In Vojens, Denmark, known for its less sunny climate, the world’s largest seasonal solar heat storage project has been operational since 2016. This extensive storage functions as a seasonal heat storage, enabling the solar heating plant, which is the third largest in the world, to contribute over 50% of the annual heat production to the network.

The remaining heat is generated by three gas engines, a 10 MW electric boiler, an absorption heat pump, and gas boilers.