Design exploration and network integration of Underground Thermal Energy Storage for Cities (UTES4City)

The project develops and evaluates large-scale underground thermal energy storage concepts in St. Gallen – Hybrid Tank‑Borehole and Cavern storage – to integrate low‑carbon heat into district heating networks and enable scalable, replicable UTES solutions for Switzerland.

Key data

Description

Switzerland’s ambitious decarbonization goals are driving a rapid expansion of district heating networks (DHNs). Seasonal thermal energy storage is essential to enable the integration of intermittent low-carbon heat sources – such as waste heat, and geothermal – into DHNs.

This project addresses the challenges of implementing large-scale underground thermal energy storage using the city of St. Gallen as a representative case. It explores two novel concepts: Hybrid Tank-Borehole Thermal Energy Storage and Cavern Thermal Energy Storage. The former combines borehole and buried tank systems to provide both seasonal and short-term flexibility, while the latter explores scalable vertical shaft configurations.

The project includes spatial analysis, dynamic simulations, construction feasibility, and integration into district heating networks. It aims to lay the foundation of feasible and replicable UTES solutions enabling broader adoption and supporting strategic energy planning across Switzerland.