Storing heat should be a no-brainer. It makes sense to generate that heat when it’s cheap and efficient to do so, then store it for later use.
The technologies that offer this – known as thermal energy storage – are developing all the time.
Heat pumps, for example are great for thermal energy storage, because they can use excess electricity (e.g. from solar or wind during peak production) to heat water or other materials efficiently. This allows the heat to be stored, for example in hot water or underground tanks.
A recent webinar organised by a coalition of EU-funded projects dived into the role of thermal energy storage in building decarbonisation.
These are BEST-STORAGE, HYSTORE, ECHO and THUMBS-UP, with the last two including EHPA as a partner.
The event, moderated by Emilia Pisani from the Swedish research institute RISE, welcomed attendees and set the stage for a packed agenda of EU research highlights and practical insights.
The session jumped straight into materials innovation, with Marta Hernaiz from TEKNIKER presenting the latest developments from the BEST-STORAGE project. She introduced advanced phase change materials (PCMs).
These are substances that store and release large amounts of energy when they change from a solid to a liquid and back, for example, paraffin waxes or salt hydrates. Hernaiz presented new cold storage solutions using phase change materials that outperform traditional water-based systems.
The aim? Smarter, more compact storage at lower temperatures, ideal for residential cooling and perfectly compatible with chillers and heat pumps. Two new prototypes are currently being piloted to store cooling energy in the 6–12°C range. These systems offer higher energy density and improved efficiency, potentially reducing operating costs while increasing chiller performance.
A case study from the Basque city of Bilbao followed, showing how thermal energy storagecan bring significant emissions reductions. In a city where the heat supply still relies on natural gas for up to 80% of demand, there’s huge potential for change.
Patxi Hernández and Arantza López from Tecnalia explored how combining heat pumps with innovative storage, like the ECHO-TES technology, can drastically cut operational emissions, especially as electricity grids shift further towards renewables.
Their life cycle assessment also highlighted the need to consider emissions from manufacturing and end-of-life, not just the operational phase: a reminder that full sustainability means looking at the whole picture.
However, challenges remain when it comes to scaling up.
Stefano Barberis from the University of Genova introduced the THUMBS-UP project, which aims to take thermal energy storage beyond individual homes.
The project is developing new technologies that promise high energy densities and flexible applications, from daily thermal management to using surplus renewable electricity. These systems are designed for seamless integration with heat pumps, offering real potential for grid balancing and energy optimisation.
Yet, high upfront costs and long payback periods are still barriers to wider adoption. This is where financial support mechanisms, such as Italy’s subsidy scheme for renewable energy communities, come into play, cutting payback times by more than 30% in some cases.
To wrap things up, Marco Rocchetti from R2M Solution zoomed out to the broader policy context. As part of the HYSTORE project, his presentation looked at the contribution of thermal energy storage to Europe’s circular economy.
With Europe still heavily reliant on imported raw materials for batteries and energy technologies, thermal energy storag eoffers a strategic opportunity. By designing systems for reuse and recycling, Europe can reduce dependence on global supply chains and increase its energy resilience, especially important in times of geopolitical instability.
The final word? Heat pumps and thermal energy storage aren’t just a technical match, they’re central to making Europe’s energy system cleaner, circular, more flexible, and more resilient.
Stay tuned for more updates from these exciting projects, and let’s keep pushing innovation forward, one step at a time!
