Optimizing integration of the new RES generation and electrical energy storage in a power system: Case study of Croatia

In the context of sustainable development and aspirations for the low carbon future, renewable energy sources are imposed as the foundation of the power systems of the future. Due to the unpredictable nature of these sources the adaptation of traditional power system to new conditions is necessary. This change is particularly needed in the form of generation which is able to balance supply and demand in realtime due to renewable energy sources intrinsic variability and in the form of a new systems for energy storage. This paper, through scenario analysis and optimization, considers future prospects of a new renewable energy sourced generation in the Croatian power system. It analyses the significance of the energy storage systems and the flexible power plants. Paper has analysed several scenarios of high level RES penetration into the Croatian power system. Analysis was performed in conservative manner, assuming there is no external market available. It has been shown that the capabilities of the current state power system are such that it is able to sustain RES penetration levels from 2000 MW to 3000 MW without large curtailment (less than 5%) of available RES energy, depending on the structure and mix of RES, primarily wind and PV energy. The result of the research is: the analysis on the maximum amount of renewable energy that can be integrated in the Croatian power system while accounting for different availability of imports of electricity from EU electricity markets; the analysis on the necessary conditions for significant penetration of renewable energy sources in the Croatian power system and limiting factors that affect this. Analysis shows importance of heat storage systems with electrical heaters which can significantly contribute to decrease of curtailed RES energy, since they are capable to directly transfer excess electricity to district heating systems. It is therefore important to direct future researches into coupled modelling of power and heat systems in order to better comprehend benefits of such simultaneous optimizations regarding future RES integration.