1. A system for handling a production disturbance/opportunity event in a production execution system, comprising: a network comprising a plurality of data processing units running a MES software for at least one of controlling and monitoring a production process operating a number of production components; a production modeler within the MES software enabled to define a plant model of the production process; a production scheduler within the MES software enabled to generate an executable production schedule for the execution of operating procedures for the production components related to the plant model of the production process; a production executor within the MES software enabled to execute the production process following the generated executable production schedule; and a production disturbance/opportunity event identifier within the MES software being enabled to detect a disturbance/opportunity event selected from the group consisting of a production disturbance event and a production opportunity event; wherein a single optimization engine simultaneously takes into account scheduling and execution decisions while recalculating a new production schedule and a new execution schedule based on the disturbance/opportunity event that has been detected.