consumo de agua. Para completar el ciclo urbano del agua, el Capítulo 4 desarrolla primero un modelo horario de usos de agua incluyendo la energía asociada y después se calibra un modelo de agua y energía en el abastecimiento, tratamiento y bombeo de agua, y el tratamiento de agua residual, utilizando datos reales de East Bay Municipal Utility District en California. Los costes horarios de energía para las compañías de agua y energía, así como las emisiones de GEI son estimadas. Los resultados muestran que los usos finales son responsables del 95% de la energía relacionada con el uso del agua, pero que el 5% restante tiene un coste de 12 millones de dólares anualmente. Teniendo en cuenta los resultados obtenidos en los capítulos 2, 3 y 4, el Capítulo 5 describe un sistema de apoyo de decisión (SSD) para gestión de recursos hídricos incluyente energía y emisiones de GEI no sólo de la gestión del agua, sino también de usos finales del agua, incluyendo demandas urbanas, agrícolas, ambientales y del sector energético. El SSD combina un modelo de agua superficial con uno de agua subterráneo, incluyendo sus interacciones, y también incluye explícitamente datos económicos para optimizar el uso del agua durante periodos de sequía. Las posibilidades del SSD son demostradas en un caso de estudio aplicado a un modelo simplificado del sistema de recursos hídricos de California. Los resultados muestran que los usos finales del agua en zonas urbanas son responsables de la mayoría de las emisiones de GEH, pero que las grandes infrastructures de transporte de agua producen importante picos en verano. De acuerdo con el modelo, la huella de carbón del ciclo del agua en California es de 21.43 millones de toneladas de CO2/año, lo que significa aproximadamente el 5% del total de emisiones de GEI del estado. Los últimos dos capítulos resumen y discuten las contribuciones temáticas y metodológicas de esta tesis, presentando nuevas líneas de investigación que se derivan de este trabajo. / [CA] El primer capítol utilitza la sequera de Califòrnia per a identificar les amenaces econòmiques de l'escassesa d'aigua en els sistemes de producció d'aliments, energètic i mediambiental per a presentar les múltiples interaccions entre estos recursos. La segona part del primer capítol centra l'objectiu de la tesi, la relació entre l'aigua i l'energia, presenta la revisió de la literatura identificant els buits, descriu els objectius i les qüestions que busca respondre esta recerca, explica la metodologia seguida, i descriu la organització de la tesi. Al segon capítol es desenvolupa un model d'usos finals d'aigua, comptant amb l'energia i les emissions de GEH associats utilitzant distribucions de probabilitat per als paràmetres que afecten a l'ús de l'aigua en 10 ciutats en Califòrnia. Com a resultats principals s'obté que les emissions de GEH associades al consum residencial d'aigua representen el 2% del total d'emissions per càpita, i es presenta la variabilitat deguda a les condicions locals. Els impactes d'algunes pràctiques comunes d'estalvi d'aigua i energia són calculades simulant diferent escenaris. Basat en eixe model, al Capítol 3 es presenta un model d'optimització probabilístics en dos períodes considerant variables de decisió de modificacions tècniques i de comportament en relació al consum d'aigua per a obtindre les estratègies més econòmiques per a minimitzar les factures d'aigua i energia. Els resultats proporcionen un límit superior per a l'estalvi domèstic, i mostren majors taxes d'adopció per a reduir usos d'aigua que són més intensius en consum energètic quan l'energia es incluïda, resultant en una reducció del 24% d'ús d'aigua a dins de les cases, que representa un 30% en reducció d'energia i un 53% d'emissions de GEH, ambdós relacionats amb el consum d'aigua. Per a completar el cicle urbà de l'aigua, el Capítol 4 desenvolupa primer un model horari d'usos d'aigua incloent l'energia associada i després es calibra un model d'aigua i energia en l'abastiment, tractament i bombeig d'aigua i al tractament d'aigua residual, utilitzant dades reals de East Bay Municipal Utility District en Califòrnia. Els costs horaris d'energia per a les companyies d'aigua i energia, així com les emissions de GEH són estimades. Els resultats mostren que els usos finals són responsables del 95% de l'energia relacionada amb l'ús de l'aigua, però que el 5% restant té un cost de 12 milions de dolars anualment. Algunes simulacions analitzen els beneficis econòmics potencials de mesures de gestió de demanda d'aigua. La petjada de carbó total del cicle urbà de l'aigua s'estima en 405 kg CO2/any representant el 4.4% de les emissions per càpita en Califòrnia. Tenint en compte els resultats obtesos en els capítols 2, 3 i 4, el Capítol 5 descriu un sistema de suport de decisió (SSD) per a gestió de recursos hídrics incloent energia i emissions de GEH no sols de la gestió de l'aigua, sinó també del úsos finals de l'aigua, incloent demandes urbanes, agrícoles, ambientals i del sector energètic. El SSD combina un model d'aigua superficial amb un d'aigua subterrànea, incloent les seues interrelacions, i també inclou explícitament dades econòmiques per a optimitzar l'ús de l'aigua durant períodes de sequera. Les possibilitats del SSD són demostrades en un cas d'estudi aplicat a un model simplificat del sistema de recursos hídrics de Califòrnia. Els resultats mostren que els usos finals de l'aigua en zones urbanes són responsables de la majoria de les emissions de GEH, però que les grans infrastructures de transport d'aigua produïxen important pics a l'estiu. D'acord amb el model, la petjada de carbó del cicle de l'aigua a Califòrnia és de 21.43 milions de tones de CO2/any, el que significa aproximadament el 5% del total d'emissions de GEH a l'estat. Els últims dos capítols resumeixen i discuteixen les contribucions temàtiques i metodològiques d'esta tesi, presentan / Escrivà Bou, À. (2015). The Water-Energy Nexus: a bottom-up approach for basin-wide management [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/59451 / Premios Extraordinarios de tesis doctorales / Compendio
24

Building a Water-Energy Nexus Modelling Tool for New York City : Development of a NYC WaterMARKAL model

Segerström, Rebecka January 2011 (has links)
Increasing demands for energy and water from a growing urban population challenges resource availability and infrastructure capacity in cities worldwide. Planning for infrastructure systems development to meet growing demands has traditionally been done separately, not regarding that these systems are in many aspects interlinked. New York City has well developed systems for supplying these basic needs, but they are among the oldest in the country and may not suffice the needs of a growing population. Meanwhile, ambitious city-planning documents recognize opportunities for holistic planning focused on resource efficiency and long-term sustainability. This thesis aims to develop a foundation for quantitative modelling of how water and energy consumption may be affected by political decisions in New York City. The MARKAL (MARKet ALlocation) framework, commonly used to model long-term energy systems developments, is expanded to include the NYC’s water system. Relevant water system technologies are quantified with economic parameters, energy input and greenhouse gas emissions to give an as realistic as possible description of the entire water system. When combined with the existing MARKAL-model over NYC's energy system, the test runs of the model clearly shows impacts on energy consumption from water system regulations. These preliminary results are not applicable to support urban policy-making at this stage. However, with further development of the model as well as improvements in data quality it is perceived that this integrated water-energy model has the potential to become a powerful decision support tool for joint planning of water and energy systems developments in New York City. This Master thesis has been conducted in collaboration with the Energy Policy and Technology Analysis Group of the Sustainable Energy Technologies Department at Brookhaven National Laboratory, U.S.A.
25

Urban Living Labs som medel för samverkan och deltagande i mat-vatten-energi nexus : En fallstudie av CRUNCH Rosendal / Urban Living Labs as a means of collaboration and participation in the food-water-energy nexus : A case study of CRUNCH Rosendal

Gabrielsson, Louise January 2022 (has links)
Världens befolkning och städer växer. I takt med detta ökar efterfrågan på tillgångar av mat, energi och vatten och det finns efterfrågan på tillvägagångssätt som tar hänsyn till både synergier och konflikter mellan dessa. Ett projekt som syftade till att skapa kunskap inom dessa samband genom att använda så kallade Urban Living Labs, ULLs, var det transnationella projektet CRUNCH. Urban Living Labs kan beskrivas som en slags samling tillvägagångssätt som betonar experimentella tillvägagångssätt och en hög nivå av deltagande och samskapande. Men ULLs har visat sig kunna se mycket olika ut och den här studien är ett bidrag till den växande empirin inom ämnet. Studien analyserade hur en av de deltagande städerna inom CRUNCH arbetat med samverkan och samskapande och vilka hinder och möjligheter ULL har som tillvägagångssätt för deltagande, samverkan och samskapande. Detta gjordes genom en kvalitativ fallstudie av Uppsalas ULL Rosendal och analyserades genom teorier om deltagande och kollaborativ governance. Studien fann att deltagandet var smalt och främst skedde genom konsultation och information. De främsta möjligheterna till samarbete verkade vara de inledande villkoren och ett ömsesidigt beroende mellan parterna för att få finansiering till att utveckla sina idéer. De främsta hindren verkade finnas i en obalans i resurser vad gäller finansiering och möjligheter att delta. Men det kanske allra främsta hindret var dock en bristande delad förståelse av begreppet ULL. Begreppet sattes snarare som en ”stämpel” på projekt som redan fanns utan att tillföra dem något extra i form av deltagande eller samverkan. / The world's population and cities are growing. As the demand for food, energy and water resources increases there is a demand for approaches that consider both synergies and conflicts between them. One project that aimed to create knowledge in this nexus by using something called Urban Living Labs, ULLs, was the transnational project CRUNCH. Urban Living Labs can be described as a collection of approaches that emphasizes experimental approaches and a high level of participation and co-creation. But ULLs have been shown to take a variety of different forms and this study is a contribution to the growing empirical evidence in the subject. The study analysed how one of the participating cities within CRUNCH worked with collaboration and co-creation and what obstacles and opportunities ULL has as an approach for participation, collaboration, and co-creation. This was done through a qualitative case study of Uppsala's ULL Rosendal and analysed through theories of participation and collaborative governance. The study found that participation was narrow and mainly took place through consultation and information. The main opportunities for cooperation seemed to be the initial starting conditions and an interdependence between the partners to get funding to develop their ideas. The main obstacles seemed to be resource imbalances in terms of funding and means to participate. But perhaps the main obstacle was a lack of shared understanding of the main concept of ULL. The term was rather applied as a label on projects that already existed, without adding anything extra to them in terms of participation or collaboration.
26

Mathematical and Molecular Modeling of Ammonia Electrolysis with Experimental Validation

Estejab, Ali 14 June 2018 (has links)
No description available.
27

Water Supply Infrastructure Modeling and Control under Extreme Drought and/or Limited Power Availability

January 2019 (has links)
abstract: The phrase water-energy nexus is commonly used to describe the inherent and critical interdependencies between the electric power system and the water supply systems (WSS). The key interdependencies between the two systems are the power plant’s requirement of water for the cooling cycle and the water system’s need of electricity for pumping for water supply. While previous work has considered the dependency of WSS on the electrical power, this work incorporates into an optimization-simulation framework, consideration of the impact of short and long-term limited availability of water and/or electrical energy. This research focuses on the water supply system (WSS) facet of the multi-faceted optimization and control mechanism developed for an integrated water – energy nexus system under U.S. National Science Foundation (NSF) project 029013-0010 CRISP Type 2 – Resilient cyber-enabled electric energy and water infrastructures modeling and control under extreme mega drought scenarios. A water supply system (WSS) conveys water from sources (such as lakes, rivers, dams etc.) to the treatment plants and then to users via the water distribution systems (WDS) and/or water supply canal systems (WSCS). Optimization-simulation methodologies are developed for the real-time operation of water supply systems (WSS) under critical conditions of limited electrical energy and/or water availability due to emergencies such as extreme drought conditions, electric grid failure, and other severe conditions including natural and manmade disasters. The coupling between WSS and the power system was done through alternatively exchanging data between the power system and WSS simulations via a program control overlay developed in python. A new methodology for WDS infrastructural-operational resilience (IOR) computation was developed as a part of this research to assess the real-time performance of the WDS under emergency conditions. The methodology combines operational resilience and component level infrastructural robustness to provide a comprehensive performance assessment tool. The optimization-simulation and resilience computation methodologies developed were tested for both hypothetical and real example WDS and WSCS, with results depicting improved resilience for operations of the WSS under normal and emergency conditions. / Dissertation/Thesis / Doctoral Dissertation Civil, Environmental and Sustainable Engineering 2019

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