The cost-effectiveness of biogas plants is largely determined by the substrate costs, which constitute 40 to60% of the annual operating costs.in Germany, where energy crops are widely used in anaerobic digesters. When planning and operating digesters, understanding the relationship between the methane yield of different substrates in the lab compared to full-scale operating biogas plants is very important. The determination of the methane yield via batch tests using VDI guideline 4630 is being conducted by approximately 40 different laboratories in Germany. Our results of methane yieldsshow relatively good agreement between laboratory testing and full-scale biogas plant. When the substrate input are measured well and the residual methane potential of the fermentation residue is measured, we have shown, that laboratory methane yields can be used for planning biogas plants. The biogas yield guidelines compiled by the German agencyKTBL based on laboratory values from several well-known biogas laboratories and institutes were shown to be accurate and appropriate for the preliminary economic planning of future biogas plants. In addition to the laboratory value of the specific methane yield, other parameters also play an important role in the planning of biogas plants (e.g. hydraulic retention time HRT, organic loading rate OLR, substrate mixture), and the accuracy of the measurement technology used (e.g. gas meter, gas quality determination, scales). Increasingly, laboratories are validating methane yield results through inter-laboratory testing. To ensure the accuracyof the laboratory tests for the determining methane yield, regular participation in these types of inter laboratory tests, along with laboratory internal validation using standard substrates, should become the standard practice to ensure highquality and replicable results.