In the past period, work has been done on the further planning of the 7 demonstrators, on the development of components, processes and numerical simulations and on the assessment of pit thermal energy storage (PTES) regarding economy, environment and social acceptance.
Demonstrator
Like all PTES developments, the TREASURE demonstrators have met delays in the past 18 months. The delays are caused by challenges in the acquiring of land, in the permitting processes or in completing the financing of the project, or in combinations of these. In internal workshops, the group has addressed the challenges in the screening phase and in the planning/permitting phase. Possible solutions to the challenges were presented and discussed and will be used by the demonstrator owners to clear barriers. Also, a workshop was held with the 17 satellite PTES initiatives to exchange the status of the developments and to discuss challenges and barriers.
Components
The first design of a prototype cover, consisting of glass foam in a metal sheet encasement was made. The design is aimed at withstanding higher storage water temperatures, up to 100 degrees Celsius, and to be water vapour tight at these temperatures. An inventory was made of the methods to reinforce the sloped side walls of the PTES, to arrive at steeper walls, creating the advantage of a smaller top cover area, leading to possible cost reductions. For soil mechanics, a literature study has been performed, a test plan for physical and mechanical characterisation of soil samples was made, and a measurement set-up was developed to determine soil characteristics at higher temperatures.
Processes and simulations
Different fault detection methods, based on Artificial Intelligence, were investigated. Two basic geometries of PTES were defined in an adapted BIM (Building Information Model) to serve as test objects for the development of the dedicated Storage-BIM (S-BIM) environment. Monitoring data from the Høje Taastrup storage operation in 2024 has been quality controlled and published in an open-access journal. For the system simulation including PTES, a workflow, tools and KPIs to accurately model and evaluate the PTES behaviour have been established, resulting in three public deliverables. The European and national subsidy schemes for funding the investment and/or operation of PTES have been investigated and the results will be made available in a coming publication.
Economic, environmental and social acceptance assessment
Life cycle assessment (LCA) models were developed for a tank thermal storage in Linz, not in the project, and the Høje-Taastrup monitoring demonstrator. These models serve to test and validate the models for the demonstration cases. Regarding social acceptance, a literature review was conducted to identify existing research and theoretical frameworks relevant to our application field, and an initial internal workshop was conducted that served to introduce the scope of social acceptance within the project and initiate stakeholder engagement.
