I'm not exactly sure of the context of the question.
Electricity plants use the excess heat for district heating. It isn't just wasted.
If we could suddenly stop using coal or other combustibles for electricity production, we'd still need to produce energy for heating.
Transport is different though. Gasoline engines are highly inefficient and produces a lot of excess heat that isn't used even when the heater is on full blast.
It's not much in comparison to power production though, so while it will be more efficient to drive and heat a car by electricity, excess heat from cars isn't really an issue in itself. It's the pollution that is the main issue.