The main goal of this work is to study the role of energy storage in the context of the Portuguese power system by year 2030. Portugal is one of the countries in the world with more installed energy storage capacity, namely Pumped Hydro Storage (PHS). The simulations are performed with EnergyPLAN tool and allow to predict the energy mix in Portugal by year 2030; to forecast the utilisation of the storage capacity, namely projections for the energy produced by PHS; to estimate CO2 emissions and percentage of Renewable Energy Sources (RES) utilisation; to assess the necessary storage capacity to avoid renewable curtailment; to evaluate the future needs of installing further storage capacity, either with more PHS capacity or with the introduction of batteries. PHS revealed important to avoid the curtailment of renewable energy, especially in a scenario of higher RES shares. It is shown that the increase in RES contribution would decrease the overall costs of the system, leading to thinking that further efforts should be made in increasing RES installed capacity, and go beyond the official RES predictions for 2030. It is also concluded that the predicted storage capacity for 2030 can accommodate the expected increase in variable renewable generation with no need for further investments in PHS or battery solutions.