New energy crop giant cane (Arundo donax L.) can substitute traditional energy crops increasing biogas yield and reducing costs

Abstract

Giant cane is a promising non-food crop for biogas production. Giant cane and corn silages coming from full-scale fields were tested, in mixtures with pig slurry, for biomethane production by a continuous stirred tank lab-scale-reactor (CSTR) approach. Results indicated that giant cane produced less biomethane than corn, i.e. 174±10Nm3CH4Mg−1TS−1 and 245±26Nm3 CH4Mg−1TS−1, respectively. On the other hand, because of its high field biomass production, the biogas obtainable per Ha was higher for giant cane than for corn, i.e. 12,292Nm3 CH4Ha−1 and 4549Nm3CH4Ha−1, respectively. Low energetic and agronomic inputs for giant cane cultivation led to a considerable reduction in the costs of producing both electricity and biomethane, i.e. 0.50€Nm−3CH4−1 and 0.81€Nm−3CH4−1, and 0.10€kWhEE−1 and 0.19€kWhEE−1 for biomethane and electricity production, and for giant cane and corn mixtures respectively.