Search

Abstract: Africa is the poorest continent in the world and this poverty is linked to the lack of access to energy of its population. A big part of inhabitants live in rural zones where the lack of energy and in particular of electricity is still more flagrant. The aim of the Micro-grids project was to promote the electrification of rural regions of Senegal by the installation of micro-grids with high content of renewable energies. This paper presents some results of this project. Surveys have been carried out in three regions of Senegal to study the needs of electrical energy of non-electrified rural villages'' households. These surveys have led to the estimation of electricity needs of the concerned households. The potential in renewable energies of the three regions has also been examined. It has been concluded that the solar energy potential is excellent while the wind energy potential can be interesting in some specific sites. The biomass could also be an efficient source if livestock farming was properly managed in the future. Moreover, many events have been carried out in the three regions to analyse the obstacles for the development of micro-grids in the Senegalese energy context, and to establish suitable solutions to overcome these obstacles. The results presented in this paper have been used to design a rural electrification kit which is described in another paper. Now the Micro-grids'' consortium hopes to set up a new project to apply the designed kit on some rural non-electrified villages. [Copyright &y& Elsevier]

Abstract: A high penetration rate of the Renewable Energy Sources (RES) can create stability, reliability and power quality problems in the main electrical grid. The microgrid should be a feasible alternative to solve these issues. As it is a weak electrical grid, the microgrid is very sensitive to any variation and consequently an Energy Storage System (ESS) is necessary to reduce their effect. A microgrid needs an ESS with high energy and power densities, but none of the currently available storage technologies satisfies both requirements at the same time. Consequently, it is necessary to associate more than one storage technology creating a Hybrid Energy Storage System (HESS). The objective of this work is to compare by means of simulations three different topologies that are used to control a HESS formed by a SuperCapacitor (SC) bank and a Vanadium Redox Battery (VRB). The compared topologies are the parallel active topology, the floating topology and the Three-Level Neutral Point Clamped (3LNPC) converter topology. The analysed microgrid is formed by the mentioned HESS and different renewable energy sources. This microgrid is interconnected to a weak grid based on a Diesel Generator (DG). Two case studies have been analysed: the effect of the RES while the microgrid is connected to the weak grid and the effect of the disconnection of the microgrid from the weak grid. The different topologies are compared analysing their capability of facing the mentioned variations, their power losses and their Total Harmonic Distortion (THD). The Matlab/Simulink software and the SimPowerSystems toolbox have been used to carry out the simulations. [Copyright &y& Elsevier]

Abstract: Senegal is one of the less developed countries in the world (position 158 in a list of 174 countries). 85% of its rural population does not have access to electricity and there''s no doubt that this is an important barrier for socio-economic development. In this context, the project Microgrids aims at contributing to solve this problem. This project is part of the Intelligent Energy – Europe Programme supported by the European Commission. Its objective is the promotion and dissemination of the use of micro-grids with high content of Renewable Energy Sources (RES) for the electrification of villages far away from the grid in Senegal. One of the results of the project was the analysis of rural electrification needs, which is described in another paper [Camblong H, Sarr J, Niang AT, Curea O, Alzola JA, Sylla EH, Santos M. Microgrids project, part 1: analysis of rural electrification with high content of renewable energy sources in Senegal. Renewable Energy, submitted for publication.]. This paper presents the design of an electrification kit based on the information provided by that analysis [Analyse des besoins locaux pour l''électrification de zones rurales au Sénégal. Technical report of Microgrids project; 2007. Available from: http://www.microgrids-eie.com.]. After identifying necessary previous conditions for the sustainability of any electrification project, a methodology is proposed for the design of the electrification kit. This methodology is applied to a typical village and results are extended to differently sized villages in the areas of Thies, Fatick and Kaolack. Economic considerations are also included to establish the relationship between electrification costs and paying capability of the communities. Now the Microgrids'' consortium hopes to set-up a new project to apply the designed kit on some rural non-electrified villages. [Copyright &y& Elsevier]

Abstract: The increasing use of distributed generators, which are mainly based on renewable sources, can create several issues in the operation of the electric grid. The microgrid is being analysed as a solution to the integration in the grid of the renewable sources at a high penetration level in a controlled way. The storage systems play a vital role in order to keep the energy and power balance of the microgrid. Due to the technical limitations of the currently available storage systems, it is necessary to use more than one storage technology to satisfy the requirements of the microgrid application. This work validates in simulations and experimentally the use of a Three-Level Neutral Point Clamped converter to control the power flow of a hybrid storage system formed by a SuperCapacitor and a Vanadium Redox Battery. The operation of the system is validated in two case studies in the experimental platform installed in ESTIA. The experimental results prove the validity of the proposed system as well as the designed control algorithm. The good agreement among experimental and simulation results also validates the simulation model, that can therefore be used to analyse the operation of the system in different case studies. [Copyright &y& Elsevier]