Udayasoorian Kaaviya Priya, Ramalingam Senthil
Buildings are central to the global energy transition, contributing significantly to energy use and emissions while offering major opportunities for decarbonization and resilience. With rising electrification, renewable integration, and climate risks, energy storage has become essential for decoupling supply and demand, enhancing flexibility, and enabling advanced control. This review delivers a thorough, building-centric evaluation of energy storage technologies that enhance resilience in building energy systems. It covers electrical, thermal, and chemical storage solutions, including batteries, sensible and latent thermal energy storage, and hydrogen-based systems. It assesses their roles across a range of timescales, from short-term operational flexibility to long-term and seasonal resilience. A primary finding is that no single storage technology can deliver comprehensive energy resilience. Instead, robust performance results from integrated, multi-storage approaches tailored to specific climatic, economic, and social factors. Thermal energy storage, particularly systems based on phase change materials, provides cost-effective, demand-side resilience with minimal grid impact, while electrical storage offers rapid response, peak shaving, and grid support. Hydrogen-based systems supply long-term and seasonal storage, working alongside batteries and thermal storage, especially in grid-constrained or remote areas. This review also highlights the critical role of digitalization, artificial intelligence, and advanced control methods in maximizing the benefits of resilience. Finally, it identifies key research gaps, including insufficient long-term field validation, the absence of standardized resilience metrics, economic and regulatory challenges, and inadequate consideration of social and equity aspects.