Hybrid Energy Storage Technologies provide the opportunity to combine complementary characteristics and to overcome barriers and drawbacks of single technologies alone. The European targets to increase the renewable energy penetration in the energy system (e.g. Fit for 55 and REpower EU) implies a key role for energy storage enabling a range of services providing performance and sustainability at the same time. Rather a combination of various energy storage technologies (electrochemical, chemical, thermal, mechanical and electrical storage) is needed in order to provide the expected performance regarding energy system capacity and duration offering the desired flexibility. Moreover, the more renewables will penetrate the market, the greater the need of flexibility in energy storage applications in face of changing market conditions.

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Combining a high-energy storage technology with high-power technology is one of the common approaches as, for example, the combination of Superconducting Magnetic Energy Storage (SMES) or supercapacitors with batteries would offer, or electricity storage with conversion in chemicals (P2X) for long-term, large scale energy storage. Such combinations shall also ensure an optimal use of materials for storage technologies thus contributing to increase the sustainability of the energy system as a whole.