ATES Vienna – Vienna Aquifer Thermal Energy Storage

Half of the non-renewable share of total final energy consumption in Austria corresponds to the heating and cooling sector. District heating and cooling systems, though highly efficient, suffer from a temporal mismatch between the supply of renewable energy sources and the demand from consumers. Therefore, to achieve a fully decarbonised heating and cooling sector, a major development in large-scale seasonal thermal energy storage must be made.

From a technological point of view, only large-scale pit thermal energy storages and/or aquifer thermal energy storages (ATES) can be considered for this purpose. Aquifers can serve as a promising, cost-effective alternative to pit storages with their biggest advantage being an extremely low surface area requirement and therefore highly suitable for urban areas. High temperature ATES (HT-ATES) typically refers to ATES with storage temperatures > 40°C. To obtain these temperatures, one must drill deep down to a minimum of 1-3km. In practice there are very few HT-ATES currently in operation, with the majority of existing aquifers focussing on low temperature, shallow applications.

The Vienna ATES project aims to identify and characterise available aquifer resources for integration into the Austrian district heating sector as well as providing assessment tools to estimate their suitability for HT-ATES applications. Based on this analysis, a detailed technical concept for the first pilot ATES in the Vienna area will be developed, considering the utilization of existing hydrocarbon wells and new drilled wells. The feasibility study will be completed by a holistic socio-economic and regulatory impact analysis as well as a detailed techno-economic and environmental evaluation for various technical options.