In the project HyStEPs – Hybrid storage for efficient processes an innovative hybrid storage concept will be developed to increase the storage capacity of existing steam storage units by up to 40% while reducing the investment costs of existing steam storage units. The project team is developing an innovative hybrid storage concept and testing it experimentally to increase the storage capacity of operating Ruths steam storage units in the medium term. The following questions have to be answered: the thermal connection of the latent heat storage elements to the steam storage, the increase of the thermal conductivity of the phase change material through heat conducting structures, corrosion behaviour of the material combinations but also strength calculations.