Helena Martín

This paper provides a comprehensive overview of policies and incentives aimed at promoting high-temperature heat pumps (HTHPs) globally. It examines the various strategies employed by different countries to encourage the adoption of HTHPs, highlighting both the opportunities and the barriers encountered in these efforts. The analysis includes a review of financial incentives, regulatory measures, and technological initiatives designed to facilitate the integration of HTHPs into industrial applications. By describing different approaches across regions, this paper identifies best practices and potential pitfalls, offering a nuanced understanding of how different policy frameworks impact the deployment of HTHPs. Additionally, this paper explores the technological challenges that influence the effectiveness of these policies. The findings underscore the critical role of supportive policies in overcoming technical and economic barriers, ultimately fostering the widespread use of HTHPs as a viable solution for reducing industrial emissions and advancing global decarbonization goals. Furthermore, utilizing electricity from renewable energy sources (RESs), HTHPs can also contribute to grid stability by reducing electricity peaks. This aspect enhances the integration of RESs into the energy mix, creating a more resilient grid and optimizing energy consumption patterns in industrial applications.

Combined Heat and Power (CHP) has been identified by the EU as a powerful resource capable of making substantial contributions to energy savings and reducing GHG emissions. Spain’s effort to promote CHP has been prolific since the 1980s. In this regard, there have been various Laws, Royal Decrees (RDs) and European Union (EU) Directives addressed to reach the national objectives set for the CHP sector. Despite these attempts, the evolution and growth of installed CHP capacity has been irregular, compared to other technologies. Likewise, the academic treatment of the Spanish CHP evolution has not deserved the same attention as other technologies such as wind, photovoltaic and thermal solar systems. As a result, this article is aimed at providing a comprehensive overview of the regulatory frameworks applied to the Spanish CHP sector and analysing the reasons behind the variable evolution of the installed CHP capacity. The study covers the legislative context from 1980 to 2020, describing the evolution during both the pre-liberalization and liberalization periods, highlighting the modifications in economic policies that affected self-producers and the so-called Special Regime (SR) for CHP, and examining the challenges faced during the cost containment measures that followed. The manuscript finds and explains the connection between the regulatory framework and the evolution of installed CHP capacity in Spain. Likewise, the connection between the industrial situation and the promotion of CHP, as well as the influence of the Spanish Electricity Sector (SES)’s liberalization on the CHP sector are also pointed out. The paper intends to provide valuable insights for CHP experts and policymakers by showcasing the importance of aligning regulatory measures with the objectives of energy efficiency. It also serves as a reference for countries in various stages of promoting CHP, and provides evidence for the importance of stable energy-policy control mechanisms.

El gran atractivo del modelo estándar del motor de inducción en ejes dq con parámetros constantes reside en su relativa simplicidad, por lo que generalmente se toma como base para la predicción de su conducta dinámica. No obstante, durante transitorios exigentes y en determinadas condiciones de operación, este modelo se revela claramente inadecuado para representar el comportamiento de la máquina.Para paliar este hecho, numerosos esfuerzos se han efectuado para incluir en el modelo del motor efectos tales como el de ranura profunda o la saturación magnética, así como otros fenómenos de segundo orden. No obstante, el enorme incremento en complejidad experimetado por el modelo desincentiva su utilización.En la presente tesis se explora la bondad de determinados modelos simplificados con inclusión del efecto de ranura profunda y la saturación magnética del flujo principal, evaluando bajo qué condiciones su utilización ofrece garantías.Concretamente, se muestra la necesidad del empleo de modelos con inclusión del efecto de ranura profunda para la determinación del tiempo de operación estable del motor trifásico de inducción ante huecos de tensión, evidenciando cómo aun los modelos de orden reducido, mas de doble jaula, predicen resultados acordes con los datos de catálogo suministrados por el fabricante, cometido en el que falla el modelo estándar de jaula sencilla.En lo tocante al modelado de la saturación magnética, se justifica la divergencia en los resultados obtenidos a partir de los modelos con y sin intersaturación cuando estos son formulados en función de determinados conjuntos de variables de estado, a partir de la evaluación de los pesos relativos de los distintos términos que marcan la diferencia entre ambos tipos de modelos, contribuyendo así a clarificar un punto que ha sido objeto de controversia en la literatura especializada. Se efectúa, así mismo, un estudio detallado sobre las implicaciones del uso de parámetros y magnitudes referidos en los modelos con y sin intersaturación, evaluando para qué conjuntos de variables de estado su utilización resulta ventajosa.En suma, queda puesto de manifiesto que haciendo uso de determinados recursos simplificativos, es posible modelar con garantías efectos que en muchas ocasiones son obviados en los modelos para evitar la excesiva complejidad que su inclusión aporta, pero que en aplicaciones concretas resultan esenciales para representar adecuadamente el comportamiento real del motor.

As renewable energy sources and microgrids have developed, the need to use a transversal approach for dealing with issues on the design and energy management of these assets is clear. Although renewable energy sources and microgrids are used within the electricity sector in a significant number of countries, the technical and scientific literature often dismisses the effects that in-force regulatory frameworks have on this type of assets. This Special Issue aims to enlighten readers on the relationship between the electricity sector’s regulatory frameworks and microgrids, providing clear evidence on the need to consider regulatory constraints in their design and energy management.

Editorial: Technologies and policies for decarbonisation of the industrial and transport sectors

The prediction and characterization of solar irradiation relies mostly on either the use of complex models or on complicated mathematical techniques, such as artificial neural network (ANN)-based algorithms. This mathematical complexity might hamper their use by businesses and project developers when assessing the solar resource. In this study, a simple but comprehensive methodology for characterizing the solar resource for a project is presented. It is based on the determination of the best probability distribution function (PDF) of the solar irradiation for a specific location, assuming that the knowledge of statistical techniques may be more widely extended than other more complex mathematical methods. The presented methodology was tested on 23 cities across Morocco, given the high interest in solar investments in the country. As a result, a new database for solar irradiation values depending on historical data is provided for Morocco. The results show the great existing variety of PDFs for the solar irradiation data at the different months and cities, which demonstrates the need for undertaking a proper characterization of the irradiation when the assessment of solar energy projects is involved. When it is simply needed to embed the radiation uncertainty in the analysis, as is the case of the techno-economic valuation of solar energy assets, the presented methodology can reach this objective with much less complexity and less demanding input data. Moreover, its application is not limited to solar resource assessment, but can also be easily used in other fields, such as meteorology and climate change studies.

Renewable energy is increasingly mobilizing more investment around the globe. However, there has been little attention to evaluating economic and regulatory (E&R) uncertainties, despite their enormous impact on the project cashflows. Consequently, this review analyzes, classifies, and discusses 130 articles dealing with the design of renewable energy projects under E&R uncertainties. After performing a survey and identifying the selected manuscripts, and the few previous reviews on the matter, the following innovative categorization is designed: sources of uncertainty, uncertainty characterization methods, problem formulations, solution methods, and regulatory frameworks. The classification reveals that electricity price is the most considered source of uncertainty, often alone, despite the existence of six other equally influential groups of E&R uncertainties. In addition, real options and optimization arise as the two main approaches researchers use to solve problems in energy system design. Subsequently, the following aspects of interest are discussed in depth: how modeling can be improved, which are the most influential variables, and potential lines of research. Conclusions show the necessity of modeling E&R uncertainties with currently underrepresented methods, suggest several policy recommendations, and encourage the integration of prevailing approaches.