New findings from the European SALTOpower project highlight molten salt batteries as a scalable solution to strengthen energy storage, support renewables, and enhance Europe’s industrial autonomy
Molten salt batteries for energy storage and SALTOpower insights
ENEA has released the results of the European research project SALTOpower, focusing on the use of molten salts for battery technologies and energy management.
According to ENEA, molten salt batteries represent a strategic alternative for energy storage in Europe, offering a pathway to integrate renewable energy while reducing reliance on critical raw materials.
The findings show that thermal energy storage systems can deliver grid flexibility, stability, and industrial autonomy. The research emphasizes the integration of molten salt systems into multifunctional energy hubs capable of combining electrical, thermal, and chemical energy.
With roughly 77 GWh currently installed, Europe still covers only a limited share of future storage demand. In this context, molten salt storage emerges as a scalable and modular solution, suitable even for isolated or remote areas.
Physical properties and industrial advantages of molten salt batteries
Molten salt storage relies on materials such as nitrate salt mixtures, already widely used as fertilizers, which offer favorable technical characteristics for energy applications. These materials ensure high thermal stability, strong heat storage capacity, low vapor pressure, and wide operating ranges, making them suitable for high-temperature processes.
These properties explain why molten salts are already a standard in concentrated solar power plants. They allow energy to be stored during periods of excess production and released when demand rises or generation drops, enabling dispatchable and programmable supply.
Another strategic advantage lies in raw material availability. Unlike lithium-ion batteries, whose supply chains are heavily concentrated in China, molten salt technologies rely on abundant or easily sourced materials in Europe, strengthening the continent’s industrial independence.
Integration into energy systems
Integrating molten salt batteries into energy systems is a core focus of SALTOpower. The research explores the development of multifunctional energy hubs where electrical, thermal, and chemical energy flows are managed in a coordinated way.
These systems connect different energy networks and enable conversion across multiple vectors. Power-to-heat and heat-to-power technologies convert electricity into heat and back, while heat-to-gas and gas-to-heat processes further expand integration capabilities.
Thermal storage becomes a key enabler for increasing the share of non-dispatchable renewables such as wind and solar, while mitigating grid stability challenges.
Carnot batteries and thermal storage applications
One of the most promising applications studied in SALTOpower involves so-called Carnot batteries. These systems use thermodynamic cycles to convert electricity into heat and then back into electricity, enabling high-capacity and flexible storage.
The research evaluates different technological solutions, including resistive heating and high-temperature heat pumps, alongside thermal conversion cycles. The goal is to assess both technical and economic performance, with a strong focus on grid integration.
At the same time, the project investigates the production of renewable gases through thermo- and electrochemical processes, including high-temperature electrolysis and biomass pyrolysis. These technologies enable the production of hydrogen and syngas, expanding the role of molten salt storage into the renewable fuels sector.
A European hub for storage research
One of the key strengths of molten salt storage technologies is scalability. Stored energy capacity can be increased simply by expanding tank volume, without changing the working fluid or underlying technology.
Over the past decade, European research has advanced significantly in this field, supported by dedicated infrastructure in Germany, Italy, and Portugal. In particular, the development of a pilot plant in Évora has strengthened testing and innovation capabilities.
SALTOpower aims to establish a European reference framework for research in this area, enhancing scientific, technical, and administrative expertise while fostering collaboration between institutions and industry.
A strategic lever for Europe’s energy security
Molten salt storage could play a central role in ensuring energy security and system resilience. The use of locally available materials reduces dependence on external supply chains and reinforces Europe’s industrial competitiveness.
At the same time, the modular nature of these systems allows deployment in remote or off-grid areas, helping address energy access challenges. This is particularly relevant for expanding renewable energy in regions with limited infrastructure.
