Investigation of energy storage and open cycle gas turbine for load frequency regulation

In power systems, load is continuously fluctuating and is difficult for slow generating units, such as coal-fired, nuclear and hydro power plants, to follow. Therefore, fast but expensive generation units like open cycle gas turbine (OCGT) are widely used to provide frequency regulation, maintaining system frequency within its specified limit. Owing to energy storage system (ESS)´s zero-net energy and fast response nature, one of the applications of ESS in power system is to provide frequency regulation. This paper proposes a method of sizing OCGTs and advanced lead-acid batteries to provide frequency regulation under different types of load following patterns. The rain-flow counting algorithm is used for battery lifetime modelling. The cost and savings from displacing OCGTs with ESS are calculated and discussed. It was concluded that the system load following ability is the key factor when considering whether ESS is cost effective when providing frequency regulation in a control area. The method of battery and OCGT rating presented in this paper is applicable to the situation when regulation load requirement is known or can be estimated.