Minimization of Simple Payback Time through Reactive Power Injection & kVA Billing in MW Scale Solar PV Power Plant

MW scale renewable power generation through solar PV plants is promoted strongly to curtail down the CO2 emission in power sector. However, high installation cost of solar power plant results into a long simple payback time due to limited utilization factor of solar PV plant. This paper provides a methodology to improve the utilization factor of solar PV plant through injection of reactive power to the utility grid during no Sun hours. It is proposed that kVA billing of total energy injected to utility grid would effectively improve the utilization and bring down the simple payback time. The design and implementation of a 2MW scale solar power plant, consisting of DC-DC converters connected to active front-end converters is studied in the paper. The system involves LCL filter for better power quality and feeds power to 33 kV grid through a step-up transformer. An analysis is presented in the paper to suggest the reduction in simple payback time due to injection of reactive power in different proportions. The penalty imposed by utility due to poor power factor is also considered in the simple pay back time computation. A suitable proportion is proposed for minimization of simple payback time for the MW scale solar PV power plant. MATLAB/Simulink based model of the solar power plant is developed and performance of the same is presented during various operating conditions.