Friend and co-author JH sent me this link a few months ago, describing how some laboratory scientists have been able to convert used Tim Horton cups into an ethanol fuel.
Sparling and Levin collect the raw materials for their research by setting up bins outside campus Tim Hortons outlets. The cups are brought back to the lab, where they are put through a paper shredder and eventually converted into a mulch resembling pink cotton candy. That increases the surface area that the bacteria can latch onto in order to start munching, speeding up the process.
The mulch is loaded into a bioreactor, where the environment, including the temperature and pH, is controlled to make the bacteria comfortable and help them process the mulch efficiently. Then the bacteria are added, and they go to work.I wonder how much traditional energy must be used to produce ethanol this way. I'd guess it would be lots.
As JH implied when he sent me the link, there is probably a much more interesting use for used Tim Horton cups. See this.