The world’s first thermal storage facility based on molten hydroxide salts has been opened.

At the Esbjerg port in Denmark, the world’s first megawatt-scale energy storage system based on molten hydroxide salts has officially been launched. The MOSS (Molten Salt Storage) installation, developed by a consortium of industrial and scientific partners, is hosted at Semco Maritime and is designed to demonstrate that excess green energy can be efficiently stored as heat and later used to produce steam and heat for industrial processes and energy systems. The total project budget is DKK 24.7 million, with commercialization planned for 2026.

MOSS technology

At the heart of the new solution is a thermal storage unit using hydroxide salt heated to up to 700°C. Electricity from wind farms or photovoltaic installations is converted into heat and stored in a special molten salt tank. Thanks to the high heat capacity of the material, the energy can be retained for extended periods with minimal losses. When needed, the stored heat is converted into steam, which can drive turbines or be delivered directly to district heating systems and industrial processes.

The scalability of this technology is impressive. A tank 10 meters high and 20 meters in diameter can store 1 GWh of energy. Using it via a 100 MWt turbine could reduce CO₂ emissions by up to 110,000 tons per year, replacing fossil fuel-based energy sources.

Partnership and innovation

The MOSS project is the result of collaboration among a wide range of partners, including Hyme Energy, Din Forsyning, Alfa Laval Aalborg, Kirt x Thomsen, Sulzer, Seaborg, Aalborg University, and Energy Cluster Denmark. This combination of industrial experience, academic expertise, and energy-sector know-how forms the foundation for the project’s success.

Ask Emil Løvschall-Jensen, co-founder and director of Hyme Energy, emphasizes that the green transition is not an individual effort, but a shared mission. According to him, projects like MOSS demonstrate that bold innovations can change the world, with success depending both on technology and on users’ openness to new solutions.

Locally, the project is highly significant. The new storage system will act as a compact, flexible energy source, helping stabilize the power grid while enabling a gradual phase-out of fossil fuels in local heating. Din Forsyning views MOSS as a solution that can serve as peak and backup heat supply, supporting the goal of full decarbonization of deliveries by 2030.

Global perspectives

Energy storage is one of the key challenges for integrating renewable energy at large scale. MOSS offers advantages over many competing technologies: it is scalable to gigawatt-hour levels, uses cheap and widely available materials, and provides high durability with minimal losses. This opens the door not only to local applications in Denmark but also to commercial export of the technology to global markets.