This thesis addresses the future need for more decentralized energy management as the existing concepts of our energy systems are challenged by the inevitable increase in renewable and clean resources. This energy transition is underway and new solutions for load steering in energy grids will make it possible to integrate end users who have been passive in the traditional energy system. For this purpose, these local actors must be shown what added value their participation in future energy systems can have for them. The focus of this thesis is on the economic added value through cooperative collaboration between participants by optimizing their operational planning processes. Therefore, a modular mathematical model is  presented that aims to maximise the participants' savings through direct energy exchange between the participants and also the alternative use of local flexibility options. The modules presented are also examined in a detailed impact analysis. The operational optimisation additionally provides a quantitative basis for subsequent strategic and tactical decision support for such cooperation. However, for such strategic planning to be sustainable, a cooperation must remain consistent. This thesis therefore concludes with an initial game-theoretical analysis of this particular form of cooperation, in which both suppliers and customers work together.