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In this paper the suitability of three perennial, herbaceous, lignocellulosic grasses ( Arundo donax , Saccharum spontaneous spp. aegyptiacum and Miscanthus x giganteus ) for the production of second-generation bioethanol in semi-arid Mediterranean environment was studied. Crops were established in spring 2002, supplying irrigation and nitrogen fertilization up to 2004/2005 growing season. Subsequently, crops were grown without any agronomic input and harvested annually. Data reported in this paper refers to 2008/2009 and 2009/2010 growing seasons. Aboveground dry matter (DM) yield was higher in Arundo (35.4±2.1 Mg ha –1 in 2009 and 32.2±1.9 Mg ha –1 in 2010 harvest) than in Saccharum (27.3±2.0 and 23.9±1.9 Mg ha –1 , respectively) and Miscanthus (19.6±2.8 and 17.2±1.6 Mg ha –1 , respectively). Structural polysaccharides of the raw material were higher in Miscanthus (63.4% w/w) followed by Saccharum (61.5% w/w) and Arundo (57.6% w/w). The same trend was identified for the cellulose content (41.0%, 36.8% and 34.6%, respectively). The highest values in the total hemicellulose complex were observed in Saccharum (24.7%), followed by Arundo (23.1%) and Miscanthus (22.4%). The composition of structural polysaccharides leads to a higher theoretical ethanol yield (TEY) from one dry ton of Miscanthus feedstock (kg DM Mg –1 ), followed by Saccharum and Arundo . On the other hand, the TEY per unit surface (Mg ha –1 ) was greater in Arundo than in Saccharum and Miscanthus . When compared to other lignocellulosic sources used in the second-generation bioethanol technology, such as agricultural residues, woody species and other herbaceous perennial crops, Arundo , Saccharum and Miscanthus showed a great potential in terms of TEY ha –1 . Given the high levels of biomass yield and composition of structural polysaccharides, the three species might be introduced into the Mediterranean cropping systems to supply lignocellulosic biomass for second-generation industrial plants or bio-refineries.

Bioenergy crops are expected to play an important role in reducing CO2 emission, in energy supply and in European energy policy. However, a sustainable bioenergy supply must be resilient to climate change and the impacts on agriculture at both global and regional scale. The purpose of this study was to forecast the potential distribution of several bioenergy crops based on agronomic and environmental constrains under current conditions and future scenarios (2020 and 2030) in European Union. Potential biomass yield, according to the category end use product achievable in each environmental zone of Europe at present and in the future available land have been also studied. Future yields were assessed according to two factors: technological development and climate change: the former was based on prospect of DG-Agriculture for conventional crops and expert judgments for bioenergy crops, while the latter based on relevant research papers and literature reviews which used site-specific crop growth models. Yields are expected to increase in northern Europe due to climate change and technological development, while in southerneastern Europe the negative effect of climate change will be mitigated by the technological development. The estimated total biomass production in Europe, on the basis of future yields and surplus land made available for energy crops, may not be sufficient to meet the needs of bioenergy supply as claimed in the European directive 2009/28/EC.