Determination of biogas process efficiency - a practice-oriented alternative to the biomethane potential test

The energy efficiency of biogas plants is fundamentally based on the biochemical degradation of input materials. This paper introduces a novel method of efficiency determination based on the gross calorific value (GCV), a very common method in conventional power generation. GCV investigation of five commercial biogas plants in northern Schleswig Holstein were conducted by a one-year time series analysis with weekly sample taking. Although initially a simple model was used to estimate the lignin content, the plausible results indicate the suitability of the proposed method. For comparison, methods like the FoDM and the classical biomethane potential test are highlighted to point out their traditional usage and their adaption for the biogas sector. Also the laboratory efforts they cause is taken into account.