• Energy Research

This paper describes technical solutions to be adopted by Electric Vehicles (EV) battery grid interfaces, in order to get the provision of ancillary services to the grid. The developed solution exploits an EV battery charge control approach based in a grid cooperative response to frequency and/or voltage deviations. To be effective, those cooperative actions must result from both centralized/coordinated commands and local/individual EV charger response to the grid behaviour. In a scenario characterized by a massive deployment of EV, the adoption of such a solution allows an improvement on the power system dynamic behaviour, namely in small island grids.

Abstract Around the world, there is a great concern with the emission of greenhouse gases, creating great interest in turning the energy systems more sustainable. Multi-energy systems are considered as a potential solution to help to this cause and in recent years, it has gained much attention from both research and industry. In this paper, an optimization model is proposed to use the flexibility of multi-energy systems to mitigate the uncertainty associated with wind generation. The differences between the flexibility provided by multi-energy systems and electrical storage systems in the network were studied. The results prove that the flexibility of the multi-energy systems can benefit the system in several aspects and provide insights on which is the best approach to take full advantage of renewable resources even when a high degree of uncertainty is present.

In this paper, a number of possibilities are presented and discussed for the ownership of distributed storage devices (DSD) in a Smart Grid environment. The cases in which the distribution system operator (DSO) has either full control (grid owned storage) or no control whatsoever over the operation of the DSD (independently owned storage) will be differentiated. For each ownership possibility, the technical and regulatory implications are discussed, with analysis and validation of the results being performed on real MV distribution networks, both rural and urban. In order to evaluate each ownership possibility, a number of multi-period optimization models are presented, corresponding to different assumptions in regards to the operation of the DSD. The resulting daily operation strategies are subsequently used as a basis for carrying out distribution reinforcement planning.

There is growing recognition that decarbonisation of existing uses of electricity is only ‘part of the story’ and that closer attention needs to be given to demand for energy in heating or cooling and in transport, and to all the energy vectors and infrastructures that supply the end-use demand. In this respect, concepts such as ‘multi-energy systems’ (MES) have been put forward and are gaining increasing momentum, with the aim of identifying how multiple energy systems that have been traditionally operated, planned and regulated in independent silos can be integrated to improve their collective technical, economic, and environmental performance. This paper addresses the need for modelling of MES which is capable of assessing interactions between different sectors and the energy vectors they are concerned with, so as to bring out the benefits and potential unforeseen or undesired drawbacks arising from energy systems integration. Drivers for MES modelling and the needs of different users of models are discussed, along with some of the practicalities of such modelling, including the choices to be made in respect of spatial and temporal dimensions, what these models might be used to quantify, and how they may be framed mathematically. Examples of existing MES models and tools and their capabilities, as well as of studies in which such models have been used in the authors’ own research, are provided to illustrate the general concepts discussed. Finally, challenges, opportunities and recommendations are summarised for the engagement of modellers in developing a new range of analytical capabilities that are needed to deal with the complexity of MES

Abstract Large scale integration of micro-generation, together with active loads and energy storage devices, under micro-grid and multi micro-grid concepts, requires the adoption of advanced control strategies at different distribution network levels. This paper presents advanced control functionality to be housed at high voltage (HV)/medium voltage (MV) substations and to be used to manage micro-generation, active loads and energy storage, subject to different constraints. Some of these constraints involve inter-temporal relations, such as the ones related with energy storage levels in consecutive time moments. This functionality is specially oriented to deal with stressed MV network operation involving overload and excessive voltage drops situations.

In this paper the existing technical barriers that prevent the accomplishment of a very high wind generation penetration in a power system are presented. Since several countries and regions in Europe are already experiencing such high wind penetration or, as a minimum, planning their grids and operation strategies to cope with wind penetration from a high to a very high level, the solutions already identified for the most common constraints are also identified.

The power distribution grid is centrally managed concerning the requirements of the end-users, however, with the appearance of smart grids, new technologies are arising. Therefore, distributed energy resources, mainly, renewables, energy storage systems, electric mobility, and power quality are viewed as encouraging contributions for improving power management. In these circumstances, this paper presents a power electronics perspective for the power distribution grid, considering innovative features, and including a power quality perception. Throughout the paper are presented relevant concepts for a concrete realization of a smart grid, supported by the integration of power electronics devices as the interface of the mentioned technologies. Aiming to support the innovative power electronics systems for interfacing the mentioned technologies in smart grids, a set of developed power electronics equipment was developed and, along with the paper, are shown and described, supporting the most important contributions of this paper.

THE EUROPEAN ELECTRICITY SYSTEM of the future faces challenges of unprecedented proportions. By 2020, 20% of the European electricity demand will be met by renewable generation while, by 2030, a substantial proportion of the electricity generation would become largely decarbonized. Furthermore, beyond 2030, it is expected that significant segments of the heat and transport sectors will be electrified to meet the targets proposed by the EU governments for greenhouse gas emission reductions of at least 80% in 2050.