Optimal planning and sizing of microgrid cluster for performance enhancement

Access to electricity is a key indicator of a country's development. In developing nations like Ethiopia, this metric is particularly crucial for assessing progress. Currently, about 45.8% of Ethiopia's population lacks access to electricity, with rural areas experiencing even higher rates, reaching 57.2%. The Southern Nations, Nationalities, and People's (SNNP) region faces the greatest challenge, with 62.1% of its population lacking electricity. Ethiopia aims to achieve universal electricity access by 2030, and microgrid (MG) development is expected to play a pivotal role in meeting this goal. This study employs a multi-tier framework (MTF) to categorize village households based on electricity access, considering factors like income level and willingness to pay, to support the MG development process. Three villages-Toba, Koza, and Womba-in the SNNP region were selected for optimal MG sizing. Sensitivity variables such as global horizontal irradiance (GHI) variation, photovoltaic (PV) and battery prices, battery usage limits, and capacity shortage levels were analyzed for their impact on net present cost (NPC), initial capital cost, and cost of energy (COE) using HOMER Pro software. For example, in the Toba MG, increasing the capacity shortage from 0 to 10% reduced the COE from 0.1195 $/kWh to 0.09104 $/kWh, a 23.82% decrease. Additionally, fluctuations in PV and battery prices had a direct impact on the system's NPC. The study also explored the impact of clustering the microgrids by interconnecting the three individual systems and conducting a techno-economic analysis. The comparison between standalone MG operation and clustered microgrids revealed that, despite the added cost of interconnection, the benefits in terms of technological, economic, and reliable operation of the clustered system were comparable to standalone microgrids. Finally, a feasibility study was conducted for the potential grid extension of the Toba MG, which is located 130 km from the nearest substation in Sawla.