How would a dynamic demand controller actually work?
To paritipate in second-to-second balancing of the grid, the device must be able to measure accurately the power system’s AC frequency (nominally 50Hz in the UK) which is a good indicator of the instantaneous balance between supply and demand. Grid frequency is kept within strict bounds by the grid operators to ensure that the system remains balanced. See the UK frequency limits here. See the current system frequency here.
