This paper focuses on increasing power plants' flexibility of fast ramp-up ability. At first

combining with the experimental results

the actual AGC response ability of the current thermal power units are analyzed

it finds out that there is still a certain gap between the existing thermal power units and the expected targets. On the basis of discussing the coordinated optimal control technology

the load regulation technology based on the unit's self energy storage ability

and the load regulation technology based on energy storage

a united energy storage system is proposed to enhance the AGC response ability of the units. Moreover

the running property

thermal characteristics and project investment are analyzed in detail. The results show that the united energy storage system can realize the regulation quality close to the pure battery energy storage scheme

and has the characteristics of lower investment and higher safety

so it has a strong promotion significance.