Iron silicate with a grain size of 1.8 - 2.4 mm was tested as a new storage medium in our TESS 3A test storage facility. The first measurement results show very successful tests with an approx. 15 - 20 % higher energy density compared to silica sand.

This higher energy density enables a significantly smaller design of the HTTES, which means that the specific investment costs per kWh can be significantly reduced.