• Energy Research

Artículos en revistas A smart city is a sustainable and efficient urban centre that provides a high quality of life to its inhabitants through optimal management of its resources. Energy management is one of the most demanding issues within such urban centres owing to the complexity of the energy systems and their vital role. Therefore, significant attention and effort need to be dedicated to this problem. Modelling and simulation are the major tools commonly used to assess the technological and policy impacts of smart solutions, as well as to plan the best ways of shifting from current cities to smarter ones. This paper reviews energy-related work on planning and operation models within the smart city by classifying their scope into five main intervention areas: generation, storage, infrastructure, facilities, and transport. More-complex urban energy models integrating more than one intervention area are also reviewed, outlining their advantages and limitations, existing trends and challenges, and some relevant applications. Lastly, a methodology for developing an improved energy model in the smart-city context is proposed, along with some additional final recommendations. info:eu-repo/semantics/publishedVersion

This paper proposes a linear programming problem to find the optimal planning and operation of aggregated distributed energy resources (DER), managed by an aggregator that participates in the day-ahead wholesale electricity market as a price-maker agent. The proposed model analyzes the impact of the size of the aggregated resources and gives the optimal planning and management of DER systems, and the corresponding energy transactions in the wholesale day-ahead market. The results suggest that when the aggregated resources are large enough, DER systems can achieve up to 32% extra economic benefits depending on the market share, compared with a business-as-usual approach (not implementing DER systems). info:eu-repo/semantics/draft

Capítulos en libros The smart city is a sustainable and efficient urban center that provides high quality of life to its inhabitants with an optimal management of its resources, where clean and cost effective energy generation is a key issue. Under this setting, distributed generation can provide an adequate tool to deal with energy reliability and to successfully implement renewable sources; nevertheless, selection and scaling of energy systems, considering location, is not a trivial task. Frequently, the stakeholders analyze only one or two "popular" generation systems, and then calculate the output and return of investment in a simplified and approximated approach. This practice could lead the stakeholder to an inadequate technology mix. To tackle this problem, this paper reviews and models most common energy sources for distributed generation in a smart city context. Then, a technical economic analysis is developed for 2 cases, a household and a district, considering not only renewable sources but also efficient non-renewable technologies. The results of the numerical analysis help to assess the more adequate generation systems for a given application, energetic demand, and geographical characteristics. A well-developed analysis is essential for a better understanding of the available technologies and their synergies; as a result, the investors can choose the appropriate solutions, maximizing overall benefits. info:eu-repo/semantics/publishedVersion

Balancing markets will become more and more relevant with the increased volatility in the electricity system due to the increase in the renewable quota. New policies are paving the way for customers flexibility participation as demand response in reserve products. This paper contributes with an assessment of the impact of demand response participation in the reserve market when planning the electricity system’s operation and investment in new technologies. The model used has been conveniently upgraded and a set of scenarios have been raised to conduct the analysis. The residential and services sectors' consumption for heating, cooling, hot water, and electric vehicles are considered as sources of flexibility. Each one has their own modeling to represent their nature. Main findings show that demand response receives and offers more benefits for the system on the wholesale market than in balancing services, although their participation in them is quite relevant. This is due to the decrease in firm capacity investment needs thanks to reducing systems’ peak technologies and the decrease of spillages from renewables. Additionally, increasing demand response percentages in the systems lead to cost reduction. However, there is a limitation associated with an increase of CO2 emissions due to the usage of existing polluting technologies to avoid investments in storages. Finally, flexibility providers are compared to determine their flexible capabilities.

Artículos en revistas Deployment of Distributed Energy Resources (DER) is already a reality for electricity supply and the debate whether distributed generation is going to replace almost totally or partially the current centralized generation paradigm is currently in place. Technical and economic advantages of DER have been addressed in the literature although regulation has also played a central role in DER deployment. This paper aims at contributing to that debate. Firstly, the advantages of both paradigms are reviewed and the cost recovery problem of the existing centralized related stranded costs discussed. Secondly, an optimization model , formulated to specifically address the discussion comparing both configuration paradigms. Main factors affecting the debate are identified and represented in the model: investment and operation costs, flexibility system requirements, demand response capabilities, building thermal demands, network investments and losses, and access-fee design, among others. Thirdly, a realistic case study, based on Spain, is presented and some qualitative conclusions extracted. Such kind of model is useful to undertake country specific studies either to perform sensitivity analysis revealing the relevance of the factors involved and the direct and indirect relationships among technologies, or to analyze the more efficient system configuration and align regulatory decisions towards it. info:eu-repo/semantics/publishedVersion

Artículos en revistas This paper analyzes the optimal planning and operation of aggregated distributed energy resources (DER) with participation in the electricity market. Aggregators manage their portfolio of resources in order to obtain the maximum benefit from the grid, while participating in the day-ahead wholesale electricity market. The goal of this paper is to propose a model for aggregated DER systems planning, considering its participation in the electricity market and its impact on the market price. The results are the optimal planning and management of DER systems, and the appropriate energy transactions for the aggregator in the wholesale day-ahead market according to the size of its aggregated resources. A price-maker approach based on representing the market competitors with residual demand curves is followed, and the impact on the price is assessed to help in the decision of using price-maker or price-taker approaches depending on the size of the aggregated resources. A deterministic programming problem with two case studies (the average scenario and the most likely scenario from the stochastic ones), and a stochastic one with a case study to account for the market uncertainty are described. For both models, market scenarios have been built from historical data of the Spanish system. The results suggest that when the aggregated resources have enough size to follow a price-maker approach and the uncertainty of the markets is considered in the planning process, the DER systems can achieve up to 50% extra economic benefits, depending on the market share, compared with a non-aggregated business-as-usual approach (not implementing DER systems). info:eu-repo/semantics/publishedVersion

Artículos en revistas Recently, driven by the increasing concern regarding electricity supply resiliency, literature has paid attention to Microgrids (MGs) and their technical performance to ensure a reliable supply, although few papers have addressed the economic behavior of isolated MGs. Recent European Projects have launched the proposal of a local market based approach to operate the isolated MG. One of the main concerns of such an approach is whether the small size of such markets may lead to strategic behaviors, although it depends on the number and size of local market agents. This paper presents a mathematical modeling, formulated as a Mix Complementarity Problem (MCP), of the economic planning and operation of isolated MGs, able to represent the impact of agent s strategic behavior through the explicit consideration of conjectures. Although identifying the value of such conjectures for each particular MG is out of scope of this paper, a case study is conducted to analyze the impact on investments and local prices. Besides, it includes a temperature model for buildings, able to consider its thermal inertia and allowing prosumers to take advantage of its Demand Response (DR) capabilities regarding its thermal and electricity needs. The paper conducts different case studies to illustrate its impact. info:eu-repo/semantics/publishedVersion

Artículos en revistas Operation of distributed energy resources and resilience related problems are becoming of most importance in the pursuit for a more sustainable electricity delivery. Microgrids (MGs) could contribute significantly to both issues and may play an important role in the new decentralized paradigm of power systems. This paper proposes a hierarchical organizational scheme of MGs with a clear distinction of the Microgrid, Nanogrid and Picogrid concepts, and addresses a detailed technical literature review to identify and classify MGs main features and design alternatives. Definitions; descriptions of MGs, Nanogrids, Picogrids; operation modes; business models and communication protocols are dispersed in the literature. In order to gather clearly all the existing information, this review has been organized according to four functional layers, inspired by the ones commonly used in Smart Grid architecture description. For each one and whenever possible, the paper classifies the outcomes of the review in a table kind of format that helps summarizing the different MGs' options. Regarding the first layer, the paper describes the different physical devices involved in MGs, such as generators, converters, electric vehicles (EV) and energy storage systems (DS) and the DC levels that are being discussed. For the second layer the paper addresses a review of the communication protocols currently used or proposed. Then, the intelligence layer is analyzed concerning any decision making issue related to operation and planning of the MGs as well as any other aspect that may be relevant for taking advantage of MGs potentiality. In the last layer, the paper reviews different business models adapted to a future where MGs will be deployed. Finally, the paper ends with an exhaustive review of the practical MG experiences in place worldwide, classified according to the issues presented previously, and a brief discussion of the key points to be addressed in the MGs deployment. info:eu-repo/semantics/publishedVersion