Assessment of Energy Storage Potential for Primary Frequency Response Adequacy in Future Grids

Abstract

Variable demand pattern with large integration of Renewable Energy Source (RES) would challenge utilities, to ensure inertia and primary frequency response (PFR) adequacy. Displacement of synchronous generators, further results in reduction of system’s inherent inertia and PFR capability. This would pose system security and reliability concerns, particularly at the time of contingency like largest generation outage or loss of large chunk of load. These megawatt (MW) imbalances requires an additional response, to make system frequency stable. In view of these issue, this paper assesses potential of energy storage for PFR adequacy in day- ahead generator scheduling problem by simultaneous consideration of operation cost minimization, netload variation and largest generator outage. Simulations are performed on IEEE-118 bus test system with step wise increment in PV and Wind penetration. System inertia quantum, rate of change of frequency (ROCOF) and frequency deviation at nadir is considered as frequency security parameters for the assessment of PFR adequacy. Obtained results presents systematic analysis of energy storage contribution to mitigate PFR requirement at different RES penetration and improvement in frequency nadir. Further, operation cost analysis is presented with variation in RES penetration. This analysis would help system operator to pragmatically handle inevitable system contingencies. This framework could be potentially enhanced to incorporate technologies like, demand response & electric vehicles in future low carbon power system.