Optimal design of microgrid based on hybrid energy systems for selected areas in Iraq

Since 1991, Iraq suffers from a long-term and rampant electricity shortage. The electricity is available only for a few hours per day in most of the cities. Moreover, many of the rural areas are still undeveloped and not connected to the grid. These issues affect the everyday life of the Iraqi people. The current power system in Iraq uses fossil fuels which cause serious environmental issues besides their depletion at a fast rate. Nowadays, there is unprecedented global interest in the utilization of renewable energy sources which offer environmentally friendly and sustainable energy. However, in contrary to the fossil fuel systems, most of the renewable energy sources have the issue of being intermittent energy sources depending on weather conditions, which negatively affects the production of energy for a substantial proportion of the year. This issue can be overcome by using a hybrid energy system that can produce better reliability as compared to the single-source energy system. This thesis presents the design and analysis of different hybrid energy systems to supply electricity for different areas in Iraq. A sensitivity analysis is carried out to investigate the impacts of change in critical parameters on the system performance. Different control strategies such as load following strategy, cycle-charging strategy, combined dispatch strategy and modified dispatch strategy are considered. Moreover, the research examines the performance of a combined on/off-grid hybrid energy system using on/off hybrid inverter and investigates how this system can improve the performance of a common on-grid system in the cities which are unable to serve the load during the electricity blackouts. HOMER and MATLAB have been used as tools for the optimization analysis by considering the techno-economic and environmental performance of the systems. The analysis reveals that the use of off-grid hybrid energy systems in remote areas in Iraq is an efficient option and hence becomes increasingly competitive with fossil fuel. Furthermore, the results demonstrate that the selection of a suitable energy management strategy affects the optimum results dramatically by controlling the flow of energy and deciding the priority of each component in the system. Moreover, the combined on/off-grid hybrid energy system is found to be an attractive option for cities in Iraq to overcome the limitations of the usual on-grid system.