Molten Salt Storage 2

Challenge

The amount of renewable energy in the energy system will increase significantly in the coming years as part of the green transition. As the renewable energy from such sources as wind turbines is not constant, it must be stored, so that there is also energy available when the wind dies down — and preferably on a scale that can match the Danish, European, and (in the long run) global need for green energy. The main challenge of this project is to produce technical solutions for materials and concepts to withstand the very aggressive fluoride salts in the temperature range 600–880°C. At the same time, business cases must be developed based on the various solutions and at various sizes in order to identify the best combination of factors.

Solution idea

One method of energy storage with great potential is so-called “molten salt storage”, where green energy can be stored in salt systems.

In Energy Cluster Denmark’s Molten Salt Storage innovation project, a number of partners will be collaborating to validate a concept for an energy storage system based on molten fluoride salts in the temperature range 600–800°C.

The partners will collaborate to create a system design and qualify the business model for a plant that can store surplus power from such sources as wind turbines. When the need for energy arises — for example, in windless weather — the stored energy from the salt facility can be sent out into the energy or district heating network again via steam, driving a turbine for electricity and district heating production.

Project deliverables

Immediately following the project period, the partners expect that the plant will be demonstrated on a larger scale, and that the final design may become the first concept for widespread commercial use of molten fluoride salts for energy storage. The main deliverable will be the development of a complete “chemistry control” system design, ready for full-scale demonstration. Expected TRL level: 4. The most innovative work will be the development of Redox chemical control, combined with coated steel alloys to withstand high-temperature fluoride salts. The final design is expected to be the first concept for widespread commercial use of molten fluoride salts for energy storage systems.