Modeling of power reserves and RES in optimization of Polish energy mix

Traditionally, energy mix was planned to provide electricity at the lowest cost, with respect to the power and energy balance, technical and environmental constraints and political decisions. However, the decision of the European Union to tighten climate policy has introduced new goals for the energy supply industry. In such reality, energy mix has to provide not only electricity at the lowest cost, but also to fulfill the international climate and political requirements. In light of the newest EU CO2 abatement targets and RES objectives, planning the energy mix has become much more complex. Volatile generation of RES increases the need for the fast reacting power system reserve. As a consequence, long term energy mix optimization, cannot rely on general requirement on the system reserve. It is necessary to consider particular category of reserve in the Generation Expansion Planning model: primary, secondary and tertiary. The paper focuses on linking energy mix optimization (long term planning) with the requirement of adequate power system flexibility (short term planning). The presented methodology for energy mix optimization, taking into account abovementioned issues, is illustrated by a case study for Poland.