The Danish energy company, Andel (former SEAS-NVE) has developed a high-temperature thermal storage solution in collaboration with the Technical University of Denmark, Aarhus University Geoscience, the Danish Energy Association, Energinet and Rockwool. In this, the energy is stored in rocks heated up to 600 degrees with air from an electric fan heater. The heat will later be extracted to drive a conventional electric turbine. The ambition is to implement the solution on a large scale throughout Denmark at competitive prices, while addressing the challenge of storing large amounts of energy in a cheap, environmentally friendly manner.