The realization of a carbon-neutral society requires a new energy system, and Green Transformation (GX) technology is necessary to achieve this. As renewable energy is becoming the main power source, one important issue is the stable utilization of the unsteady output of renewable energy, which fluctuates on the order of GW. Energy storage technologies will be needed to meet this challenge. Optimization and advancement of Energy Storage Mix (EMS) utilizing various energy storage technologies is an important GX technology. This paper will provide an overview of the necessity of EMS and show the potential of thermal energy storage technology and carbon recycling technology, which are expected to progress as energy storage technologies.