Energy storage affirms itself in transition: The energy system will not be able to do without storage; PepsS: the relevancy of storage solutions is assessed; Giga-factories settle in Hauts-de-France; Diving in the heart of the biggest storage plant in Europe; Batteries to smooth hydro-kinetic production; Some storage in Mayotte for more renewables; To improve batteries thanks to optic fibre; A new life for batteries of electric vehicles

A set of articles addresses various aspects of energy storage to illustrate its role in energy transition. Articles outline that energy storage is the answer to the necessity of decarbonization of the electric power system and to change energy consumption modes, comment results of a study (PepsS) which assessed the relevancy of different energy storage systems, briefly comment the application of the concept of giga-factory to battery factories in France, briefly present and describe the Belgium Lessines energy storage plant (the biggest in Europe which keeps the half of Belgium's primary reserve), and evoke the French Corsica Sole plant. They also outline the use of batteries to smooth hydro-kinetic electric power production (installation located offshore the Ouessant island, project in the North of Scotland), propose a brief overview of energy storage plants (realised and projected) in Mayotte which will allow more renewable energies to be integrated while the island is still extremely dependent on fossil energies. An article evokes works performed by different French research teams in the development of a method based on optic fibre to directly monitor the chemistry within batteries all along their lifetime. The use of batteries of electric vehicles after their loss of autonomy for stationary storage is addressed (use by manufacturers, search for optimisation). Brief presentations of realisations are proposed (French research programme on batteries, a 40 MW storage system by Neoen in Sweden, a 100 MW storage site in New-Zealand)