Most probably the untilization of storage technologies will increase significantly in future because energy suppliers are challenged to reinforce the application of renewable energy sources. As renewables are not available continously but fluctuate, it is essential to use storages for transforming the energy system with regard to sustainability. Another important fact is that heat has a share of about half of a country’s total energy consumption and is stored cheaper than electricity. In Austria 50% of the final energy consumption is heat.

Currently available storage technologies for heat and available implementing strategies for systems are not sufficient to reach the aim of 100% energy supply by the use of renewables. Therefore targeted research, development and demonstration of heat storage technologies is necessary. On the one hand compact thermal energy storages reaching higher energy density than water storages to apply with buildings, industry, mobility and relieving the grids, and on the other hand giga-scale water storages are in the centre of attention.

The current issue of „nachhaltige technologien“ shows the status quo with regard to national and international research dealing with various heat storage technologies and their applicability in different sectors.