Energy Flow and Cost Saving Impact of a Smart Home PV-Battery System under Time-of-Use Tariff

This paper proposes an analytical study on the energy flow and cost-saving impact of a smart home photovoltaic (PV) system integrated with battery storage under a Time-of-Use (TOU) electricity tariff scheme. Data was collected over 21 months from a smart home energy management system (EMS) in Thailand. The study investigates the contribution of PV, battery, and grid energy, which are categorized by on-peak and off-peak periods, to consider in different costs corresponding to a time of energy usage. The result reveals that energy flow strategies controlled by energy management, particularly during on-peak hours, significantly reduce electricity bills. The system achieved a 38% total cost saving, with 52% of on-peak energy demand offset by solar and battery supply. The correlation between final yield (Yf) and cost saving showed a strong linear relationship (R² = 0.9279). Results highlight the critical role of energy flow optimization in enhancing the economic benefits of PV-battery systems under TOU tariffs.