[ZeroGravitas]

The big point is demand response in smart heaters allowing time shifting.

He also, confusingly, makes a second point about how efficiency can to avoid building powerplants/storage.

Replacing old inefficient heaters with new smart and efficient heaters is a double win.

If you power them from renewables it's a triple win.

Also night time energy is often low carbon because of nuclear and wind combined with low demand, but modern smart heaters can respond at a much smaller scale to use "excess" energy.