Abstract

The integration of behind-the-meter battery storage with rooftop photovoltaic systems under time-of-use tariffs creates a tractable residential energy management problem requiring balanced dispatch decisions across tariff periods. This study develops a deterministic, forecast-free rule-based dispatch algorithm with intra-period look-ahead for a grid-connected residential photovoltaic-battery system under Sri Lanka’s 2026 time-of-use tariff. Household demand is modelled using the RECON-SL smart meter dataset, while the algorithm operates at 15-minute resolution without requiring real-time forecasting or historical runtime data. Two lithium iron phosphate battery configurations are evaluated alongside a 5 kW rooftop photovoltaic array under 81 weather-sequence scenarios representing sunny, cloudy, and rainy conditions. Results demonstrate stable and economically robust performance across both favourable and adverse operating conditions. Financial viability is assessed under varying state-of-charge constraints and export tariffs, showing that investment feasibility depends strongly on the approved peak export tariff and battery operating strategy, with implications for residential energy management and distributed energy resource scheduling.