An electrical response system allows both traditional and renewable power generating system primary frequency response (PFR), fast frequency response (FFR) and inertial response systems to coordinate their response operations with an energy storage system and optimally pre-size the energy storage system and its charge. The response system allows the energy storage system to be optimally pre-sized by coordinating a power generating system to respond (a) during an over-frequency event by reducing active power output, and (b) during an under-frequency event by the storage discharging active power, thereby providing a coordinated response. Under-frequency events cause power generating systems to pre-curtail their active power output to meet grid requirements, thereby the system and method allows a power generating system to generate active power output at full nameplate capacity while simultaneously meeting electrical grid regulations and requirements.