Assessment of the Effectiveness of Energy Storage Resources in the Frequency Regulation of a Single-Area Power System

An energy storage resource (ESR) has outstanding ramping capability, but its limited energy disables the provision of regulation service around the clock. As a comparison, a conventional generator (CG) is not restricted by the released energy, but the ramp rate is limited. In this paper, a method is proposed to evaluate the effectiveness of ESRs providing frequency regulation service in a single-area system. We measure the performance of frequency regulation by the standard deviation of system frequency excursions, and define the regulation requirement of an isolated power system as the minimum regulation capacity which satisfies the desired regulation performance. By analyzing the regulation requirements under different combinations of regulation resources, we can quantitatively compare the effectiveness of CGs and ESRs. Case studies show that ESRs can reduce regulation requirements, indicating that they are more effective than CGs in frequency regulation. However, they become less effective and even outperformed by CGs when they constitute a larger portion of the system regulation capacity.