Strategy comparison and techno-economic evaluation of a grid-connected photovoltaic-battery system

Abstract

The grid-connected distributed photovoltaic system with battery storage system has gathered growing research interest, while the high system model accuracy, grid and battery interaction, and weather prediction consideration are not widely concerned. In this study, the mathematical model of the photovoltaic battery system is developed, and five operation strategies considering battery charging by the grid and simple weather predictions are proposed and compared under various techno-economic indicators. Results show that the battery state of charge is susceptible to battery pre-charging during valley hours. The self-consumption rate (SCR) and self-sufficiency rate (SSR) can be increased by up to 8.8% and 8.5% respectively via purchasing more grid electricity at valley hours. The system with theoretically perfect weather prediction performs better technically than that of solar radiation data of the day before. Besides, it is proved that system economic performance can be improved effectively through the pre-charging battery by the grid at valley hours, resulting in the 8-17-year payback period of five strategies. Moreover, sensitivity analyses on some key factors are conducted, demonstrating that strategies with higher renewable consumption and less grid injection are more sensitive to battery capacity. The SSR and SCR could increase from 45.6% to 40.9%–70.6% and 65.0% as the battery capacity increases, respectively.