Optimized operation of energy storages for primary control reserve

The electrical energy system is facing different changes especially with the focus on system planning and operation. Due to the change of the power supply with big conventional power plants to a system with more and more decentralized feed-in of regenerative volatile generation, it becomes complex to remain the system frequency stable. New technologies like energy storage systems (ESS) are needed to compensate these instable situations. Never the less the energy output of such system is limited by their energy capacity and makes the need of a state of charge management vital. In this contribution, a state of charge optimized operation model for ESS participating in the primary control reserve (PCR) market is set up. In addition to take part in PCR and meet prequalification requirements, special degrees of freedom for storages are taken into account to find the optimal ESS operation schedule. The model was tested with up-to-date annual frequency data from 2015 - 2017. Finally, the impact on technical operation as well as the possible speed-up in getting the return of invest was evaluated and valued.