Depletion-aware intelligence for solar–wind–battery systems: Machine learning pathways for robust sizing, safe dispatch, and battery health management

Battery depletion limits the reliability of solar photovoltaic (PV)–wind–battery systems when renewable variability, converter dynamics and electrified loads reduce usable battery energy or reserve. Here, depletion denotes insufficient deliverable energy or reserve to satisfy load, reliability, ride-through or recovery requirements. State-of-charge (SOC)-floor violations and reserve exhaustion are direct signatures; unmet load is a consequence, whereas deep discharge, cycling and ageing are interacting drivers. Unlike reviews centred separately on state estimation, degradation, sizing or energy management, this review develops an author-derived, literature-grounded ten-stage lifecycle spanning architecture, commissioning, surplus capture, routine cycling, transient shocks, SOC-floor binding, outage depletion, ageing, control drift and functional end-of-life. A systematic review of 102 peer-reviewed English-language studies published during 2010–2025 covers PV–battery energy storage systems (PV–BESS), wind-turbine–BESS (WT–BESS), PV–WT–BESS, grid-connected and direct-current (DC) microgrids, including outage and electric-vehicle (EV) applications. Studies were coded by machine-learning (ML) family, battery function, depletion stage, chemistry, metric and validation credibility, with multi-label assignment for multifunctional studies. Evidence is concentrated in surrogate-assisted sizing and forecast-coupled dispatch, while commissioning, shock events, controller drift and cross-stage validation remain underdeveloped. Safe and chance-constrained learning can protect SOC margins, but adaptability under compound, out-of-distribution extremes is not yet established. Chemistry is frequently unreported, restricting transferability. The resulting stage–mechanism–ML–chemistry–credibility framework links algorithmic performance to constraint satisfaction, resilience, ageing and service continuity, providing a reproducible basis for comparing depletion-mitigation claims.