This is a smaller use case—folks living in apartments without direct electricity connection. While the case exists and can be improved separately it shouldn't dictate requirements/costs to the rest of us.

Think I'd try to solve that by having the customer register the car/payment once at the kiosk and then handle plug-and-charge-and-bill though your service. Then you don't need to wait for an external solution and can advertise convenience as your added value in the meantime.