In isolated microgrids, storage systems play a crucial role in maintaining the instantaneous power balance between generation and consumption. Lead-acid batteries are now widely used as storage elements in such systems, and their useful life depends heavily on the operation strategy. This is a serious problem that up to now has limited the sustainability of this type of systems. This article proposes a new philosophy of battery storage energy management for isolated systems based on photovoltaic energy. A dual battery bank is proposed: the first one is responsible for storing energy when renewable sources are available to meet the load demand. The second bank has smaller size and is calculated to meet the needs of daily snapshot balancing and network voltage regulation. The proposed configuration significantly increases the life of the largest bank, reducing the operating and maintenance costs of isolated systems by more than 19 %. Results are reported using data from an isolated microgrid based on photovoltaic solar energy located in Humberto de Campos, Maranhao, Brazil.

There have been an increasing number of government policies and research activities aimed at the exploitation of renewable energy resources to diversify power supply and meet the growing demand for electricity. In the context of Brazil, an example of this is tidal energy, which has a significant potential and is mainly concentrated on the coast of the States of Maranhão, Pará, and Amapá. However, only a few studies have been conducted to evaluate and take advantage of this energy source. One of the works in progress involves the study of a tidal power plant installation at the dam situated at Bacanga. This paper outlines and analyzes the configuration management of a tidal power plant, which is suited to the current physical conditions of the dam and complies with operational and physical constraints. In specific terms, the study takes account the reservoir operating restrictions and available physical space for installing turbines. A recent assessment has been carried out that involves bathymetry, high-resolution photos, and 3-D scanning to evaluate the potential value of the reservoir. This allowed a complete reservoir characterization and the designing of its digital model. Annual studies of optimal operation are reported, as well as factors, such as the technical and economic benefits and drawbacks of the plant.

This article reports the conception and design of a mission critical microgrid to serve a critical infrastructure application, namely, the Alcântara Space Launch Center, a government military facility in Brazil. The assumptions, general characteristics, requirements and particularities arising from the application are established and discussed in detail. High resilience and energy security are required in critical periods of operation, demanding a power supply infrastructure composed of redundant and dispachable sources capable of supporting $n-1$ generation contingencies. Whereas, in the remaining time, economic and environmental aspects take place as main requests. Operation scenarios, on both grid-connected (on-grid) and isolated (off-grid) modes, are formulated as optimization problems and simulations have been performed to analyze these scenarios, which are reported and analyzed here. The off-grid operation, which is clearly more complex, is preferentially addressed, especially in scenarios with contingencies. In this context, the proposed microgrid is conceived to satisfactorily balance requirements such as the economy, pollutant emission reduction, high reliability, resilience and operational security, which are requested by this critical infrastructure application.

A exploração da energia das marés tem se tornado cada vez mais atrativa em diversos aspectos. Alguns projetos maremotrizes sinalizam que outros projetos de geração de energia futuros podem levar em consideração esta alternativa tecnológica. Portanto, neste trabalho são apresentados os princípios básicos de exploração da energia maremotriz, as principais tecnologias utilizadas e princípios de operação de uma usina maremotriz. Além disso, são destacados alguns aspectos importantes, tais como ambientais e econômicos, que estão envolvidos neste tipo de geração e que precisam ser considerados. É feita ainda uma breve avaliação de alguns dos principais projetos já existentes e também são apresentadas algumas das novas tecnologias e as principais tendências em termos de geração maremotriz. Finalmente, são apresentados alguns dos locais mais adequados para a exploração da energia maremotriz no Brasil, bem como algumas das propostas que podem viabilizar tais aproveitamentos.