In this paper, a computational fluid dynamics (CFD) model is developed to simulate the methane (CH4) dispersion of exhaust gases from the Munich Oktoberfest, the world’s largest folk festival. Since we assume CH4 losses during the natural gas driven heating and cooking process, our aim is to provide a methodology for estimating these emissions. We developed a forward CFD dispersion model and combined it with on-the-site backpack measurements to quantify the emissions at the festival. The emission number is determined by scaling the simulated to the measured concentrations. Our sensitivity study reveals that the turbulent Schmidt number and the measured wind speed have high impacts on the emission results. Further, we investigated the effect of buoyancy, since there is a temperature gradient between the exhaust gases and the environment. Our results show that the buoyancy is an important factor for assessing hot emissions. Finally, we compared our findings to results determined by a Gaussian plume model and discussed advantages and disadvantages of each approach. Our findings show that CFD models can reproduce real dispersion processes in very complex environments with a high spatial resolution and are able to predict emissions. This study offers a completely new methodology to quantify local emissions on a real scale array and presents one of the first attempts to use CFD to study superimposed greenhouse gas sources.

Natural gas is considered a bridging technology in the energy transition because it produces fewer carbon emissions than coal, for example. However, when leaks exist, methane is released into the atmosphere, leading to a dramatic increase in the carbon footprint of natural gas, as methane is a much stronger greenhouse gas than carbon dioxide. Therefore, we conducted a detailed study of methane emissions from gas-powered end-use appliances and then compared their climate impacts with those of electricity-powered appliances. We used the Munich Oktoberfest as a case study and then extended the study to 25 major natural gas consuming countries. This showed that electricity has been the more climate-friendly energy source at Oktoberfest since 2005, due to the extensive use of renewable electricity at the festival and the presence of methane emissions, particularly caused by incomplete combustion of natural gas appliances. Further, our global study shows that using electric appliances for cooking and heating would be more climate-friendly not only at Oktoberfest but also in several countries around the world, depending on the energy mix used and the leakage rate of natural gas. With this study, we demonstrate one way in which countries with a high renewable share in power generation, in particular, can reduce a significant amount of carbon emissions in the future.