A Comprehensive Review of Building-to-Grid Interaction

Rapid electrification and the rising penetration of variable renewable energy are fundamentally increasing the volatility of global power systems. In this context, activating demand-side flexibility has emerged as a critical strategy to maintain grid stability. Buildings, accounting for approximately 30% of global energy demand, offer a massive and controllable resource for such flexibility. By leveraging adjustable end-users, inherent thermal mass, and distributed energy resources, modern buildings can transform from passive consumers into active grid-interactive hubs. To navigate this paradigm shift, this review formulates a holistic framework for collaborative building-to-grid energy governance. It systematically examines how individual building flexibility can be quantified, aggregated, and coordinated into dispatchable resources to support grid operation across multiple timescales. The review further analyzes the evolution of control strategies, highlighting a clear shift from standalone building optimization toward multi-building hierarchical coordination. Recognizing that the practical implementation of these strategies depends on more than control algorithms alone, the review also examines the cyber-physical foundations required for deployment, including hardware infrastructure, communication protocols, semantic data models, and hardware-in-the-loop validation. In addition, it discusses the broader enabling conditions for large-scale adoption, with particular attention to policy support, market mechanisms, and standardization frameworks. By clarifying the technical, cyber-physical, and regulatory interdependencies of building-to-grid systems, this review provides an integrated reference for advancing flexible, resilient, and low-carbon energy systems.