Design of Home Electricity Supply System Using Solar PV and Its Integration to the National Grid: A Case Study of Masaka Village

Abstract

In spite of the way that non-renewable energy sources are found in relatively small number of places, they are consumed worldwide. On the other hand, the sustainable power source is accessible everywhere throughout the world; however, it is so far used just by little a portion of the total world population. Currently, because of an increased awareness of the environmental impact of fossil fuels and advancement in renewable energy technology, there is a rise in the use of renewable energy as an alternate source of energy. Due to a rapid increase in household biomass energy consumption which has been occurring recently in Rwanda particularly in urban and semiurban households due to the energy crisis in Rwanda, solar energy is promoted and widely adopted at the domestic level. This insufficient electricity is affecting industrial growth and projected markets extension in the country. Therefore, different measures must be applied to ensure the future national growth projections. This work presents a study that examined the possibility of supplying electricity to Masaka village households by using a grid-connected solar PV system. Rwanda has a geographical advantage by virtue to its position approximately two degrees below the equator and in the region where the sufficient solar radiation for PV generation system can be accurately foretasted. Data for solar insolation and domestic load from the case study was collected and then analysed so as to design a typical solar photo-voltaic system. Information gathered have demonstrated that Masaka village receives a monthly average solar insolation of 4.8 kWh/m2/day for the most time of the year. The selected middle-class family has the average peak power of 5.93 kWp while the total daily energy consumption is 8.3 kWh. RETScreen Expert package was used to size and simulate the photo-voltaic system suitable for the selected house. Considering the daily energy consumption for the household and different loses, a 3 kW PV system was sized where the surplus electricity during off-peak demand could be exported to the grid and be imported when there is a low production for the system. In order to reach this project's goal, a cost-benefit analysis was performed to determine if the investment would be financially worthwhile. The results reveal that solar energy is viable in this selected village with an initial investment of $ 11,489 and a payback period of 8.1years. The designed system will be capable of satisfying the needs of the selected household and injecting the surplus power to the grid.