Influence of Population Income and Climate on Air Pollution in Cities due to Buildings: The Case of Spain

Article number 1051Half of the world’s population lives in cities. In addition, more than 40% of greenhouse gas emissions are produced in buildings in the residential and tertiary sectors. Therefore, cities, and in particular their buildings, have a great influence on these emissions. In fact, they are reflected in several of the United Nations’ Sustainable Development Goals. Any measure taken to reach these goals has a significant impact from the point of view of reducing greenhouse gases. An understanding of these goals is the basis of greenhouse gas mitigation. This work analyzed the CO2 emissions from the buildings in cities as a function of the economic income of their inhabitants. For this, databases published by official sources were used. The origins of the CO2 are usually emitted by buildings were analyzed—electrical and thermal, in the form of natural gas. Another variable that influences these emissions is climate. To study only the income variable, the influence of climate has been eliminated. Also, to facilitate analysis, an index has been introduced. As an example of application of the proposed methodology, Spanish cities with more than 50,000 inhabitants were studied. The analysis was carried out by household and by inhabitant. The results showed the following: the higher the income of the citizens, the higher the total and thermal emissions; thermal consumption is elastic, while electrical consumption is inelastic; emissions of electrical origin are almost constant; emissions from electrical energy are greater than those from thermal energy; as income increases, the ratio between emissions of electrical and thermal origin decreases

Towards the Achievement of the Sustainable Development Goals through Engineering Training for Labor Market Reintegration of Older Workers

The inclusion of training in the Sustainable Development Goals (SDGs) in higher education is essential to achieve them. In addition, labor market reintegration or improvement of older workers is a goal that an increasing number of people have set for themselves, especially in countries severely affected by crises. The union of these two premises has given rise to the application of a methodology in a master’s degree in engineering. This manuscript makes a double contribution: on the one hand, it presents the methodology with its application through a practical case; on the other hand, it covers how students perceive the application of non-traditional training techniques. The methodology is based on student-centered learning, using case-based teaching and inquiry-based learning. The students’ perception of this change in training was evaluated through a qualitative methodological approach for five consecutive years and through two types of surveys carried out each year, one of which involves comparison with traditional training methodologies. The results of the surveys show the favorable acceptance of this form of teaching, surpassing the results of traditional teaching methods by more than 25%. As a practical implication, this research identifies new ways of teaching complex subjects that facilitate training in SDGs and the subsequent labor market reintegration of older people

Corrección de tensiones en redes eléctricas de distribución mediante técnicas heurísticas

En este trabajo se desarrolla un método de control de potencia reactiva, basado en matrices de sensibilidades, que permite elegir la actuación necesaria para corregir las tensiones de una red eléctrica de forma que se mantengan siempre dentro de unos márgenes. Dicho método no es nuevo, pues se implementó en la red de transporte española en la década de los 90, aunque sí lo es el hecho de aplicarlo a una red de distribución. A lo largo del trabajo, se explica el funcionamiento de este método. A grandes rasgos, se comienza determinando si existe algún valor de tensión fuera de límites. En tal caso, se calculan las matrices de sensibilidades, que determinan la relación entre las variables de control y las magnitudes de interés del sistema, y se estudian los límites propios de las variables de control y los límites de operación del sistema eléctrico, para calcular las actuaciones máximas disponibles. Finalmente, habiendo determinado la/s variable/s de control que debe/n actuar mediante los “Coeficientes de Eficacia”, se calcula la actuación necesaria. Igualmente, para comprobar el funcionamiento de dicho método, se realizan ejemplos prácticos tanto en una red de transporte, entorno para el que fue concebido, como en una red de distribución, con y sin generación distribuida.Universidad de Sevilla. Grado en Ingeniería de Tecnologías Industriale

Actuaciones correctoras en redes de distribución en presencia de generación distribuida y recursos de almacenamiento

En este trabajo se desarrolla un método de corrección de situaciones de emergencia orientado a redes de distribución con presencia de generación distribuida y recursos de almacenamiento, pero que puede ser empleado también en redes de otras características. La gran ventaja de esta técnica es que permite emplear variables de control de diferente naturaleza a la vez que se considera el coste asociado a cada actuación, para resolver así las situaciones de emergencia. Algunos ejemplos de variables de control son: generadores distribuidos, recursos de almacenamiento, transformadores, baterías de condensadores y deslastres de carga. La metodología propuesta permite determinar sobre qué variables de control se debe actuar para corregir de forma más eficiente las tensiones en los nudos o las sobrecargas por las líneas o transformadores del sistema, considerando a su vez los límites de operación de la red, de forma que no se creen nuevas contingencias al corregir la situación de emergencia. Para tal fin, se emplean matrices de sensibilidades que permiten relacionar las variables de control disponibles con las magnitudes de interés del sistema eléctrico. Finalmente, dada la importancia de las sensibilidades en la metodología propuesta, se ha dedicado un capítulo al análisis del error asociado a cada una de las matrices de sensibilidades, pues su cálculo parte de realizar una aproximación lineal de las ecuaciones del flujo de cargas en torno al punto de operación. Esto permite establecer un rango seguro de actuación para cada una de las variables de control, donde se puede asegurar que el error asociado no va a superar un determinado valor preestablecido.Universidad de Sevilla. Máster de Ingeniería Industria

Herramienta de ayuda a la operación en redes activas de distribución en estado de emergencia

A lo largo de este trabajo se propone una herramienta de ayuda a la operación que permite corregir situaciones de emergencia en redes de distribución con alta presencia de generación distribuida y recursos de almacenamiento, aunque su uso es extensible a redes de otras características. La metodología que implementa esta herramienta permite crear un entorno donde comparar dispositivos de distinta naturaleza, de forma que se puede emplear un gran número de controles y considerar tanto aspectos técnicos como económicos para determinar la mejor actuación correctora. Algunos ejemplos de los controles considerados son: generadores distribuidos, recursos de almacenamiento, transformadores, baterías de condensadores o deslastres de carga. La herramienta desarrollada permite determinar sobre qué variables de control se debe actuar para corregir de forma más eficiente las tensiones en los nudos o las sobrecargas por las líneas o transformadores del sistema. A grandes rasgos, el funcionamiento del método propuesto es el que sigue. Se comienza determinando la tensión fuera de límites o la sobrecarga más crítica y se procede al cálculo de las matrices de sensibilidades, que determinan la relación entre las variables de control y las magnitudes de interés del sistema. Para determinar la mejor actuación, se estudian los límites propios de las variables de control y los límites de operación del sistema eléctrico, a fin de no crear nuevas contingencias o empeorar las ya existentes. Empleando los llamados Coeficientes de Eficacia y tomando en consideración el coste asociado a cada actuación, se elige(n) la(s) variable(s) de control que corregirá(n) de forma más eficiente la situación de emergencia y se calcula la actuación necesaria. Finalmente, se presentan varios ejemplos en redes de distribución de media y baja tensión en los que se pone en práctica la técnica desarrollada. Se puede comprobar en todos los casos estudiados cómo la herramienta propuesta corrige satisfactoriamente las situaciones de emergencia y devuelve al sistema a un estado de ausencia de problemas.Universidad de Sevilla. Máster en Sistemas de Energía Eléctric

Centralized Control of Distribution Networks with High Penetration of Renewable Energies

Distribution networks were conceived to distribute the energy received from transmission and subtransmission to supply passive loads. This approach, however, is not valid anymore due to the presence of distributed generation, which is mainly based on renewable energies, and the increased number of plug-in electric vehicles that are connected at this voltage level for domestic use. In this paper the ongoing transition that distribution networks face is addressed. Whereas distributed renewable energy sources increase nodal voltages, electric vehicles result in demand surges higher than the load predictions considered when planning these networks, leading to congestion in distribution lines and transformers. Additionally, centralized control techniques are analyzed to reduce the impact of distributed generation and electric vehicles and increase their effective integration. A classification of the different methodologies applied to the problems of voltage control and congestion management is presented.Unión Europea Convenio 764090Ministerio de Ciencia e Innovación CER-2019101

On the Remuneration to Electrical Utilities and Budgetary Allocation for Substation Maintenance Management

The liberalization of electricity markets has produced a great change in electrical utilities. One of these changes has affected the methodology for setting their remuneration. Depending on the country, these are different. Despite the wide range of remuneration methodologies for the electricity market of each country, they all feature one common element: the remuneration of operation and maintenance. One of the messages that this remuneration transmits is the need to extend the useful life of the facilities to allow sustainable development. This article focuses on the remuneration schemes of electrical utilities, the classification of substations for the definition of their maintenance programs, and the budget allocation for the execution of maintenance in these critical infrastructures. The particularity of these facilities, in which it is generally necessary to de-energize some of their parts for maintenance, has also been taken into account. To this end, a simple methodology currently used is presented based on the standardization of the bays of the substations and their classification into levels of importance. This classification into levels enables the facilities to be grouped according to similarities in their maintenance plans, although they differ from each other in terms of the periodicity of the application of maintenance procedures. This methodology guarantees a similar distribution of maintenance activities and financial needs over the years. In addition, the methodology allows one to know the importance of each substation (since the greater the equivalent weight, the greater the importance). Finally, the application of the proposed methodology in a real case is presented. It shows the simplicity, effectiveness, and lamination of the budgetary allocation of the proposed methodology, this being the main contribution of the formulation.Ministerio de Ciencia e Innovación PID2020-116433RB-I00Agencia Estatal de Investigación AEI/10.13039/5011000110

A fast non-decoupled algorithm to solve the load flow problem in meshed distribution networks

The purpose of this work is to compare the classical methods of power flow resolution (Newton–Raphson and Gauss–Seidel) with a more recent algorithm known as Alternating Search Direction (ASD), for which its equations, the steps to follow and the parameters to consider are described. In addition, a series of tests are carried out in different distribution networks where the reduction of execution time, accuracy, and robustness of the presented algorithm is demonstrated, taking as a reference the behavior of the well-known Newton–Raphson algorithm. Finally, the advantage of selecting certain parameters in the ASD algorithm is studied

Influence of population income on energy consumption for heating and its CO2 emissions in cities

Article number 4531As a result of the increase in city populations, and the high energy consumption and emissions of buildings, cities in general, and buildings in particular, are the focus of attention for public organizations and utilities. Heating is among the largest consumers of energy in buildings. This study examined the influence of the income of inhabitants on the consumption of energy for heating and the CO2 emissions in city buildings. The study was carried out using equivalized disposable income as the basis for the analysis and considered the economies of scale of households. The results are shown per inhabitant and household, by independently considering each city. Furthermore, to more clearly identify the influence of the population income, the study was also carried out without considering the influence of the climate. The method was implemented in the case of Spain. For this purpose, Spanish cities with more than 50,000 inhabitants were analyzed. The results show that, both per inhabitant and per household, the higher the income of the inhabitants, the greater the consumption of energy for heating and the greater the emissions in the city. This research aimed to help energy utilities and policy makers make appropriate decisions, namely, planning for the development of facilities that do not produce greenhouse gases, and enacting laws to achieve sustainable economies, respectively. The overall aim is to achieve the objective of mitigating the impact of emissions and the scarcity of energy resources

Influence of Population Income on Energy Consumption and CO2 Emissions in Buildings of Cities

More than half of the world’s population lives in cities. A large part of the emissions and energy consumption corresponds to buildings, both in the residential sector and in the service sector. This means that a large part of the measures taken by governments to reduce energy consumption and greenhouse gas emissions are focused on this sector. With this background, this paper studies energy consumption in city buildings and the CO2 emissions they produce. It only makes use of publicly available data. The analysis is made from the point of view of income per inhabitant, and the results are obtained per inhabitant and household. To facilitate the analysis of the results, an index has been defined. The main contributions of this work are to analyze energy consumption and emissions due to buildings, study them from the point of view of the income of their inhabitants, and consider cities individually. The proposed methodology has been applied to the case of Spain. A total of 145 Spanish cities that have more than 50,000 inhabitants have been studied. The results show that the higher the income, the higher the consumption and emissions. Electricity consumptions are almost inelastic, while those of thermal origin are greatly influenced by the level of income. Regarding CO2 emissions, the percentage of emissions of electrical origin with respect to total emissions is higher than that of thermal origin. In addition, the lower the income, the higher the percentage of emissions of electrical origin.Ministerio de Ciencia e Innovación PID2020-116433RB-I00 (PID2020-116433RB-I00/AEI/10.13039/501100011033