Geographic information system and EnergyPLAN-based assessment of pumped hydro storage potential for renewable integration in the power grid

Pumped hydro storage is a long-established method of electricity storage, but its reliance on geographical factors limits its large-scale deployment due to various barriers. In this study, a geographical information system-based approach is proposed, which utilizes multifunctional small- and medium-sized dams to expand pumped storage capacity. The potential for pumped storage system installation in Japan is evaluated. The large-scale integration of stochastic and uncertain variable renewable energy, primarily comprising photovoltaic and wind power, into power grids poses significant challenges to optimal dispatch operations in energy systems. Pumped hydro storage exhibits the capability to mitigate these challenges through its peak-shaving and valley-filling attributes, effectively flattening load curves by compensating for variable renewable energy intermittency and reducing dispatch complexities for conventional power generation units. Additionally, actual operational data from Japanese thermal power plants is incorporated into the analysis to optimize the configuration of the energy supply system and evaluate its impact on grid performance and the ability to absorb variable renewable energy. Kyushu and Hokkaido—regions with distinct power supply structures, load profiles, and pumped hydro storage system development potential are used as case studies. EnergyPLAN software models hourly outputs for various power generation units under different scenarios. The study evaluates renewable energy penetration, thermal power generation compression, and reductions in unit power generation costs across these scenarios. The results indicate significant potential for pumped hydro storage system development in Kyushu and Hokkaido, with projected capacities increasing by 7.6 and 25 times their current levels, respectively. The operational strategy for pumped hydro storage system varies according to the power generation mix, with thermal power and nuclear power influencing the outcomes. When photovoltaic penetration remains below 65 % in Kyushu and 55 % in Hokkaido, the cost of integrating energy storage exceeds system savings. However, beyond these thresholds, energy storage reduces total system costs by 2 yen/kWh.