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Flexible Resource Controller: A Price and Voltage-Responsive Device Controller for GridLAB-D Co-Simulations



David Holmberg, Thomas Roth


The Flexible Resource Controller (FRC) is a controller that manages heat pumps (HP), electric water heaters (HWH) and batteries with multiple objectives. The first objective is to manage energy use to save customer money—charging storage when electricity prices are low and avoiding energy use (or discharging battery) when prices are high, while maintaining comfort. A second objective is to implement reactive power control at the battery inverter based on local voltage levels (Volt-VAr) so as to minimize voltage excursions outside of acceptable limits. The FRC has been developed as a federate for transactive energy co-simulations to study the impact of price-responsive controls on voltage and other building and grid metrics. It takes as inputs the house thermal properties, weather and electricity price data and generates control variables (e.g., hot water temperature setpoint, battery real and reactive power settings) that are input to the GridLAB-D simulation engine on each time step. The FRC makes use of day-ahead hourly prices in addition to optional adjustment of control parameters in response to 5-min real-time prices. The FRC currently implements simple patterns that shift power usage based on prices. The FRC HP controller implements pre-cooling prior to the evening price peak and then a raised house setpoint temperature during the price peak. The HWH controller lowers tank setpoint in the afternoon. The battery is set to charge at night and discharge during the price peak. Battery inverter Volt-VAr voltage control is implemented independently of price response, operating at all hours of the day when activated.
Technical Note (NIST TN) - 2268
Report Number


Co-simulation, DER flexibility, device controller, dynamic price, GridLAB-D, price response, voltage control, Volt-VAr.


Holmberg, D. and Roth, T. (2023), Flexible Resource Controller: A Price and Voltage-Responsive Device Controller for GridLAB-D Co-Simulations, Technical Note (NIST TN), National Institute of Standards and Technology, Gaithersburg, MD, [online],, (Accessed May 30, 2024)


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Created September 25, 2023