Abstract
The continuous proliferation of distributed generation is leading end users to look for new tools that help to design hybrid electrical energy systems (HEES). Thus, this work proposes a novel approach for optimal planning of HEES, which comprises the optimization of the type and capacity of distributed generation connected to the end user. The main objective is to minimize the project's total cost, considering the net metering scheme. To this end, the bioinspired meta-heuristic artificial immune system is proposed to optimally determine the number and type of photovoltaic panels. In addition, a nonlinear programming model is proposed to optimize the diesel generator and BESS capacity, considering the energy supply to the consumer by the HEES and the main distribution grid. Case studies involving commercial and residential customers in Brazil are introduced considering the normative resolutions from ANEEL, the Brazilian Regulatory Agency. Comparative analyses are made concerning an exhaustive search procedure and the commercial software Homer Pro, designed to optimize the operation of HEES systems. An important conclusion is that the proposed approach is as effective as the cutting-edge tools, with reasonable computational effort.

Abstract
This work performs a comparative analysis of battery energy storage system (BESS) participation in the multi-services electricity market, considering the optimal operating cost and better profitability for the BESS portfolios. A comparison of the application of these portfolios in different market conditions is proposed: (i) energy-only market, (ii) reserve-only market, (iii) sequential energy and reserve market, and (vi) joint energy and reserve market. For each BESS portfolio, hourly strategies for buying and selling offers are proposed, to maximize the revenue, accounting for the expected load and generation variations in the grid. The analysis of the BESS strategies is carried out through a case study based on actual generation data, where operating costs and BESS flexibility are assessed. One conclusion is that, even though, BESS makes a profit by participating in single markets, the best strategy is to participate in both energy and reserve markets, especially in the presence of a joint energy and reserve market model.

Abstract
Traditional models of power systems are undergoing a restructuring process, stimulated by the growing deployment of renewable energy sources, making them more decentralized and progressively increasing the focus on the consumer. New arrangements are being explored, allowing consumers to play a more active role in energy systems, highlighting the concept of consumer-centric markets. This work presents an optimization model that considers the insertion of the battery energy storage system (BESS) in the concept of community energy markets. This model aims to increase the community income and includes the degradation of BESS, also evaluating different arrangements of BESS in the community markets. In the investigated scenarios, discussions about the feasibility of inserting BESS through the analysis of social welfare (SW) and fairness indicators were carried out. With the results, it was possible to observe that there are structures that are more advantageous from the perspective of the communities and others from the perspective of the members of the communities, bringing some insights into the different impacts of a BESS in an energy community.

Abstract
Distributed energy resources have been increasingly integrated into electrical grids. Consequently, electricity markets are expected to undergo changes and become more complex. However, while there are many scientific publications on the topic, a broader discussion is still necessary. Therefore, a systematic literature review on electricity markets in the context of distributed energy resources integration was conducted in this paper to present in-depth discussions on the topic, along with shedding light on current perspectives, the most relevant sources, authors, papers, countries, metrics, and indexes. The software R and its open-source tool Bibliometrix were used to perform the systematic literature review based on the widely recognized databases Web of Science and Scopus, which led to a total of 1685 articles after removing duplicates. The results demonstrate that demand response, renewable energy, uncertainty, optimization, and smart grid are the most-used keywords. By assessing highly impactful articles on the theme, emphasis on energy storage systems becomes clear compared to distributed generation and electric vehicles. However, electric vehicles draw attention in terms of citations. Furthermore, multi-level stochastic programming is the most-applied methodology among highly impactful articles. Due to the relevance of the demand response keyword, this paper also conducts a specific review on the topic aligned with electricity markets and distributed energy resources (296 articles). The results demonstrate that virtually all high-impact publications on the topic address day-ahead or real-time pricing. Based on the literature found, this paper presents a discussion on the main challenges and future perspectives related to the field. The complexity of electrical power systems and electricity markets is increasing substantially according to what this study found. Distributed generation development is already advanced, while energy storage systems and electric vehicles are limited in many countries. Peer-to-peer electricity trading and virtual power plant are newer concepts that are currently incipient, and DR programs showcase an intermediate stage of evolution. A particular lack of research on social issues is verified, and also a lack of all-encompassing studies that address multiple interconnected topics, which should be better addressed in the future. The in-depth assessment carried out in this paper is expected to be of high value to researchers and policy-makers and facilitate future research on the topic.

Abstract
The power and energy sector transition into decentralized and distributed models brings a set of challenges that need to be overcome. Among them is consumer empowerment, which requires secure economic transactions and reliable system operation. Thus, new technologies and procedures such as blockchain have gained prominence, due to their reliability and privacy-preserving capabilities. These characteristics are essential for the proliferation of energy community markets. Therefore, this paper provides an overview of blockchain technology applicability to consumer-centric electricity markets, highlighting existing projects and initiatives. Additionally, key enablers and barriers to blockchain deployment in local electricity markets are discussed, followed by a roadmap for the comprehensive adoption of such technology.

Abstract