Proceedings Venice 2012, Fourth International Symposium on Energy from Biomass and Waste San Servolo, Venice, Italy; 12-15 November 2012  2012 by CISA Publisher, Italy ANAEROBIC DIGESTION OF ALTERNATIVE ENERGY CROPS M. GRIGATTI*, L. BARBANTI*, G. DI GIROLAMO*, L. CAVANI*, L. BERTIN** AND C. CIAVATTA* * DipSA - Department of Agricultural Science, University of Bologna, Viale G. Fanin, 40, 40127 Bologna, Italy. ** DICAM - Department of Civil, Environmental and Materials Engineering, University of Bologna, via Terracini 28, 40131 Bologna, Italy. SUMMARY: Biomass crops deserve increasing interest among renewable energy sources. In this work we tested the biomass produced by Arundo, Switchgrass and two sorghum hybrids (B 133 and Trudan Headless), all grown without irrigation at moderate fertilization level, compared to irrigated, well fertilized Maize. The methane yield of the five crops was assessed in a batch experiment at 0.5 % VS organic load, incubated over 47 days at 35 °C. B 133 showed the highest dry biomass yield (29.2 Mg ha -1 ), followed by: Arundo, Switchgrass and Trudan Headless (26.8, 22.4 and 20.8 Mg ha -1 , respectively); Maize achieved 27.8 Mg ha -1 . Switchgrass showed the highest methane yield, 246 ml g -1 VS, followed by Trudan Headless, B 133, and Arundo (230, 193, 175 ml CH 4 g -1 VS, respectively); Maize exhibited an intermediate yield (192 ml CH 4 g -1 VS). Overall, the five crops displayed a remarkable methane yield; more specifically, the four annual and perennial biomass crops offer a promising alternative to Maize, achieving comparable biomass and methane yields in exchange for a lower need of cropping inputs. 1. INTRODUCTION The continuous increase in fossil fuel prices following the global oil stock decrease, associated with the need to comply with the expected reduction of green house gases (GHGs) originating the ongoing climate change, strongly promoted alternative energy sources in the latest years (IEA, 2010). In this frame, bio-energy is likely to fill a significant part of this emerging energy gap, representing also an important strategy to reduce GHG emissions, complying with the Kyoto Protocol targets (EU directive 2009/28/EC). Many are the renewable energy sources based on the transformation of agricultural products, leading to bio-fuels, heat and power, etc. Among them, anaerobic digestion can successfully be used for biogas production which is recognized to be most energy efficient (Petersson et al., 2007). This reflected on the six-fold biogas production increase in the European Union in the latest fifteen years, reaching 7.5 million tons of oil equivalents in 2008 (Murphy et al., 2011). Anaerobic digestion for biogas production can be applied to many agricultural sources including crops, market and organic wastes. Despite this in recent years dedicated biomass crops, especially maize, increased their weight as feedstocks for bioethanol and biogas production