Power to heat: Opportunity of flexibility services provided by building energy systems

Buildings play a crucial role in global electricity consumption, but their function is evolving. Rather than merely consuming energy, buildings have the potential to become energy producers through participating in flexibility services, which involve demand response and distributed energy supplies. However, the new technological and societal challenges that arise from temporal and spatial changes on both supply and demand sides make building services increasingly complex. This paper presents an opportunity for flexibility services offered by building energy systems via power-to-heat technology and discusses four key aspects: quantitative indicators based on thermal inertia, model predictive control for building flexibility, flexible system optimization for smart buildings, and applications of flexible services. Thermal inertia is a crucial factor that transcends technical constraints and serves as a bridge between the demand and supply sides. Demand-side response and data-driven cogeneration under model predictive control are essential for managing building flexibility. In addition, flexible system optimization is achieved through the combination of demand-side trading and disturbed system optimization. Applications of flexible services represent a combination of demand-side trading and disturbed system optimization in the fields of engineering and sociology. Finally, the paper explores the challenges, as well as the potential and models of building flexibility services technologies, including features that can facilitate automated operational decision-making on both the demand and supply sides.