Optimum Design of Grid Connected Hybrid System of Solar PV and Run-of-the-River Hydropower Plant for Power Shortage Mitigation – Case Study: Rugezi Run-of-the-River Hydropower Plant in Northern Province of Rwanda

Abstract

As the global energy demand is increasing rapidly all over the world, hybrid systems of renewable energy sources provide reliable, clean and cost-effective electrical energy. The hybrid system formed by solar PV and hydro power plant is the best choice in Rwanda the country with high potential of hydro resources and solar irradiance. In this research the hydro logical data with the corresponding power produced in different three consecutive years 2020,2021,2022 were collected at Rugezi hydropower plant which really helped to identify the existed highest power shortage, this highest power shortage was 1850kW and occurred in August 2020 and this is the basis of the designed solar PV power plant. The minimum power produced at Rugezi hydro power plant corresponding to that highest power shortage was 822kW. The designed solar PV power plant to mitigate the power shortage was combined with Rugezi hydro power plant so that the power generated by that formed hybrid system is always equivalent to the installed capacity of Rugezi hydro power plant. During this design the Musebeya  site nearest water intake of Rugezi hydro power plant was selected as the best site for solar PV power plant installation ,the yearly average solar irradiance of the selected site is 4.71kWh/day  .The installed capacity of the designed solar PV is 2000kWp and the output of the inverter is 1900kWac which is capable  to mitigate  the power shortage of 1850kWac.The PVsyst 7.3 software was used to design solar PV  power plant and Homer pro was used to combine solar PV and hydro power plant so that they form  hybrid system  whereas Matlab software was used for linear programming of the hybrid system. Based on the hybrid system optimization it was found that one generating unit of Rugezi run of the river hydro power plant must be in operation and works in parallel with solar power plant during dry seasons for 1850kWac power shortage mitigation