PTES – A Key Technology for the Future
At the heart of both projects is Pit Thermal Energy Storage (PTES) – a large-scale thermal energy storage technology. PTES facilities are high-capacity storage systems built into the ground, capable of storing thermal energy over extended periods and releasing it when required.
The operating principle is both simple and sustainable:
- Surplus heat (e.g. from renewable energy sources or industrial processes) is stored.
- The heat can be utilised at a later time, for example during the heating season.
- This reduces dependence on fossil fuels.
The storage pond is filled with clean water. Excess heat from PV panels, electric boilers, industrial facilities, or other waste heat sources is fed into the system. The stored heat is then primarily supplied to the district heating network during winter. As a result, the demand for fossil fuels is significantly reduced.
In the context of the energy transition, PTES is a crucial component for decoupling heat supply and demand over time.
Unique – AGRU PP-HTR Lining Systems
A key success factor in the implementation of our PTES projects is the use of AGRU PP-HTR lining systems.
This specially developed formulation has been optimised for the requirements of large-scale thermal energy storage applications, where continuous operating temperatures of up to approximately 95 °C can occur.
Development of this formulation began in 2014 in collaboration with Johannes Kepler University Linz and various research projects. To date, three doctoral theses have been completed on this topic, continuously enhancing the product and establishing the foundation for future standardisation and specification of this application.
Looking Back: Høje Taastrup – Our Flagship Project
With the Høje Taastrup project, we successfully commissioned a high-performance PTES facility in 2023. The system has proven its value in practice and provides valuable operational experience that is now being incorporated into new projects. Key insights include:
- Storage efficiency
- Integration into existing district heating networks
- Long-term operational reliability
Høje Taastrup therefore forms the basis for the further development of the Energy and Heat Transition.
Hyvinkää – The Next Step
The project is currently under construction on the site of a former gravel pit in the Kulomäki area and is likewise based on the PTES concept. Conditions in Finland present both new challenges and opportunities:
- Colder climate and therefore higher demands on thermal energy storage
- Strong reliance on district heating solutions
- Clear focus on sustainable energy supply
Hyvinkää demonstrates how innovative thermal energy storage technologies can be successfully implemented internationally and adapted to different operating conditions.
