Flexibility Provision From Urban Buildings to Low-Carbon Power Systems: Quantification, Aggregation and System Integration

Achieving net-zero emissions requires a comprehensive transformation of energy infrastructure. The expansion of intermittent renewable generation together with increased demand, for example, from electric vehicles and heat pumps, exerts significant stress on grid stability and reliability, making power system flexibility essential for maintaining power and energy balance and enhancing system resilience. Urban buildings, with integrated heating, cooling, on-site generation, storage and flexible demand, constitute a substantial, cost-effective flexibility resource. In this paper, building flexibility is first defined and its physical drivers are identified. Quantification methods at the individual building scale, including physics-based simulations, machine-learning models and hybrid approaches supported by recent experiments, are then surveyed. Aggregation frameworks that include Virtual Power Plants and Virtual Energy Storage Systems are examined, comparing centralised, decentralised and hierarchical control strategies, ICT requirements and market-integration pathways. The participation of aggregated building flexibility in wholesale markets and its provision of distribution-level services are analysed. Enabling measures such as dynamic tariffs, demand-response programmes, smart-readiness indicators and relevant standards are critically evaluated. Finally, future research needs in integration, standardisation and policy development are outlined. That leveraging urban building flexibility may be crucial for developing a reliable, cost-effective, low-carbon power system is suggested by our analysis.