Hybrid Renewable-based Reliable and Cost-effective Rural Electrification in Southern Africa

The national electrification rate of South Africa is about 75%, however only 55% of rural areas have access to electricity compared to 88% in urban areas [1]. Off grid renewable energy systems (HRES) are becoming promising alternatives to those regions and can replace conventional power systems such as diesel generators or grid power. They incorporate two or more renewable energy systems which complement each other making the system more efficient and reliable. In addition to the HRES, a battery storage system and a diesel generator (DG) can be added for uninterrupted power supply [2][3] when neither renewable energy power sources can meet the load demand. However, the components of the system must be sized optimally to provide a cost effective and reliable solution. Therefore, a techno-economic analysis comprising of various hybrid configurations is required. In this paper, eleven HRES systems comprising of solar PV, wind turbines, diesel generator and battery storage were designed using HOMER for the electrification of two rural villages in Sub Saharan Africa namely Ncera and Boipuso. Optimization was carried out using HOMER and based on the results, a Solar/Wind/Diesel Generator/ Battery system was selected as the most cost-effective solution for both villages. The optimal system for Ncera consists of a 7.80 kW rated PV system, a 20-kW rated wind turbine, a 50-kW convertor, a 44-kW dw capable of supplying electricity with a LCOE of $0.173/kWh. The optimal system capacities for Boipuso include a 70.3 kW rated PV system, two 20kW rated wind turbines, a 100-kW rated diesel generator 102 strings of batteries with a 75kW rated converter and can supply electricity at a LCOE of $0.210/kWh.