Biogas potential density in four different scenarios.

<p>Panel (a) shows the base case with production 0.7 EJ/year (see parameters in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0171001#pone.0171001.t004" target="_blank">Table 4</a>). Panel (b) shows that the potential is substantially increased (to 1.1 EJ/year) if drier substrate mixtures are allowed. Panel (c) shows that increasing the minimal C:N ratio of the substrate mixture from 10 to 14 severely diminishes the potential (to 0.1 EJ/year), all other things equal. However, as shown in panel (d), the extra carbon can be supplied (by crop residues) if 25% DM content is allowed, and in this case the potential is 0.9 EJ/year.