Methane emissions along the natural gas supply chain are critical for the climate benefit achievable by fuel switching from coal to natural gas in the electric power sector. For Germany, one of the world’s largest primary energy consumers, we conducted fleet-conversion modelling taking domestic and export country specific emissions in the natural gas and coal chains into account. Methane leakage rates below 4.9 % (GWP20; immediate 4.1 %) in the natural gas supply chain lead to overall reduction of greenhouse gas emissions by fuel shifting from lignite and hard coal to natural gas. Reported supply chain methane emissions for Germany’s natural gas mix are with < < 1 % leakage rates well below this Germany-specific break-even leakage rate. Even a potential supply by U.S.-American liquefied natural gas to Germany would not exceed this critical rate. Supply chain emission scenarios demonstrate that a complete shift to natural gas would emit 30–55 % less greenhouse gases than from the coal mix. However, further abating supply chain methane emissions in the oil and gas sector should remain a prime effort, when considering natural gas as bridge fuel on the path to achieve the Paris climate goals.