Abstract: Typical energy storage resources（ESRs）,like battery storage systems,can change their power outputs with very high speeds,which provides automatic generation control（AGC） with a new measure.The paper works on the capacity requirement and the control strategy of ESRs participating in AGC.Based on the analyses of power system frequency regulation requirement,a method is proposed to quantify the low and the high frequency component of regulation requirement using discrete Fourier transform.Then two control strategies are presented for ESRs participating in AGC according to their fast response merits.The first strategy flexibly allocates the regulation capacity to ESRs according to the zone of the area regulation requirement（ARR）,while the second strategy assigns the high frequency component of the ARR to ESRs.Using the historical data of a real system,simulations are carried out to compare and analyze the effectiveness of different AGC strategies for ESRs.The proposed methods and simulation results are important for practical implementations.