A follow-up study on the economic analysis of the
two energy storage technologies was performed in [20], showing
that the pumped storage has significantly lower life cycle cost
compared to battery storage, particularly when some variables
are controlled such as increased storage capacity and days of
autonomy, whereas this was just a case study and thus it might
not be the optimal system in terms of technical and economic performance.
Furthermore, the system modeling and techno-economic
optimization of the pumped storage based solar PV system
has been investigated in [21].