Analysis of Battery Energy Storage for Frequency Response Services

As the use of renewable energy sources (RESs) increases worldwide, there is a rising interest in their impacts on power system operation and control. These resources are considered variable, independent, and intermittent by nature and can contribute to power quality, stability, and reliability issues. To overcome such problems, in Great Britain (GB), the National Grid Electricity System Operator (NGESO) – the primary electricity system network operator – has introduced various frequency response services to provide a real-time response to deviations in the grid frequency. Battery Energy Storage Systems (BESS) are considered a good solution to deliver such services to the grid. In this thesis, the control algorithm for a generic BESS has been implemented in Matlab Simulink to deliver frequency response services according to National Grid (NG) specifications. Moreover, this thesis presents a sensitivity analysis of the power-to-energy ratio for Energy Storage Systems (ESS) providing frequency services with respect to availability, compliance against service terms and conditions, and lifetime. It shows that there is a significant difference between the frequency of services and demonstrates that the newer dynamic containment service can be effectively delivered by a higher power-to-energy ratio ESS, offering opportunities for other technologies such as supercapacitors and flywheels. Control methodologies are investigated that exploit the delivery envelopes to manage the state of charge and improve the availability of a battery energy storage
system, potentially resulting in higher revenues, an increase in cycle life, and decreased penalty payments. To investigate life-time, different methods to analyse battery operation to provide degradation estimates are presented which are then informed through experimental work. Finally, in this thesis, the financial costs of using GB’s electricity system have been investigated and simulated to provide a comparison between delivering different frequency services.