Energy Flow Pathway and Economic Impact of Grid-Connected Smart Home PV-Battery Systems Under TOU Tariff

This study evaluates the energy flow and cost-impact performance of a smart home PV-battery system under Thailand's time-of-use (TOU) tariff using one year of measured data. Energy flows were classified into PV direct consumption, battery charging/discharging, grid import, and PV export. Key indicators included the selfconsumption rate (SCR), self-sufficiency rate (SSR), and cost. Results show a high SCR of 0.94, confirming efficient PV utilization, while SSR averaged 0.24 but rose to 0.40 during on-peak hours, contributing most to savings due to high tariffs. Although PV and battery met only one-quarter of demand, they delivered nearly one-third of cost savings, highlighting the disproportionate benefit of on-peak selfsufficiency. High-resolution analysis proved essential, as lower-resolution datasets underestimated transient interactions and distorted savings estimates. These findings underscore the importance of detailed energy flow analysis for accurate technical evaluation and reliable investment planning.