An example of how frequency is closely monitored before energy demand surge in Britain due to Tea Time:
https://www.youtube.com/watch?v=slDAvewWfrA https://www.geek.com/geek-cetera/tea-time-in-britain-causes-...
https://www.youtube.com/watch?v=slDAvewWfrA https://www.geek.com/geek-cetera/tea-time-in-britain-causes-...
> TV pickups [...] are a surge in demand caused by the flushing of toilets (leading to a surge at the pumping stations) and the opening of fridge doors by millions of people. There is a common misconception that the number one driver of TV pickup is the boiling of kettles. In fact, this only creates a pull on the local network for a short period of time until the water has boiled, and can therefore be managed relatively easily, whereas flushing the toilet causes a longer surge at the water and sewerage pumping stations, and opening the refrigerator lets the chilled air escape, causing the compressor to run.