Operational modeling of a sustainable gas supply chain

Biogas production from codigestion of cattle manure and biomass can have a significant contribution to a sustainable gas supply when this gas is upgraded to specifications prescribed for injection into the national gas grid and injected into this grid. In this study, we analyzed such a gas supply chain in a Dutch situation. A model was developed with which the cost price per m(n)(3) was presented as a function of scale level (m(n)(3)/hr). The hypothesis that transport costs increase with increasing scale level was confirmed although this is not the main factor influencing the cost price for the considered production scales. For farm-scale gas supply chains (approximately 150-250 m(n)(3)/h green gas), a significant improvement is expected from decreasing costs of digesters and upgrading installations, and efficiency improvement of digesters. In this study also practical sustainability criteria for such a supply chain were investigated. For this reason, the digestate from the digester should be used as a fertilizer. For larger scale levels, the number of transport movements and energy use in the supply chain seem to become a limiting factor with respect to sustainability.