An environment-economic analysis of hydrogen production using advanced biorefineries and its comparison with conventional technologies

Abstract This paper shows how novel high-performance thermophilic consortia employed in the dark fermentation stage of a biorefinery can lead to a competitive commercial-scale hydrogen production using lignocellulosic biomass as feedstock. The biorefinery design alternatives under study also include either diluted acid or hydrothermal pretreatment, and the option of either selling the biogas produced in the wastewater treatment stage or using it for electricity cogeneration. A bi-dimensional (i.e., environmental-economic) sustainability analysis was carried out comparing these four design alternatives against two conventional schemes (coal gasification and natural gas reforming). Results showed that, under a regulatory framework that considers environmental and economic issues on the same basis, the low total production costs of conventional schemes are not enough to compensate, in monetary terms, their severe environmental impacts (mainly water usage and pollution) when compared with the biorefining options. Moreover, most of the proposed biorefinery schemes ranked higher than conventional options. In particular, the design with acid pretreatment and biogas sale was the most sustainable option with a positive global sustainability indicator (0.007 USD/MJout).