This work performs a preliminary comparative economic analysis of various energy-storage systems (ESSs) for MW-scale applications in medium-voltage (MV) distribution systems. Two specific applications are analyzed, depending on the amount of the total local photovoltaic (PV) generation. In case of a low PV generation, the ESS is used to improve the power quality (PQ). In case of a high PV generation, the ESS is used to allow a full local consumption of the PV generation as well as to improve the PQ. The two cases imply different power/energy specifications for the ESS and, thus, different candidate storage technologies. In this Part 1 we: 1) illustrate the methodology used; 2) select the ESS power/energy specifications in both cases and 3) define, for each case, a set of candidate storage technologies. For each of these candidate solutions, detailed calculations and results are reported in the following Part 2, where the current ESSs sustainability for MW-scale power and energy applications is finally discussed.
