Design and Analysis of an Off-grid Hybrid Renewable Energy System to Supply Electricity in Small Industries: A Case of Tanzania

Abstract

"The off-grid hybrid power systems were attracting to supply electricity to small companies and interprices in different aspects like reliability, sustainability and environmental protections. Hybrid power system with various combinations based on renewable sources could be applied simultaneously to cater energy in the form employed in an off-gird supporting with battery storage and diesel generator as backup systems. In this thesis wind turbine, photovoltaic, battery bank and converter sytem have been simulated and optimized for the Bellaview Fresh Fruit Processing Industry Ltd in Rombo, Kilimanjaro region in Tanzania. Electric load demand of 1600 kWh/day, peak load of 184 kW was involved during optimization of the power system. Well known HOMER modeling tool have been used to design the off-grid system. Wind and solar energy are considered as primary sources to supply electricity directly to the load and to charge battery bank when excess generation is happened however in peak demand. The Industry's load has been suggested for running machines, lighting, water pumping, etc. During the design of this power system setup, the simulation and optimization were done based on the electricity load, climatic data sources, economics of the power components and other parameters in which the net present cost (NPC) has to be minimized to select an economic feasible power system. Moreover other parameters like capacity shortage, renewable fraction, excess of electricity, cost of electricity (COE), diesel fuel consumption was also considered to check the technical capability so as to select a system that is sound in techno-economic aspects. Some approaches were used as comparison measurements to select one power system from the selected options giving due merit to one of the measuring instruments (low cost of energy). HOMER simulation result displayed the most economical feasible system sorted by NPC from top to down, the prime system ranked first has renewable fraction of 100% containing of 8 unit wind turbines with 100 kW each rating power, 189 kW photovoltaic panel, 487 unit batteries, and 142 kW converter. Sensitivity analysis was also performed for the system, different sensitivity cases were used such as; 2 values of primary loads, 3 cases of diesel prices and 2 cases of minimum renewable fractions."