Detection and quantification of anthropogenic methane emissions in Germany using mobile measurements

The detection and quantification of anthropogenic CH₄ emissions is still a challenge due to the complex and heterogeneous distribution of the emitters and the large variability, e.g. leakages in the natural gas network, biogas plants, agriculture, waste and wastewater treatment.  Mobile measurements at street level, using cars or bicycles, are a good way to detect methane emission sources. The measured CH₄ peaks can be converted to emission rates using a Gaussian plume model.

The emission factors for the waste and wastewater sector as well as for biogas plants are still subject to large uncertainties. In this study, mobile measurements for several CH₄ source categories in Germany are presented. The main focus is on CH₄ emission rates from the waste and wastewater sector and from biogas plants. We performed mobile methane measurements to detect emission plumes from more than 30 different biogas plants in Germany, focusing on one biogas plant for long-term monitoring since 2016.  Methane emission rates ranged from 0.1 to 46 kgCH₄/h. This corresponds to a loss relative to the biogas production rates of 2 to 13 % l. Measurements at several wastewater treatment plants show CH4 emission factors between 0.04 and 1.9 kg CH₄/a per capita.

The determined emission rates are statistically analysed and compared with the emission factor used in regional and national inventories.