Modeling the long-term development of electricity storage in the global energy system.

Summary The development of wind and solar renewable energies implies rethinking the long-term models of the energy system. Indeed, the short and long term impacts of wind and solar intermittent productions on the electrical system lead to a need for flexibility: highly reactive production plants, demand management, improvement of the electrical network or electricity storage. The first major contribution to the state of the art is the addition of electricity storage and the European electricity grid in the POLES (Prospective Outlook on Long-term Energy Systems) model. A new investment mechanism has been developed, better adapted to the challenges of renewables. It includes several economic values of storage. On the other hand, a new typology applicable to both energy forecasting models and detailed tools for the electricity sector has shown the interest of bringing together these two approaches. Thus, the second main contribution is the annual coupling of POLES to a power system operation model, EUCAD (European Unit Commitment And Dispatch), which optimizes the technical-economic allocation of European generation and storage plants. The bi-directional exchange of information allows us to benefit from both the long-term consistency of the POLES economic scenarios and the technical detail of EUCAD. A conservative scenario foresees a rapid development of the cheapest flexibility options: interconnections, hydro storage and demand side management - be it through load shedding or through the optimization of the charging and discharging of electric vehicle batteries. Stationary batteries, which are more expensive, are being developed in the second half of the century. Their development could be accelerated by a reduction of the fixed costs of storage, which is more effective than an improvement in efficiency. The explicit links between intermittent renewables and electricity storage are also apparent from the results.