Seasonal thermal energy storage as a complementary technology: Case study insights from Denmark and The Netherlands

Seasonal thermal energy storage (STES) has potential to act as an enabling technology in the transition to sustainable and low carbon energy systems. It is a relatively mature technology, providing a reliable and large-scale solution to seasonal variations in energy supply and demand where it has been deployed at scale. In practice, however, there remains minimal deployment of STES internationally, with only a small number of countries being exceptions. Here, we analyse STES development in two of these exceptions: the Netherlands and Denmark, and we consider the relevance of the Dutch and Danish STES experiences for other countries, such as the UK, where STES is currently marginal. In explaining the diffusion of STES in leading countries, and its limited uptake elsewhere, we pay attention to energy system context by investigating the complementarities – or misalignments – between different parts of energy systems which have influenced STES deployment. The contribution arising from our mainly qualitative and historical analysis is to demonstrate the importance of contextual factors such as national policy and complementarities between technical and social factors in influencing STES deployment. This approach, we argue, can complement and enrich engineering and economic perspectives on STES.