The Linz District Heating Forum 2026 highlighted the role of large-scale thermal storage and 'heat highways' in decarbonising heating. With strong input from the TREASURE project, experts presented technologies, case studies, and strategies shaping future district heating systems.
(Note: Opinions in the articles are of the authors only and do not necessarily reflect the opinion of the European Union)
This article reports on key insights from the Linz District Heating Forum 2026, focusing on large-scale thermal energy storage and district heating innovation. It highlights contributions from the TREASURE project partners and leading experts across Europe. The event demonstrated how collaboration and technology can accelerate the transition to climate-neutral heating.
On 17–18 March 2026, leading researchers, industry experts, and city representatives gathered in Linz for the first Linz District Heating Forum, hosted by Johannes Kepler University Linz’s Energieinstitut. The inaugural edition focused on 'Heat Highways', large-scale thermal energy storage (LTES), and industrial cooperation, key pillars for transforming district heating into a backbone of Europe’s decarbonised energy system.
From the start, the forum positioned district heating not as a legacy infrastructure, but as a rapidly evolving system integrating renewable energy, waste heat, and digital optimisation. In his opening remarks, Gabriele Pesce from Euroheat & Power highlighted the urgency of this transition: two-thirds of fossil gas in the EU is still used for heating and cooling. District heating and cooling (DHC), already 39% electrified and sourcing 34% of heat from waste streams, is emerging as a central solution to phase out fossil fuels in buildings and industry.
Building on this systemic perspective, Simon Moser from Energieinstitut (JKU) emphasised the importance of cross-sector cooperation. His presentation, 'Energy cooperation: thinking beyond company borders', underlined that decarbonisation requires coordinated action across industries, municipalities, and research institutions. Learning from best practices and maintaining open dialogue among stakeholders, he argued, is essential to scale up innovation.
This collaborative spirit was echoed throughout the forum, particularly in contributions from the TREASURE project, which featured prominently across sessions. The project aims to advance large-scale thermal storage solutions and establish new standards for their deployment in district heating systems.
Introducing the project, Wim van Helden from AEE INTEC outlined the diversity of LTES technologies, including:
The project’s ambition is to set a new benchmark for PTES systems, particularly in terms of scalability, performance, and integration into district heating networks.
Further expanding on this, Geoffroy Gauthier, from PlanEnergi highlighted that LTES systems operate at GWh-scale capacities and are critical for balancing seasonal heat demand. He emphasised the role of advanced simulation tools, which support decision-making across all project stages and are being actively applied to TREASURE demonstrators.
The forum also showcased concrete implementations. Marieluise Pöschko-Reinweber, from Wien Energie, presented Vienna’s Scale-UP project, aimed to make the city climate-neutral by 2040 and reduce emissions by one-third by 2030. She demonstrated how large-scale thermal storage enhances system flexibility and reduces the need for additional generation capacity, such as gas boilers or heat pumps.
Meanwhile, Uwe Hempfling from Hansestadt Rostock introduced a feasibility study for a PTES system of up to 500,000 m³. The project aims to harness abundant local waste heat, provide affordable district heating, and strengthen regional energy resilience. However, he also highlighted significant administrative challenges, including permitting processes and regulatory uncertainties. This underscores the need for supportive policy frameworks.
Beyond deployment, several sessions addressed optimisation and sustainability. Stefan Puschnigg, from Energieinstitut (JKU), presented cost analyses using the Levelised Cost of Heat for storage systems (LCoHss), enabling comparison of technologies over their full lifecycle. He stressed that seasonal storage and waste heat recovery will be central to future district heating systems.
Complementing this, Helene Mihatsch from Energieinstitut (JKU) introduced a Life Cycle Assessment (LCA) framework for thermal storage. Using a functional unit of 1 MWh of delivered heat, her work evaluates environmental impacts across the entire lifecycle, from raw material extraction to disposal, ensuring that overall sustainability benefits are maintained.
Practical insights from TREASURE demonstrations further enriched the discussion. Jianhua Fan, from the Technical University of Denmark, presented monitoring results from the 70,000 m³ PTES system in Høje Taastrup, highlighting advanced data analysis techniques, including AI-based methods, for predicting heat flows and detecting system faults.
On the engineering side, Andreas Hawel from Aalborg CSP shared lessons learned from PTES lid design, addressing key challenges related to durability, insulation, and installation. These are critical factors for long-term system performance.
Meanwhile, Anja Gahleitner from Energieinstitut (JKU) highlighted the non-market benefits of thermal storage, including system resilience and energy security, while ongoing surveys aim to quantify these impacts better. Michal Klauda (FENIX TNT) has opened the discussion on stakeholder perspectives on LTES.
Across all sessions, a clear narrative emerged: district heating is undergoing a profound transformation. It is evolving from a centralised heat supply system into a flexible, multi-source energy network, capable of integrating renewable energy, waste heat, and digital technologies.
Large-scale thermal storage, particularly PTES, has emerged as a cornerstone technology, enabling seasonal balancing, reducing reliance on fossil fuels, and increasing system efficiency. At the same time, projects like TREASURE demonstrate that collaboration between research, industry, and municipalities is essential to overcome technical, economic, and regulatory barriers.
The Linz District Heating Forum emphasised the increasing link between research, policy, and practical implementation in Europe’s heating transition. With significant input from the TREASURE project, the event went beyond theoretical discussions, showcasing specific technologies, real-world case studies, and the practical actions needed to deploy large-scale solutions.
As Europe moves toward climate-neutral buildings and cities, the message from Linz was unmistakable: large-scale thermal storage and intelligent district heating are no longer optional innovations, but essential infrastructure. The discussions made it clear that the transition is already underway. What remains to be determined is the speed at which these solutions can be deployed at scale.
