As resources grow scarcer and mountains of construction waste pile up, Europe is rediscovering an old idea: the city itself can become a source of materials. And experts say this is no longer optional: “The cities we live in will have to become the biggest mines of the coming decades.”

As electric vehicles become "batteries on wheels", hotels and airports could be only the beginning. From balancing the grid to accelerating renewable energy integration, bidirectional charging could reshape the entire energy system — provided vehicles, chargers and the grid learn to speak the same language.