Technical and economical evaluation of grid-connected renewable power generation system for a residential urban area

This research investigates the techno-economic assessment of a hybrid grid system of solar and wind power for a residual urban area in Khvaf town located in the eastern part of Iran. The temperature profiles of a 10-year period are gathered based on the existing solar and wind condition data. Simulation, economical and technical evaluations of this hybrid system are studied with the aid of HOMER software. To reach a proper independent structure from the total net present cost and energy cost viewpoints, thousands of cases were studied. Change of the factor investing on PV panels together with the amount of the sun radiance as well as change of the investment factor of wind turbines with the consideration of wind velocity and sun radiance on the system layout are studied and discussed. The initial investment is 440 thousand dollars and the contribution portion of the renewable energies is 84% for the case containing four wind turbines and a power grid system (optimal system). This optimal system returns the investment over a 4-year period which is very economically attractive. The optimal system for the case with a low mean wind speed of 3 m/s is preferred to involve 13-kW photovoltaic (PV) panels, one-wind turbine and a 10-kW converter with a power grid network. Results shown that when the cost of the PV panel is 0.6 times higher than the current cost, a system consisting 4-wind turbines connected to the grid network is still the optimal system. In addition, a sensitivity analysis is made on the load demand of the hybrid system and the renewable energy resource. As a result, the most influential variables on the performance of the system are identified in this research. Based on the economic and technical evaluation, establishing a hybrid grid system for a residential urban area is perfectly reasonable with the investment return during the fourth year of a 25-year project lifetime. Also, among the systems studied, a system with four wind turbines and a power grid system is chosen as an optimal system due to the fact that the region has favorable potential for wind energy.