173 research outputs found

    La electromovilidad como potenciador de la cuota de renovables en sistemas eléctricos en regiones aisladas: El caso de las Islas Canarias

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    This doctoral thesis is divided into three chapters. These are linked to a single common axis, which is the impact of the electromobility in islanded regions, exploring two different approaches: Supply and demand side. Chapter 1 and 2 address the supply side, focusing on the role of the electric vehicles as energy storage system in isolated regions. These two chapters have been published in two international journals, included in the Journal of Citation Reports. Chapter 1 was published in Sustainability Journal in 2015; and chapter 2, in Modern Power System and Clean Energy Journal in 2016. Chapter 3 addresses the demand side, deepening in aspects that define the potential buyer of the electric vehicle. This chapter has been submitted to Renewable and Sustainable Energy Reviews Journal and its current state is revised and resubmitted. Chapter 1. Impact of Electric Vehicle as Distributed Energy Storage in Isolated Systems: The case of Tenerife. Isolated regions are highly dependent on fossil fuels. The use of endogenous sources and the improvement in energy efficiency in all consumption activities are the two main methods to reduce the dependence on petroleum-derived fuels. Tenerife offers excellent renewable resources (extensive long periods of sun and wind). However, the massive development of these technologies could cause important operational problems within the electric power grids, because of the small size of its system. In this chapter, it is explored the option of coupling an electric vehicle fleet as a distributed energy storage system to boost the share of renewable energies in an isolated power system, i.e., Tenerife island. A model simulator has been used to evaluate five key outputs under alternative scenarios, which are: the renewable share, the energy spilled, the CO2 emissions, the levelised cost of generating electricity, and fuel dependence. A total amount of 30 different scenarios have been evaluated in comparison with the current situation, combining a gradual renewable installed capacity and the introduction of an electric vehicle fleet using alternative charging strategies. Results show that the impact of 50,000 electric vehicles would increase the renewable share in the electricity mix of the island up to 30%, reduce CO2 emissions by 27%, the total cost of electric generation by 6% and the oil internal demand by 16%. Chapter 2. Complementarity of electric vehicles and pumped-hydro as energy storage in small isolated energy systems: case of La Palma, Canary Islands. In this chapter, we analyse a different island in the Canary Islands, which shows different characteristics than Tenerife. The island of La Palma is located on the northwest of the Canary Islands, and its electric system is fairly small. Sustainability policies planned by local authorities are aimed to increase the share of renewable energies and the reduction of fossil energies. However, intermittence and the concentration of unmanageable renewable energies in few locations may hinder the operation of the system. In order to solve these problems, energy storage plays an essential role. The aim of this chapter is to analyse the effects of the introduction of two possible alternatives as a form of energy storage: pumped hydro storage and electric vehicles. For this, we use a simulation model adapted to the features of La Palma, considering different scenarios and the existence of a pumped-hydro energy storage system. Results show that, in the best-case scenario, the installation of an additional 25 MW from renewables (more than double the current power), supported by 20 MW of pumped hydro storage and a fleet of 3361 electric vehicles, would allow the current share of renewables to increase from 11% (in 2015) to 49%. Furthermore, this would lead to a 26% reduction in CO2 emissions, a 10% in costs of generated kWh and a 19% in energy dependence. Chapter 3. Willingness to pay for electric vehicles in island regions: the case of Tenerife, Canary Islands. Electric vehicles could be a sustainable solution to reduce final energy consumption and carbon emissions in the road transport sector. Moreover, mobility characteristics of drivers (i.e., the average driving distance) fit better with current electric vehicle technical features on a small island than in mainland. In this chapter, the penetration of electric vehicles in Tenerife (Canary Islands) is analysed, which is still quite low. Based on data collected through a face-to-face contingent valuation method, the willingness to change and the willingness to pay for an electric vehicle on the island are estimated, which are key factor to understand the potentiality of electric vehicle penetration. In order to provide an appropriate profile of a potential electric car buyer, in the second part of the chapter we analyse the impact of a set of explanatory variables on both willingness to change and willingness to pay. It has been found that providing information about basic properties of an electric cars and environmental concerns are key factors for willingness to change, while income level, mobility patterns, environmental concerns and technological attitude of individuals are found to be important factors to determine willingness to pay

    Measuring energy poverty in Spain with the new EU expenditure-based indicators

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    [EN] This paper analyzes energy poverty in Spain between 2016 and 2021, using the new European primary indicators that relate household income to their energy expenditure, called expenditure-based indicators. The objective of the study is to determine the characteristics of the households most vulnerable to energy poverty in Spain, that is, with a greater probability of incurring in this situation. The determinants that influence energy poverty are identified through machine learning models: linear regression using bootstraping and random forest using repeated cross-validation. The problem addressed is key in the current economic and regulatory context of the energy transition, and it is essential to provide tools to measure its impact and analyze the causes.Mendoza Aguilar, J.; Ramos-Real, F.; Ramírez-Díaz, A. (2023). Measuring energy poverty in Spain with the new EU expenditure-based indicators. Editorial Universitat Politècnica de València. 213-214. http://hdl.handle.net/10251/20178321321

    Metodología para priorizar la inversión en irrigación en zonas rurales deprimidas

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    La construcción de infraestructura para la pequeña irrigación demanda grandes inversiones de capital que aumentan por desconocimiento de los aspectos sociales, culturales y técnicos de las regiones susceptibles de inversión. La carencia de información hidroclimatológica confiable, sumada a la debilidad organizacional que presentan comunidades deprimidas, dificulta su participación en las labores de planificación y limitan el éxito de muchos proyectos de riego. Para seleccionar predios con las características más favorables de inversión en la infraestructura de riego en la zona norte del departamento del Cauca (Colombia), y determinar aquellos que ofrecían las características sociales y económicas con mayor potencial de éxito, se aplicaron criterios de tipo cualitativo y se construyeron indicadores de tipo cuantitativo para priorizar los recursos financieros disponibles y facilitar la toma de decisiones. El objetivo consistió en maximizar la inversión garantizando su recuperación y beneficiando al mayor número de usuarios. Los predios evaluados fueron 400, de los cuales se seleccionaron 84. El proyecto tuvo duración de 42 meses, periodo durante el cual se realizó el diseño y construcción de la infraestructura básica de riego a los predios escogidos. Se construyeron captaciones directas sobre fuentes de agua superficial y pozos para aprovechar agua subterránea. Los costos de la inversión fueron menores a los estimados por la FAO para este tipo de obras.The infrastructure for small irrigation systems demands costly investment which may become increased as many social and technical aspects related to the concerns of regions susceptible to investment remain unknown. The lack of both information and a social network supporting planning and design tasks constitute factors affecting many irrigation projects, consigning them to failure. Some indicators were prepared for constructing an irrigation system in the north of the Cauca department in Colombia which, in turn, led to determining investment priorities and facilitated decisionmaking. The indicators guaranteed that the construction would benefit the greatest number of users, assuring wider irrigation coverage. The project lasted forty-two months; the basic irrigation system was designed and constructed during this time, alternating direct reception via surface water sources and digging wells to use groundwater. Investment costs were lower than estimated FAO reference ones

    Gestión de cuencas y su influencia en la erosión hídrica por efecto del cambio climático en la Gerencia Departamental Agro Rural, La Libertad, 2017

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    La presente investigación tuvo como finalidad analizar la influencia de la gestión de cuencas en la erosión hídrica por efecto del cambio climático, en la Gerencia Departamental Agro Rural, La Libertad – 2017. El método de investigación es cuantitativo, el diseño ha seguido los parámetros establecidos para una investigación no experimental. Se ha manejado dos cuestionarios, propiamente validados para la acopio de datos, propias de las variables, procesando la información mediante el software de estadística para ciencias sociales SPSS v23, siendo los resultados mostrados en tablas y figuras estadísticas. La población estuvo conformada por 36 trabajadores de la Gerencia Departamental Agro Rural, La Libertad – 2017. Se utilizó el coeficiente de contingencia del estadístico de prueba Tau-b de Kendall es 0,264, con nivel de significancia menor al 5% de significancia estándar (P 0,028 < 0.05); por lo que se admite la hipótesis de investigación y se rechaza la hipótesis nula y para la correlación causal se utilizó el estadístico de prueba Rho de Spearman, encontrándose Rs=0,271, lo que demuestra que la gestión de cuencas influye significativamente sobre la erosión hídrica por efecto del cambio climático en la Gerencia Departamental Agro Rural – 2017, es el regular. El estudio es de gran importancia porque en base a las conclusiones obtenidas nos orientará a fomentar el cambio en la actitud para la gestión de cuencas de los servidores públicos del Programa Agro Rural Gerencia Departamental La Libertad para asumir con responsabilidad el cumplimiento de las medidas de gestión de cuencas; generando seguridad en la población ante los diversos fenómenos de inundaciones, derrumbes y avalanchas debido a la erosión hídrica

    Gestión de cuencas y su influencia en la erosión hídrica por efecto del cambio climático en la Gerencia Departamental Agro Rural, La Libertad, 2017

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    La presente investigación tuvo como finalidad analizar la influencia de la gestión de cuencas en la erosión hídrica por efecto del cambio climático, en la Gerencia Departamental Agro Rural, La Libertad – 2017. El método de investigación es cuantitativo, el diseño ha seguido los parámetros establecidos para una investigación no experimental. Se ha manejado dos cuestionarios, propiamente validados para la acopio de datos, propias de las variables, procesando la información mediante el software de estadística para ciencias sociales SPSS v23, siendo los resultados mostrados en tablas y figuras estadísticas. La población estuvo conformada por 36 trabajadores de la Gerencia Departamental Agro Rural, La Libertad – 2017. Se utilizó el coeficiente de contingencia del estadístico de prueba Tau-b de Kendall es 0,264, con nivel de significancia menor al 5% de significancia estándar (P 0,028 < 0.05); por lo que se admite la hipótesis de investigación y se rechaza la hipótesis nula y para la correlación causal se utilizó el estadístico de prueba Rho de Spearman, encontrándose Rs=0,271, lo que demuestra que la gestión de cuencas influye significativamente sobre la erosión hídrica por efecto del cambio climático en la Gerencia Departamental Agro Rural – 2017, es el regular. El estudio es de gran importancia porque en base a las conclusiones obtenidas nos orientará a fomentar el cambio en la actitud para la gestión de cuencas de los servidores públicos del Programa Agro Rural Gerencia Departamental La Libertad para asumir con responsabilidad el cumplimiento de las medidas de gestión de cuencas; generando seguridad en la población ante los diversos fenómenos de inundaciones, derrumbes y avalanchas debido a la erosión hídrica

    Measuring online teaching service quality in higher education in the COVID-19 environment

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    The use of the Internet to develop new technologies has generated a considerable change in teaching and student learning in higher education. The pandemic caused by COVID-19 has forced universities to switch from face-to-face to online instruction. Furthermore, this transfer process was planned and executed quickly, with urgent redesigns of courses originally conceived for live teaching. The aim of this work is to measure the service quality of online teaching delivered during the COVID- 19 period. The methodology was based on an importance-performance analysis using a structural equations model. The data were obtained from a sample of 467 students attending a university in southern Spain. The results reveal five priority attributes of online teaching that need to be improved in order to enhance the service quality of the virtual instruction provided to students. Universities need to redefine their online format by integrating methodological and technological decisions and involving collaboration between teachers, students and administration staff and services. The results do not apply to educational institutions that exclusively teach courses online, but to those institutions that had to rapidly adapt, and shift course material originally designed for face-to-face training

    Interaction Networks Help to Infer the Vulnerability of the Saproxylic Beetle Communities That Inhabit Tree Hollows in Mediterranean Forests

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    Insect communities are facing contrasting responses due to global change. However, knowledge on impacts of communities’ reorganizations is scarce. Network approaches could help to envision community changes in different environmental scenarios. Saproxylic beetles were selected to examine long-term variations in insect interaction/diversity patterns and their vulnerability to global change. We evaluated interannual differences in network patterns in the tree hollow–saproxylic beetle interaction using absolute samplings over an 11-year interval in three Mediterranean woodland types. We explored saproxylic communities’ vulnerability to microhabitat loss via simulated extinctions and by recreating threat scenarios based on decreasing microhabitat suitability. Although temporal diversity patterns varied between woodland types, network descriptors showed an interaction decline. The temporal beta-diversity of interactions depended more on interaction than on species turnover. Interaction and diversity temporal shifts promoted less specialized and more vulnerable networks, which is particularly worrisome in the riparian woodland. Network procedures evidenced that saproxylic communities are more vulnerable today than 11 years ago irrespective of whether species richness increased or decreased, and the situation could worsen in the future depending on tree hollow suitability. Network approaches were useful for predicting saproxylic communities’ vulnerability across temporal scenarios and, thus, for providing valuable information for management and conservation programs.Grants PID2020-115140RB-I00 and CGL2009-09656 funded by MCIN/AEI/10.13039/501100011033

    "Antígenos de Helicobacter Pylori en muestras fecales de la población que reside en el asilo San Antonio, departamento de San Miguel. Año 2019"

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    RESUMEN: La bacteria Helicobacter pylori se considera la responsable para el desarrollo de enfermedades del tracto digestivo cómo son la gastritis crónica, úlcera péptica y el adenocarcinoma gástrico; esta bacteria evoluciona constantemente en el ser humano y se transmite de persona a persona a través de vías de adquisición como la Oral-Oral, Fecal-Oral, Gastro-Oral y por factores vulnerables como el hacinamiento, alimentos crudos o mal cocidos, ingesta de café, alcohol y consumo de tabaco ya que estos ayudan a la proliferación bacteriana. Esta infección es más frecuente en adultos mayores debido al debilitamiento de la membrana estomacal debido a la edad y a la alteración del mecanismo de defensa. El objetivo de la presente investigación fue Determinar Antígenos de Helicobacter pylori, en la población que reside en el Asilo San Antonio, del Departamento de San Miguel. La metodología utilizada fue de tipo prospectivo, transversal, descriptivo y de laboratorio. Resultados: La población que reside en el Asilo San Antonio del Departamento de San Miguel, resulto positiva a la prueba rápida de Antígenos de Helicobacter pylori en heces con un 39.10%, donde las personas que laboran en dicha institución presentaron resultados positivos con 55.60%, mientras que un 44.40% de infección corresponde a los adultos mayores, los rangos de edad más afectados fueron de 68-83 años con el 38.90% y de 19-34 años con 33.30%, además el sexo más afectado fue el sexo más afectado fue el femenino con el 72.20%. ABSTRACT: The Helicobacter pylori bacterium is considered responsible for the development of digestive tract diseases such as chronic gastritis, peptic ulcer and gastric adenocarcinoma; This bacterium constantly evolves in humans and is transmitted from person to person through acquisition routes such as Oral-Oral, Fecal-Oral, Gastro-Oral and by vulnerable factors such as overcrowding, raw or undercooked food, intake of coffee, alcohol and tobacco consumption as these help bacterial proliferation. This infection is more frequent in older adults due to the weakening of the stomach membrane due to age and the alteration of the defense mechanism. The objective of the present investigation was to determine Helicobacter pylori Antigens, in the population that resides in the San Antonio Asylum, in the Department of San Miguel. The methodology used was prospective, cross-sectional, descriptive and laboratory. Results: The population that resides in the San Antonio Asylum of the Department of San Miguel, was positive to the rapid test of Helicobacter pylori Antigens in feces with 39.10%, where the people who work in said institution presented positive results with 55.60%, while 44.40% of infection corresponds to older adults, the most affected age ranges were 68-83 years with 38.90% and 19-34 years with 33.30%, in addition, the most affected sex was the most affected sex was the female with 72.20%

    Perfil sociodemográfico y laboral de los inmigrantes interestatales indígenas en Quintana Roo (México), 1990-2020

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    En este artículo se analiza el perfil sociodemográfico y laboral de los inmigrantes interestatales hablantes de lengua indígena (HLI) en Quintana Roo en cinco años censales: 1990, 2000, 2010, 2015 y 2020. Se constató que los habitantes de Quintana Roo son principalmente inmigrantes y que la entidad presentó la tasa de migración indígena más alta en México. Los inmigrantes indígenas provienen principalmente de estados contiguos a Quintana Roo y se dirigen a los municipios de Benito Juárez y Solidaridad, donde se ubican Cancún y Playa del Carmen, localidades que forman parte de la denominada Riviera Maya. Los inmigrantes HLI presentan un rasgo masculinizado en casi todos los cortes de tiempo analizados, en contraste con los no hablantes de lengua indígena (NHLI), en quienes ha existido una tendencia al equilibrio entre los dos sexos. El perfil laboral tanto en los inmigrantes HLI y NHLI presentan condiciones que denotan su baja calificación
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