Feasibility Study of a Standalone Solar-Wind-Genset with Energy Management System for Rural Electrification in Ethiopia

Abstract

It is known that, Ethiopian Electric power utility company uses extension of grids and installation of diesel generator as option for electrification of rural villages. But, grid extension to such area is not practically feasible as these locations are geographically isolated, sparsely populated and have a very low demands. The only use of diesel generators has also harmful effects on environment in addition to higher cost fuel, maintenance and operation. In this thesis, feasibility of solar-wind-genset has been simulated and optimized using HOMER software for the rural community of Nura Hase among the Bosat district, East Shoa, Oromia of Ethiopia. The primary (households, school, healthy centers and churches loads) energy demand of the community is 905Kwh/day with 264Kw peak load and the deferrable (water pumping loads) energy demand of 7.6Kwh/day with 750w peak load was involved during optimal design of hybrid power system. It is also compared the cost of hybrid system with cost required to electrify the villages by extending the grid such that, the net present cost of extending the grid is equal to the net present cost of stand-alone system at the point 9.94km which is breakeven distance. Farther away from the grid, the stand-alone system is optimal and nearer to the grid, grid extension is optimal. Moreover, programmable logic controller (PLC) based energy management system has been incorporated to automate the off-grid system. Accordingly ,solar and wind energy are considered as primary sources to supply electricity directly to the loads and to charge battery bank when there are excess solar and wind energy generation. However, in peak load times diesel generator could also be engaged. The load has been suggested for primary loads(house hold, healthy center,school,churches) and deferrable loads(water pumping and milling).The integration of the hybrid system is to electrify residential houses and their surrounding in order to reduce the need for fossil fuel leading to an increase in the sustainability of the power supply. The study shows that a 50Kw solar, 10*250Kw wind turbines, 55Kw diesel generator and 175 units of 6CS25P batteries with best optimum hybrid system configuration with cost of energy 0.111$/Kwh and net present cost 336,530$ is required for the communities.