The state of the art in the evaluation of the ecological impact of various powertrain concepts is based on the evaluation of characteristics of existing vehicles on the market. However, these vehicles were developed with different objectives and are operated with various usage profiles. The potential of the powertrain concepts, if they were optimally designed for a given parameter set of a scenario to be investigated, remains unclear. But the knowledge of these optimal parametrizations of the powertrain concepts is necessary to enable an unbiased comparison of the technologies, especially if future scenarios are considered in which significant deviations from current parameter sets are possible. This work is based on results of the publicly funded FahrKLang project, in which an optimization framework for the comparative assessment of the "Real Ecological Impact" (REI) of various powertrain concepts has been developed. For each investigated scenario, optimal powertrain parametrizations of the various concepts to minimize the REI and a customized operational strategy are identified, thereby creating an equal evaluation basis. Representative driving cycles enable an efficient evaluation of the concepts based on real fleet driving data within the optimization environment.