Dynamic Building-to-Grid Integration through Combined Building System Resources for Frequency Regulation Service
Frequency regulation (FR) is the electric grid service responsible for maintaining the system frequency at its nominal value of 60 Hz in the United States--an indicator of energy balance on the grid. In cases of mismatch between power supply and demand, frequency regulation resources either on the generation or the demand side, responding rapidly to restore system frequency to its nominal value. Due to the limited responsiveness of electric generators, fast and accurate demand side resources (DSR) have recently been encouraged to participate in frequency regulation. The tested DSR's include flywheels and battery banks. However, high initial equipment investment is typically required for these projects. Large commercial buildings dominating many urban cores have been shown to provide effective load shaping with little or no impact on occupants' comfort. This allows FR participation by manipulating the operation of heating, ventilating and air-conditioning (HVAC) systems. Commercial buildings are characterized by numerous interdependent HVAC subsystems and their controls. Therefore, a high-level supervisory control strategy is developed to take advantage of interactions between HVAC subsystems for FR with buildings' available capacity. This dynamically integrates building operations into grid operations (i.e., the ancillary services market) so that both parties know each other's capacities and constraints ahead of time. Unlike traditional demand response (DR) programs that engage only sporadically during times of grid stress, dynamic building-to-grid integration automatically and continuously provides solutions from the demand side maintaining energy balance on the gird. The benefit is expected to go beyond any current demand response programs.