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

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, presentanEscrivà 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/10251/59451TESISPremios Extraordinarios de tesis doctoralesCompendi

Análisis hidroeconómico de la adaptación al cambio climático en sistemas de gestión de recursos hídricos. Aplicación a la cuenca del Júcar

[ES] A pesar de las incertidumbres, hoy en día existe bastante consenso en que estamos dentro de un ciclo de cambio climático en que la actividad del hombre es la causa principal del mismo. El último informe del Grupo Intergubernamental de Expertos sobre el Cambio Climático no habla de certeza, pero sí de una probabilidad del 90% de que esto sea así (IPCC, 2007). Además, los últimos estudios sobre cambio climático proyectan importantes disminuciones de los recursos en las cuencas mediterráneas, con importantes impactos ambientales, económicos y sociales (Iglesias et al., 2007). Aunque cada vez existen más trabajos que analizan los impactos y las consecuencias que producirá el cambio climático en los recursos hídricos y en sus sistemas de gestión, hay pocos trabajos en la bibliografía que aborden la definición de posibles estrategias de adaptación y su análisis posterior. Es por ello que en el presente trabajo se desarrolla una metodología completa para tratar de definir y analizar hidroeconómicamente las estrategias de adaptación al cambio climático en los sistemas de gestión de recursos hídricos y se realiza la aplicación de esta metodología a la cuenca del Júcar. En primer lugar se han obtenido las variables climáticas de todos los Modelos Climáticos Regionales del proyecto ENSEMBLES para la cuenca del Júcar y se han comparado con las series históricas existentes, seleccionando únicamente aquellos modelos que presentan un buen ajuste de las variables históricas. Posteriormente, con las predicciones futuras de estos MCRs se han generado series futuras de las variables climáticas a partir de la perturbación de las series históricas mediante una técnica de reescalado estadístico (Pulido-Velázquez, 2011). El siguiente paso es el de ajustar un modelo lluvia-escorrentía pseudo-distribuido con el que obtener las aportaciones de los escenarios a partir de los datos climáticos futuros. A continuación se han estimado las demandas futuras a partir de proyecciones estadísticas de población ¿para las demandas urbanas¿ y a partir del cálculo de las demandas netas para los cultivos agrícolas en función de los datos climáticos futuros. Con las aportaciones y las demandas de los escenarios futuros se implementa un modelo de gestión de recursos hídricos (AQUATOOL) que se simula para cada uno de los escenarios propuestos ¿histórico, de corto plazo (2011-2040), de medio plazo (2041-2070) y de largo plazo (2071-2100)¿, obteniendo resultados del sistema para cada uno de ellos. Con estos resultados, y mediante la definición de las funciones económicas de demanda se realiza un análisis hidroeconómico mediante el cual se obtienen los resultados del coste de escasez asociado a los déficits en las demandas. Finalmente, a partir de los indicadores del estado del sistema en cada uno de los escenarios obtenidos a partir de la metodología definida por Pulido-Velázquez et al. (2011), se diagnostica el estado del sistema y se considera la necesidad de definir unas estrategias de adaptación, sobre todo para el escenario largo plazo, planteándose unas medidas concretas que son simuladas mediante el sistema de gestión de recursos hídricos y analizadas hidroeconómicamente.[EN] Despite the uncertainties, there is plenty of consensus today that we are inside a climate change cycle in which the human activity is the main cause of itself. The last report of the Intergovernmental Panel on Climate Chance does not talk about certainty, but of a probability of 90% that it happens this way (IPCC, 2007). Moreover, the last studies on climate change project relevant reductions on resources in the Mediterranean basins, with important environmental, economic and social impacts (Iglesias et al., 2007). Although the increasing number of reports that analyse the impacts and consequences that the climate change will produce in the hydraulic resources and their management systems, there are few works in the bibliography that take into account the definition of possible adaptation strategies and their later analysis. That is why the present work develops a complete methodology that tries to define and analyse hydro-economically the adaptation strategies on climate change of the water resources management systems and uses the Júcar basin as case study. First of all, the climate variables of every Regional Climate Model of the ENSEMBLES project have been obtained for the Júcar basin and they have been compared with the existing historical series, choosing only those models that present a good statistical fitting with the historic values. Later, with the future prediction of those RCM the future series of the climate variables have been generated from the perturbation with a statistical re-scaling technique of the historical series (Pulido-Velázquez, 2011). Next, a pseudo-distributed rainfall-runoff model has been adjusted with the future climate data in order to obtain the different scenarios inputs. Then, the future demands have been estimated from statistical projections on population ¿ for urban demands - and from the calculation of the net demands for the agricultural crops, according to the future climate data. With the inputs and the future scenarios demands a water resources management model (AQUATOOL) is implemented. The model is run for every proposed historic scenario ¿ short term (2011-2040), medium term (2041-2070) and long term (2071-2100) ¿, getting system results for each of them. With these results, and through the definition of the demand economic functions, a hydro-economic analysis is carried out. As a result, the costs of scarcity associated to the demand shortages are obtained. Finally, from the system status indicators of each of the scenarios obtained according to the methodology established in Pulido-Velázquez et al. (2011), the system status is diagnosed and the requirement to define some adaptation strategies is considered, especially for the long term scenario. In this case, concrete measures are settled and simulated with the water resources management system and hydro-economically analysed.Escrivà Bou, À. (2012). Análisis hidroeconómico de la adaptación al cambio climático en sistemas de gestión de recursos hídricos. Aplicación a la cuenca del Júcar. http://hdl.handle.net/10251/18402Archivo delegad

Modeling residential water and related energy, carbon footprint and costs in California

Starting from single-family household water end-use data, this study 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. Monte Carlo simulations are used to develop a large representative sample of households to describe variability in use, with water bills for each house for different utility rate structures. The water-related energy consumption for each household realization was obtained using an energy model based on the different water end-uses, assuming probability distributions for hot-water-use for each appliance and water heater characteristics. Spatial variability is incorporated to account for average air and household water inlet temperatures and price structures for each utility. Water-related energy costs are calculated using averaged energy price for each location. CO2 emissions were derived from energy use using emission factors. Overall simulation runs assess the impact of several common conservation strategies on household water and energy use. Results show that single-family water-related CO2 emissions are 2% of overall per capita emissions, and that managing water and energy jointly can significantly reduce state greenhouse gas emissions. (C) 2015 Elsevier Ltd. All rights reserved.This paper has been developed as a result of a mobility stay funded by the Erasmus Mundus Programme of the European Commission under the Transatlantic Partnership for Excellence in Engineering-TEE Project. The study has been partially supported by the Plan Nacional I+D+I 2008-2011 (Ministry of Science and Innovation, Spain), projects CGL2009-13238-C02-01 and CGL2009-13238-C02-02.Escrivà Bou, À.; Lund, J.; Pulido-Velazquez, M. (2015). Modeling residential water and related energy, carbon footprint and costs in California. Environmental Science and Policy. 50:270-281. https://doi.org/10.1016/j.envsci.2015.03.005S2702815

Saving energy from urban water demand management

This is the peer reviewed version of the following article: Escrivà Bou, Àlvar, Lund, JR., Pulido-Velazquez, M.. (2018). Saving energy from urban water demand management.Water Resources Research, 54, 7, 4265-4276. DOI: 10.1029/2017WR021448, which has been published in final form at http://doi.org/10.1029/2017WR021448. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] Water use directly causes a significant amount of energy use in cities. In this paper we assessed energy and carbon dioxide emissions related to each part of the urban water cycle and the consequences of some water demand management policies in terms of water, energy, and CO2 emissions in urban water users, water and energy utilities, and the environment. First, we developed an hourly model of urban water uses by customer category, including water-related energy consumption. Next, using real data from the East Bay Municipal Utility District in California, we calibrated a model of the energy used in water supply, treatment, pumping, and wastewater treatment by the utility, obtaining also energy costs. Then, using data from the California Independent System Operator, we obtained hourly costs of energy generation and transport to the point of use for the energy utility. Finally, using average emission factors reported by energy utilities, we estimated greenhouse gas emissions for the entire urban water cycle. Results for East Bay Municipal Utility District show that water end uses account for almost 95% of all water-related energy use; however, the remaining 5% of energy used by the utility still costs over USD12 million annually. The carbon footprint of the urban water cycle is 372 kg CO2/person/year, representing approximately 4% of the total per capita emissions in California. Several simulations analyze the consequences of different water demand management policies, resulting in significant economic impacts for water and energy utilities and environmental benefits by reducing CO2 emissions.This paper has been developed as a result of a mobility stay funded by the Erasmus Mundus Programme of the European Commission under the Transatlantic Partnership for Excellence in Engineering-TEE Project. This research was also partially supported by the IMPADAPT project (CGL2013-48424-C2-1-R and CGL2013-48424-C2-2-R) of the National Research Plan (Plan Estatal I+D+I 2013-2016), funded by the Spanish Ministry MINECO (Ministerio de Economia y Competitividad) and European Federation funds. Water and energy microdata were kindly provided by Frank Loge and Edward Spang, at the Center for Water and Energy Efficiency of the University of California, Davis, who are able to release the data under private agreements and to whom we are very grateful. The results can be totally reproduced using the summary tables included in the supporting information.cEscrivà Bou, À.; Lund, J.; Pulido-Velazquez, M. (2018). Saving energy from urban water demand management. Water Resources Research. 54(7):4265-4276. https://doi.org/10.1029/2017WR021448S4265427654

Economic Value of Climate Change Adaptation Strategies for Water Management in Spain s Jucar Basin

[EN] Although many recent studies have quantified the potential effects of climate change on water resource systems, the scientific community faces now the challenge of developing methods for assessing and selecting climate change adaptation options. This paper presents a method for assessing impacts and adaptation strategies to global change in a river basin system at different temporal horizons using a hydro-economic model. First, a multiobjective analysis selects climate change projections based on the fitting of the climate models to the historical conditions for the historical period. Inflows for climate change scenarios are generated using calibrated rainfall-runoff models, perturbing observed meteorological time series according to the projected anomalies in mean and standard deviation. Demands are projected for the different scenarios and characterized using economic demand curves. With the new water resource and demand scenarios, the impact of global change on system performance is assessed using a hydro-economic model with reliability and economic indices. A new economic loss index is defined to assess the economic equity of the system. Selected adaptation strategies are simulated to compare performance with the business-as-usual scenario. The approach is applied to the Jucar River water resource system, in eastern Spain, using climate projections from the European Union (EU) ENSEMBLES project. Results show that the system is vulnerable to global change, especially over the long term, and that adaptation actions can save Euro3-65million/year. (C) 2017 American Society of Civil Engineers.This research was partially supported by the IMPADAPT project (CGL2013-48424-C2-1-R and CGL2013-48424-C2-2-R) of the National Research Plan (Plan Estatal I+D+I 2013-2016), funded by the Spanish Ministry MINECO (Ministerio de Economia y Competitividad) and European Federation funds. It was also partially funded by the PMAFI06/14 project (UCAM). The work was also partially supported by a stay grant from the Erasmus Mundus Programme of the European Commission under the Transatlantic Partnership for Excellence in Engineering-TEE Project. The authors would like to thank Professor Jay R. Lund (University of California, Davis) for his insights. The ENSEMBLES data used in this work was funded by the EU FP6 Integrated Project ENSEMBLES (Contract Number 505539) whose support is gratefully acknowledged. The data can be downloaded from http://ensembles-eu.metoffice.com/.Escrivà Bou, À.; Pulido-Velazquez, M.; Pulido-Velázquez, D. (2017). Economic Value of Climate Change Adaptation Strategies for Water Management in Spain s Jucar Basin. Journal of Water Resources Planning and Management. 143(5):1-13. https://doi.org/10.1061/(ASCE)WR.1943-5452.0000735S113143

Developing a water-energy-GHG emissions modeling framework: Insights from an application to California's water system

[EN] Integrating processes of water and energy interdependence in water systems can improve the understanding of the tradeoffs between water and energy in management and policy. This study presents a development of an integrated water resources management model that includes water-related energy use and GHG emissions. We apply the model to a simplified representation of California's water system. Accounting for water demands from cities, agriculture, environment and the energy sector, and combining a surface water management model with a simple groundwater model, the model optimizes water use across sectors during shortages from an economic perspective, calculating the associated energy use and electricity generation for each water demand. The results of California's water system 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. Different policy scenarios show the significant tradeoffs between water, energy, and GHG emissions.Escrivà Bou, À.; Lund, J.; Pulido-Velazquez, M.; Hui, R.; Medellín-Azuara, J. (2018). Developing a water-energy-GHG emissions modeling framework: Insights from an application to California's water system. Environmental Modelling & Software. 109:54-65. doi:10.1016/j.envsoft.2018.07.011S546510