Cooperative control of energy storage systems and biogas generator for multiple renewable energy power plants

The Ministry of the Environment of Japan is promoting a demonstration project named "wide-area operation systems for multiple renewable energy (RE) power plants" in which the authors have been devoted. In this project, the generation outputs from five RE power plants are monitored online and the fluctuation in total output is absorbed by a combination of three different energy storage systems (ESSs) and a biogas engine generator (BG). In this paper, a cooperative control of three ESSs and BG is developed considering the difference of characteristics such as the ratio of energy capacity [kWh] to power capacity [kW] (energy/power ratio) and the dynamic response. The purposes of this system are 30-minute balancing between the actual and scheduled output and absorption of the short-term (less than 30 minutes) output fluctuation. Additionally, this paper also describes capacity and control parameters design procedure based on the cross entropy method, which is one of the optimization techniques. Simulation results show that the wide-area operation system can effectively reduce the required ESSs capacity to stabilize RE output.