Economic evaluation of energy storage systems for grid-scale applications. Part 2: analysis and results

In this Part 2 we perform an economic evaluation of the candidate energy-storage systems (ESSs) selected in the previous Part 1 for two different applications in medium-voltage (MV) distribution systems: power quality (PQ) improvement, and full local exploitation of the photovoltaic (PV) generation. The first application is power intensive, the second energy intensive. Accordingly, the ESS power/energy specifications are different. Starting from the two sets of candidate technologies and their specifications, and using the methodology outlined in Part 1, in this Part 2 we calculate, for each case and each candidate technology, the annual benefits and two economic indices: the pay-back time (PBT) and the net present value (NPV). The results, compared and commented, provide information on the current sustainability of different storage technologies in the frame of different grid-scale applications – either power or energy intensive – in MV distribution systems.