Idle fee (parking fee)
The idle fee is an incentive to maximize accessibility to the charger since it prevents vehicles from blocking charging stations for extended periods, allowing other users to access the station.
As chargers are shared resources and not parking spots, Unplug When Ready to Go is one of the principles of EV charging etiquette. As soon as your vehicle is charged, unplug it to free up the charger for the next user.
The idle fee reduces the time that an EV occupies a charging station and increases the turnover of EVs at the station. Meaning that more EV drivers can access the charging infrastructure within a given time frame.