Overview of medium scale energy storage systems

In this paper, an overview of energy storage systems alternatives to use in medium energy scale applications is done. The considered technologies are compressed air, pumped hydro, superconductors, flywheels and supercapacitors. The last four are suitable for the medium scale applications (as 100 kW photovoltaic generation plants) which this paper is focused on. The supercapacitor alternative is studied in more detail, presenting these device structures, how they can be modeled and their principal applications. The overview is carried out after a detailed reference selection.