Project simulations are some of the advantages of using project simulations in SAP Project System. Project simulations are copies of projects that allow you to plan and simulate different scenarios without affecting operational projects. Project simulations can be created without using an operational project as a template, which means you can start from scratch or use a standard structure. Project simulations can be used to plan structures and costs, which means you can create and change WBS elements, networks, activities, and cost elements. Multiple project simulations can be used simultaneously, which means you can compare different alternatives and choose the best one. Reference: https://help.sap.com/doc/0f069b2e08b748f1b480d4c8b46c3c49/100/en-US/6a7a9f0a6e421014e10000000a174cb4.html