With the continuously rising share of renewable energies in the energy supply system, energy storage systems for electrical and thermal energy are becoming increasingly important. If electricity is converted before it is stored, for example into hydrogen or other chemical energy sources, this energy can not only be later re-electrified but also used in other energy industry-related sectors and thus for the much-needed coupling of the various sectors.
Heat storage systems can be used for integrating renewable energies, especially in combination with solar thermal heat for space and domestic hot water heating in buildings as well as for industrial processes. Renewable electricity from photovoltaics and wind energy can also be stored by converting the electricity into heat (power-to-heat). Thermal energy storage systems can therefore be used to shift the demand for heating and cooling energy. They can also increase the overall efficiency when generating electrical energy, for example by storing the waste heat from CHP plants.