A predefined reserve capacity for operating and standing reserves has always to be maintained. Furthermore, the possible contribution of every single power plant to the operating and standing reserves is described by further technical restrictions in the model. The energy loss during the charging and discharging process is combined to a cycle efficiency of the storage which is considered during the charging process. For each planning period covering the horizon of one short-term forecast, one optimisation problem is defined. Yet, the consideration of one single short-term forecast is not sufficient for a comprehensive analysis of the annual unit commitment and dispatch of an electricity system. The determination of the optimal unit commitment and dispatch for a longer and continuous period is required.