The traditional pathway for biogas production consists in the anaerobic digestion of starchy and sugar biomass mainly from dedicated energy crops, needing agricultural land and heavy irrigation. A retrofitting of the existing biogas plants is proposed in order to reduce competition with food crops and to increase the sustainability of the whole chain in terms of land and water consumption; moreover the use of the lignocellulosic biomass is evaluated. The biomass after physical, chemical or biological pretreatment can be digested in a biogas plant to reduce the current diet without affecting the biogas production.

The present study analyzes the state of the art in the lignocellulosic biomass feeding into biogas plants and describes a preliminary techno-economical study of the pathway and the layout to be adopted, including the efficiencies and energy yields of the involved processes.