Distributed Generation Power System: Applications, Optimization And Analysis Of Barriers Towards Implementation In Ethiopia

Abstract

The interest in integration of distributed generation (DG) systems at the customer and feeder side of distribution networks has been increased throughout the world due to environmental and economic issues which drive DG to be the solution of various problems such as, reliability, ever increasing demand, power loss, pollution and affordability. However, the global share of power generation by this system is comparatively low in the present energy market. Different economic and technical difficulties have been raised as barriers for its low dispersion. To rank and analyze the barriers that hinder these systems dispersion for specific location, their competitiveness in comparison with conventional energy solutions ought to be carefully analyzed and optimized in terms of energy, economy, and the environment. This thesis aims to investigate the impact of renewable DG penetration at the customer and utility side of Ethiopian distribution system. A method to identify the interrelationship among the barriers that affect the development of DG in the country is also proposed. In order to achieve this target, this study is divided into three main parts. In the first part, the techno-economic viability analysis of grid-integrated and islanded photovoltaic (PV)/wind system for industrial and residential loads in four different regions of Ethiopia has been investigated. The load, grid, and meteorological data of the study areas are compiled initially and then the technical, economic and environmental optimization aspects of the proposed system are carried out using PVGIS, PVWatts and HOMER Pro software. Comparison between different possible system configuration and sensitivity analysis are carried out. The results showed that under the considered utility cost of energy (COE), grid-tied PV system are technically, economically, and environmentally viable for all four climate regions. Considering Ethiopian electricity tariff plan incremental (up to 2021/22), the analyzed COE of grid/PV system is around 12% lower than the utility grid tariff. In addition, taking into account the continuous global solar PV cost reduction, the cost of energy of modeled islanded mode of solar PV power systems most likely breaks the grid tariff in the region after 2029 based on the tariff for 2021/22 and well before with expected escalation of the grid tariff on annual basis. iii In the second part, the impact of solar PV integration on power loss and voltage profile of real medium voltage (MV) distribution network is investigated. Capacitor bank insertion has also been considered in the distribution network to compare its impact with DG. The performances of interconnected DG and capacitor in terms of voltage and power losses are analyzed through simulation in Electrical Transient Analyzer Program (ETAP).Voltage sensitivity index (VSI) and genetic algorithm (GA) implemented in ETAP software is utilized to determine the optimal location and sizing of DG and capacitors. From the simulation result, a substantial reduction in active power losses and voltage profile improvement is achieved with a combination of DG and capacitor bank compared to DG and capacitor separately. In addition, it was found that based on the time taken for the analysis, GA technique implemented in ETAP is slightly effective than VSI variational algorithm methods for capacitor sizing. After the technical and economic competitiveness of integrating the selected renewable DG at the customer and MV feeder side are examined, identification and analysis of barriers that hinder the development of solar power in Ethiopia has been addressed as a third part of the study. Extensive literature survey and experts‘ opinions have been used to identify the barriers. Interpretive Structural Modeling (ISM) methodology is adopted to identify the interrelationship among the identified barriers. Matrice d'Impacts Croises-Multipication Applique´ a Classment (MICMAC) analysis has been used to classify the barriers based on dependence and driving power. The results from the model demonstrate that, four barriers related with economics, environmental and behavioral emerge at the top level in ISM structure. A policy barrier appears at the bottom of model and this is considered as the most influential barrier in the country. Moreover, various solutions for relieving the identified barriers have been recommended within the thesis. Better understanding of these barriers could help the concerned stakeholders and policy makers to develop proactive strategies and reinforcement policies to increase the solar power technology in Ethiopia.