Germany appears set to miss its CO2 reduction target in 2020. As a result, ideas for additional political measures have been put forward. One such idea involves an early phase-out of coal-fired power plants. However, the possible impacts of such a phase-out on the energy system have not yet been fully analyzed. We therefore apply a German energy system model to analyze these impacts. To do so, we calculate three different scenarios. The first represents a business-as-usual scenario, while the second takes a coal phase-out into account. The third scenario has to achieve the same CO2 reduction as the second without being forced to implement a coal phase-out. Our three scenarios show that a definitive coal phase-out by 2040 would result in only a relatively small amount of additional CO2. However, an equal CO2 reduction can be obtained using a different strategy and slightly lower costs. In the latter scenario, the additional costs are also distributed more evenly across the sectors. The sensitivities analyzed show the robustness of the conclusions drawn. In summary, this analysis outlines what consequences could arise by excluding several options in parallel from a technology portfolio. (C) 2017 Elsevier Ltd. All rights reserved.