Reliability and Economic Analysis of a Microgrid System: A Case Study of Ifite Community, Nigeria

Date
2021
Authors
Nkado, Franklin
Supervisor
Zamora, Ramon
Item type
Thesis
Degree name
Master of Engineering
Journal Title
Journal ISSN
Volume Title
Publisher
Auckland University of Technology
Abstract

With frequent power outages in Nigeria's Ifite community, which relies only on a diesel generator, solar energy has been recognized as a viable alternative to meet the community's growing energy demand. However, due to photovoltaics’ (PV) high initial cost of installation and intermittent nature, PV systems are not widely used in most Nigerian communities. Therefore, this thesis studies the feasibility of incorporating a Photovoltaic-Battery Energy Storage (PV-BES) into the existing Diesel Generator (DG) system to minimize the community's complete reliance on conventional energy while improving the microgrid's reliability. The study also minimizes the Levelized Cost of Energy (LCOE), Net Present Cost (NPC) and improve the reliability of the proposed microgrid system, which in turn reduces the outage hours and Cost of Load Loss (CLL). The research aims to determine how integrating the PV-BES system to the existing DG significantly affect the reliability and economics of the community’s DG microgrid system. The objective was achieved by utilizing the probability concept in MATLAB to obtain the reliability performance indicators such as the Loss of Load Probability (LOLP), Loss of Load Expectation (LOLE), Expected Energy not Served (EENS). Furthermore, the economic impacts of integrating PV-BES in the existing DG microgrid system were also investigated using MATLAB's fmincon optimization tool. Six scenarios with the same load profile, site irradiation, and diesel generator capacity were used to assess the proposed model's suitability. The proposed system was also modelled in HOMER to verify MATLAB's fmincon optimization tool's result and show the hourly variation of load demand and the generating units in the six scenarios. Additionally, factors such as the PV price, derating factor and azimuth angle effect on the PV energy production were utilized to study their impacts on the cost and operation of the proposed microgrid system. The results show that scenario six provides the optimum solution for the proposed PV-DG-BES with an LCOE of 0.209 $/kWh, total NPC of $614,191 and Initial capital cost of $192,118. The proposed system also improved reliability indices; the LOLP reduced from 2.6 to 0, the LOLE decreased from 84 hr/year to 0 hr/year, the CLL declined from 8,500 $/year to 0 $/year and the EENS from 5,800 kWh/year to 0 kWh/year. To conclude, the analysis results show that scenario six is feasible regardless of the high initial capital cost.

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Keywords
Solar PV , Microgrid system , Battery energy storage system , Levelized cost of energy , Net present cost
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