The project aims to store excess renewable energy produced in summer for use in winter, thus reducing dependence on natural gas. This pit thermal energy storage (PTES) system uses water or mineral materials to accumulate heat. This initiative could transform district heating networks by increasing their share of renewable energy and optimizing their management. Inter-seasonal storage is particularly relevant for district heating networks such as the one in Pau. In summer, when renewable energy production is in excess, the surplus can be stored and used in winter to meet peak consumption. This not only maximizes the use of renewable energy such as geothermal energy but also reduces operational costs related to the use of fossil fuels.
The TREASURE Program Framework
TREASURE, funded by the European Union to the tune of €9,894,688.40, aims to demonstrate the effectiveness of thermal storage systems to decarbonise district heating networks. The project includes 15 initiatives in 5 countries, with a consortium of 24 partners. The first French phase, composed of technical, economic and environmental studies, is expected to last one year. This phase aims to assess the feasibility of an operational demonstrator. TREASURE’s ambition is to bridge the gap between research and practice to phase out fossil fuel dependence in district heating networks, in line with the objectives of the European Green Deal. The project focuses on improving the design, development procedures and operation of thermal storage systems for better integration into existing heating networks.
Key Partners
Three main French players are involved in this project:
– **Pau Béarn Pyrénées Urban Community**: manager of a 44 km heat network, supplying 11,000 homes.
– **ENGIE Solutions**: network operator, using local renewable sources, notably hydrogen.
– **Newheat**: specialist in renewable heat storage.
The Pau Béarn Pyrénées Urban Community recently inaugurated its heating network, which includes 169 substations and supplies 208 subscribers. This network is supplied 50% by the Lescar energy recovery plant, 25% by the biomass plant located in Lons and 25% by the gas plant of the University of Pau and Pays de l’Adour. The TREASURE project aims to further increase the share of renewable energies in this energy mix.
Implications et Perspectives
Hugues Defreville, President and co-founder of Newheat, highlights the opportunity of this technology to improve energy efficiency. He emphasizes that heat storage solutions are mature and can be deployed to replace a significant portion of the fossil fuels used. Pit storage would make it possible to recover excess heat produced in summer to meet winter needs, providing a solution to seasonal variations in renewable energy production. François Bayrou, President of the Pau Béarn Pyrénées Urban Community, notes the importance of meeting new energy needs while improving the coverage rate of renewable energies beyond the current 75%. The community, always a pioneer in energy innovation, sees this study as an opportunity to move towards a sustainable energy transition. Cédric Maisonneuve, Director of the Territoire Sud ENGIE Solutions design office, emphasizes the objective of defining the key parameters for a virtuous and stable storage project. He specifies that ENGIE Solutions is exploring all technologies that can contribute to the extension and greening of district heating networks, making this European project particularly relevant. The study of this innovative thermal storage system marks an important step towards better management of district heating networks and could serve as a model for other European cities. The success of this initiative could accelerate the deployment of 100% renewable district heating networks, thus reducing dependence on fossil fuels and contributing to European climate objectives.
