• Energy Research
• Restricted close
• Open Source close
• Embargo close
• ES close

Artículos en revistas It is shown how a standard nonlinear programming approach can be applied to solve a sophisticated version of the static optimal mix problem in generation planning. The model presented includes technical minima of thermal capacity, detailed operating models of storage-hydro and pumped-hydro units, a realistic model of capital costs for hydro plants, operating reserve and minimum demand constraints, and capacity already in existence. The model formulation is in a format that can be directly handled by the well-known MINOS code and can be efficiently solved. The use of a general-purpose nonlinear optimization program results in a great flexibility, making it possible to modify the model formulation easily or to adapt it to the characteristics of a particular electric system. A realistic application to the Spanish generation system is presented info:eu-repo/semantics/publishedVersion

These 285 documents have been used for the three sections that are part of the results of this article (documents statistics, bibliometric analysis, and literature review statistics). For this purpose, it was necessary to carry out an exhaustive review of the 285 selected documents and to complement this information with the data provided by Scopus. The data-charting process was as follows: the four researchers agreed on the types of data to be extracted, two of them carried out the review while the other two supervised. If any type of data worthy of investigation emerged during the reading, it was discussed, and if appropriate, included, making it an iterative process. For each of the documents, the following variables were collected in a table: author/s, title of the document, year of publication, journal in which it was published, type of document (article or review), number of citations and citations per year, relevance (weighting given by Scopus), DOI, geographical location of researchers, abstract, author keywords and keywords suggested by Scopus, JIF, JCI and H-index information of the journal in which the document is published (with quartiles and percentiles), subject area categories provided by Scopus, territory studied, renewable energy source studied, research technique or methodology used, primary data source used and years collected. In addition, for articles using quantitative techniques, all variables included in each model have been collected.

The world, society and education are constantly evolving, and to respond to these changes, the main governmental institutions have been proposing different global strategies to focus efforts in the same direction. Currently, the United Nations and its 17 Sustainable Development Goals (SDG) have presented a series of indicators that could help to minimise the environmental, economic and social instability we are experiencing. In this sense, Education for Sustainable Development (ESD) has been described as a fundamental factor. Specifically, in previous work, we argued that physical education (PE) could be a good tool to contribute to SDGs. Based on this, no research analysing the voices of Physical Education Teachers (PET) on how this contribution could be made has been identified in previous literature. Therefore, the objectives of this research are: (1) to analyse the voices and opinions of active PETs in terms of the knowledge they have about Sustainable Development (SD); (2) to determine their opinions about the contribution that PE could make to SDGs; and finally, (3) to identify the challenges and limitations of pedagogical action of SD in PE. For this purpose, a qualitative analysis through a semi-structured interview with 41 active PETs was carried out. The main findings will be presented and discussed around four themes: (a) agreement on the concept of sustainability; (b) PE can contribute to the achievement of SDGs; (c) ambiguity in applying SDGs to PE lessons; and (d) teachers’ constraints on how to implement SDGs in PE. It seems to indicate that PETs do not have a multidimensional vision of sustainable development. While they recognise the potential of PE to contribute to SDGs through awareness raising and student learning, they point to its pedagogical and formative constraints as the main barriers to being able to contribute. They pointed to a lack of knowledge on how to do so, guidelines on how to integrate ESD, lack of involvement, shortage of time or resources in school physical education.

Capítulos en libros This paper describes a strategic information platform developed for the German electric utility Eon, to provide historical bidding analysis and medium-term forecasting of the Iberian Electricity Market. This platform, PLAMER, has three main modules: Initialization module, consisting of different sub-modules to define the electrical system structure and to organize the input data of the rest of modules, PLAMER-bids, to read, aggregate and visualize market historical bids and also to prepare them for their future forecasted values, and PLAMER-clearing, for market clearing emulation using forecasted bids. PLAMER-clearing models the Iberian market based on a bid clearing mechanism with an inherent market splitting procedure. This market splitting is built with a bi-nodal simplification, one node representing the Spanish System and the other the Portuguese one. Both are simply connected by a unique equivalent interconnection line. The medium term clearing model uses a generation portfolio per generation company in terms of technologies, for supplying monthly demand for different load levels, and labour and non-labour periods. Some technical constraints, such as minimum outputs and pumping energy balance, are also taking into account. The mathematical problem of PLAMER-clearing is a quadratic programming model solved using GAMS language and CPLEX optimizer. Finally, a real Iberian case study is detailed and some market splitting outputs are analyzed. info:eu-repo/semantics/publishedVersion

It is now environmentally desirable and legally mandatory to add renewable fuels such as ethanol or ethyl tert-butyl ether to gasoline. However, biofuels affect, among other properties, the distillation curve of gasoline, which is subject to strict regulations. This work presents a simple mathematical model capable of accurately predicting the influence that the addition of these oxygenates has on the distillation curve. In order to address this issue, it is essential to find a simple mathematical correlation between the boiling temperatures of the hydrocarbons present in gasoline and the properties (boiling temperature and volume or molar concentration of ethanol) of the corresponding azeotropic mixtures formed with ethanol. Power functions have been assumed to model the temperature composition diagrams of the vapour-liquid equilibrium. Experimental data previously published by these and other authors have been used to fit and validate the model. The results provided by the mathematical model can be of great interest to understand the process of fuel evaporation in spark-ignition engines or the adjustment of distillation cuts in refineries, in order to comply with the regulations, in terms of the distillation curve, after adding ethanol or ethyl tert-butyl ether.

Artículos en revistas There has been total unanimity about the vital importance of reliability of supply since the beginning of the electricity sector deregulation process. This paper describes the procedure proposed by Pérez-Arriaga et al. [2005. White paper for the reform of the regulatory scheme of the power generation in Spain. For the Ministry of Industry, Tourism and Trade of Spain (in Spanish)] to improve upon the current scheme to guarantee a reasonable reserve margin, the capacity payment mechanism. This alternative design introduces improvements aimed at guaranteeing at least a minimum capacity reserve margin, as well as at providing a strong incentive for generating units to be available when needed, namely, in situations when supply is likely to be insufficient to meet the total demand. info:eu-repo/semantics/publishedVersion

Capítulos en libros This paper presents a general method to convert State feedback controllers to damp power system electromechanical oscillations to the standard structure formed by an Automatic Voltage Regulator (AVR) and a Power System Stabilizer (PSS). The proposed conversion method is based on least squares fitting in the frequency domain. info:eu-repo/semantics/publishedVersion

It is widely accepted that medium-term generation planning can be advantageously modeled through market equilibrium representation. There exist several methods to define and solve this kind of equilibrium in a deterministic way. Medium-term planning is strongly affected by uncertainty in market and system conditions; thus, extensions of these models are commonly required. The main variables that should be considered as subject to uncertainty include hydro conditions, demand, generating units' failures, and fuel prices. This paper presents a model to represent a medium-term operation of the electrical market that introduces this uncertainty in the formulation in a natural and practical way. Utilities are explicitly considered to be maximizing their expected profits, and biddings are represented by means of a conjectural variation. Market equilibrium conditions are introduced by means of the optimality conditions of a problem, which has a structure that strongly resembles classical optimization of hydrothermal coordination. A tree-based representation to include stochastic variables and a model based on it are introduced. This approach to market representation provides three main advantages: Robust decisions are obtained; technical constraints are included in the problem in a natural way, additionally obtaining dual information; and large-size problems representing real systems in detail can be addressed.