Energy storage for use in load frequency control

Certain energy storage technologies are well-suited to the high-frequency, high-cycling operation which is required in provision of load frequency control (LFC). To limit the total stored energy capacity required while reducing the cycling burden on traditional thermal generators, the LFC signal may be split between thermal generators and energy storage units. To evaluate the dispatch of energy storage units in concert with thermal generators, this paper presents energy-duration curves and ramp-rate-duration curves as graphical tools. The energy storage requirement and thermal ramping requirement may also be graphically compared to provide insight for cost evaluations.