Abstract
This work describes an economic analysis of the inclusion of pumped storage in a small island system that has abundant renewable energy available but that at times cannot accept all of this power because of limits imposed by security criteria. The question of whether or how much pumped storage to include is addressed by formulating a linear programming optimization problem. The stochastic nature of load and renewable production is addressed using scenarios developed through fuzzy clustering. Both the unit capacity in MW and the reservoir storage capacity in MWh are optimized, and optimal operating strategies for the scenarios are produced. Results showed that including pumped storage can be an effective means of allowing larger penetration of intermittent renewable energy sources, improving both the dynamic security and the economic operation of a test system. Including the dynamic security criteria in the economic question of dimensioning the pumped storage unit proved to make a significant difference in the optimal pumped storage capacity.

Abstract
This paper addresses the allocation of electrical losses in distribution networks with embedded generation, in a liberalized environment. The nonlinear nature of the issue, the loss changes due to voltage variation and, specially, the contribution of embedded generation to loss variation are considered. The proposed method is based on tracing the real and imaginary parts of the currents and has two steps. First, the losses in the distribution network, in the absence of embedded generation, are allocated to the consumers (or their providers). Second, the variations in the losses that result from the influence of embedded generation are allocated to the generatorsi These variations are a measure of the avoided or added costs related to losses. In the allocation process, made in a branch basis, both real and reactive powers are considered. The methodology presented in this paper can be used to evaluate embedded generation incentives or to design tariffs for the use of the distribution network.

Abstract
This paper presents a Multicriteria Decision Aid methodology for planning energy storage and sustainable mobility, in an isolated system. The objective of this research is to enhance the sustainability of the analyzed case study (São Miguel Island), by comparing a set of alternatives for energy storage and sustainable mobility. The alternatives characterization and evaluation is made through the calculation of meaningful attributes, namely: carbon emissions, overall costs and reliability. An analysis of the most interesting alternatives is also performed. © 2011 IEEE.

Abstract
Recognizing the benefit that one can get by exploiting the Micro-Grid (MG) concept, as an active part of the Low Voltage (LV) network comprising several micro-generation (mu G) sources, controllable loads and storage devices, is a key issue towards the MG concept deployment. Furthermore, the MG concept is extended into Multi-Micro Grid (MMG) concept, identifying the benefits that can be obtained at Medium Voltage (MV) level. The main idea behind this research is to show what one gains and what one looses by setting up the MG concept. Therefore, the benefits reported, are evaluated through a cost-benefit approach by modeling the problem as a multi-attribute problem using several Decision-Aid (DA) techniques to capture different Decision Maker (DM) preference structures.

Abstract
The emergence of micro-generation as a technically sound alternative has lead, in recent times, to the concept of microgrid, a network of LV consumers and producers able to export electric energy in some circumstances and also to work in a isolated way in emergency situations. Research work about the organization of microgrids, control devices, functionalities and other technical and economic aspects is presently being carried out, in order to establish a consistent technical framework to support the concept. Among other aspects, the effect of microgrids in the reliability of the distribution network has been pointed out as an important advantage, due to the ability of isolated operation in emergency situations. In order to address this topic, the present paper identifies the situations where the existence of a microgrid may reduce the interruption rate and time and thus improve the reliability indices of the distribution network. The relevant expressions necessary to quantify the reliability are also presented. An illustrative example is included, where the global influence of the microgrid in reliability is commented.

Abstract
The need of fast algorithms for radial distribution networks that take advantage of their particular structure has been increasing, namely due to the use of genetic algorithms and meta-heuristics for optimization in planning and operation. In this paper, a new method for power flow calculation in radial networks is presented. It uses an iterative process along the branches, in a way similar to other methods, but the main idea is very different from previous approaches, since it is based on the exact power flow solution for a single branch and also because it provides a complete solution (not only voltage magnitudes). The method is fast and robust for different types of networks and loads, including heavy loads. The paper includes the theoretical derivation of the method, an illustration example and tests with benchmarking networks. © 2003 IEEE.