This RP focuses on recommendations for three main aspects of grid-connected energy storage: safety, operation and performance. These aspects will be assessed for electricity storage systems in general, but also with emphasis on certain battery technologies (lead-acid, Li-ion and redox flow) and Li-ion capacitors. Other storage technologies, like flywheels, pumped hydro storage, compressed air and supercapacitors, are included in more general terms. Future updates of this RP are likely to expand the range of storage technologies covered.

Explicitly out of scope is chemical and thermal energy storage, such as hydrogen storage or heat storage. Electric vehicles are not currently considered to be grid-connected storage and are not considered within scope. No restrictions are foreseen with respect to the application types of energy storage systems; any electricity storage applications at the high, medium and low voltage grid level as well as home energy storage are considered within scope.

The proposed guidelines are limited to common requirements, based on worldwide accepted regulation and best practices like IEC, ISO and IEEE standards. This RP cannot guarantee a fully secure storage system: new technology will always invalidate previous designs and safe components will not automatically result in a safe system.