What happens if PET is burned or used as a substitute fuel?

PET will burn like paper, wood, and coal.  Since it is very difficult to ignite and usually melts away from any flame sources, accidental ignition is unlikely.  In this respect, it is similar to most natural organic materials.  It has the same calorific value as soft coal (22-23 MJ/kg) and this energy can be very efficiently recovered in up-to-date 'Waste to Energy' power generation facilities.  Residues (ash) are measured in parts per million and can be disposed of with normal fuel ash.  The complete combustion gases are carbon dioxide and water, the respiration gases of plants and animals.  In controlled incineration, air emissions are contained below regulatory limits.