Simulations of production systems is mainly a used to examine improvements or investments in a production system. Most often is this done using a static spreadsheet with process times and transportation times. For more sophisticated simulations Discrete Event Simulation (DES) is used with the advantages to simulate dynamics in the production system. A production system is very much dynamic depending on variations manufacturing processes, a assambly times, machine set-ups, breaks, breakdowns and small stoppages.^[48] There are lots of programs commersely used for discrete event simulation. They differ in usability and markets but do often share the same foundation. There is an academic project investigating the possibilities to use production simulation software for ecology labeling, named EcoProIT.