The aim is the development of innovative materials and technologies for rock heat storage, and the  operation design of an energy storage facility. Energy storage is crucial for the energy sector transformation, aligning electricity production from RES in summer with winter heat demand. With positive results, application in the medium term is anticipated. The goal is to experimentally demonstrate selected approaches. Success could aid the heating sector's transformation to low-emission operation under specific conditions (e.g., mining sites near agglomerations using CHP systems). If summer's surplus electricity from PV (excess EE, low prices) is utilized in winter, these solutions may advance the objectives of the Czech Republic's National Energy and Climate Plan. 