Assessing the Role of Long-Term Electricity Storage in the Energy Transition

To achieve the objective of attaining a low-emission energy system, it is necessary to have precise energy planning to reduce the total cost of the energy transition. In the long run, energy models based on cost-optimal solutions heavily rely on the cost projections of various technologies. The purpose of this study is to determine a generic cost-optimal route for the decarbonization of an energy system. A linear programming model has been developed for this purpose, considering the synergies of the power sector with the heating, transportation, and hydrogen sectors. The results suggest that it is theoretically possible to have a system powered almost entirely by renewable energy, even with limited flexibility provided through interconnections. Power-to-X technologies are essential for balancing purposes because they enable a percentage of non-dispatchable production that approaches 90 %. In particular, the role of seasonal hydrogen storage is pivotal for accommodating significant penetration of variable renewable energy sources, which can also be combined with limited flexibility provision from other flexibility services suppliers. However, dispatchable and controllable resources such as biomass are of utmost importance for the system's well-functioning.