This is a very attainable goal for a city like New York. I wonder what kind of an initial investment would be required to start such a system as well as the costs of maintenance and operation. I think this needs some more logistical research to determine whether or not it is cost effective in New York City. It may be more cost effective and environmentally friendly to simply use recyclable single use cups or even recyclable multi use cups made of perhaps aluminum or some similar material.
This seems like a good idea. It sounds like you want to start it in Germany which seems like it could work given the pre-existing infrastructure built for the plastic bottles. Do you have any ideas on how this would be expanded to other cities and countries. Additionally is this applicable to rural and suburban areas. I think this may be an idea limited to cities.