Integration of large-scale thermal energy storage in the wider energy system

District heating is a pivotal technology to decarbonise heating systems, offering an efficient pathway to significantly reduce greenhouse gas emissions through centralised provision of heat from renewable and waste energy sources. Additionally, it can provide essential flexibility to the wider energy system, accommodating variable energy loads, integrating diverse energy sources effectively and reacting to grid and market signals. Large-scale Thermal Energy Storage (LTES), which is significantly cheaper than other forms of large energy storage, is essential to provide flexibility in accommodating variable resources as well as the capability to react to grid and market signals and thus provide additional income. While the general case of adding LTES is clear, there is significant risk in the design and operation of the storage as well as its integration with the wider energy system.