Techno-economic optimization of pumped hydro storage plants integrated with floating photovoltaic

Pumped hydroelectric storage plants (PHS) with integrated floating photovoltaic power plants (FPV) represent a promising solution to the challenges of the energy transition. The combination of these two technologies offers a compelling synergy, with the potential to optimize the utilization of space, reduce water loss due to evaporation, and enhance the efficiency of PV modules through natural water cooling. This paper examines the potential for integrating FPV with existing PHS. The objective is to assess the possible techno-economic benefits of hybridization of the two systems with respect to standalone PHS. An optimization problem has been developed, formulated as a mixed-integer linear programming (MILP) model, in which the FPV panels are directly connected to both the electrical grid and the pumps, enabling either the sale of electricity or the powering of the pumps. The model highlights important relations between the two technologies, providing a specific correlation between water evaporation and variable purchase and selling electricity prices. The developed model has been applied to three existing PHS systems in Italy, which present different integrated potential parameters (IPP). This parameter, introduced in this work, is used to assess the potential of PHSFPV integration. For each plant four cases were considered for investigation, distinguished by different integration levels. Moreover, a sensitivity analysis is conducted to assess the impact of available surface area. The outcomes demonstrate that the integration of FPV in a PHS system enhances its economic and operational performance. The NPV of the three plants investigated exhibited an increase, with a maximum of a six-fold increase compared to the baseline PHS operation. The integration also results in an increase in the equivalent hours of PHS operation promoted by the variability in electricity prices and in a reduction of the water evaporation due to the presence of FPV panel while the available surface for installation emerges as the main limiting factor for the adoption of FPV technology.