Consideration of the sustainability of biomass to bio­energy programs based on utilizing lignocellulosic feed­stocks is both timely and important in terms of the current plans for commercial valorization of this sector (Third International Conference on Lignocellulosic Ethanol; http: / /www. biofuelstp. eu/events/3rd-icle-

april-2013.pdf). Sustainability of second-generation bio­energy is also been driven and supported by European and International directives and certification programs, including the Renewable Energy Directive 2009/28/EC (EU-RED), International Sustainability and Carbon Cer­tification programs and standards, the Roundtable on Sustainable Biofuels and the Global Bioenergy Partner­ship (Scarlat and Dallemand, 2011). The sustainability of biomass to bioenergy programs has been a subject of great interest in Sweden, Canada and the western United States as well as in some Asian countries (Nguyen et al., 1999, 2000; Wu et al., 1999). The ecolog­ical and sustainable potential of biomass sources for fuel production is estimated to reach 130 TWh/year in Sweden by around 2020 (Parrika, 1997). Issues such as land use, environmental impact, logistics and resource management must be considered in terms of feedstock production. In addition, the sustainability of the biocon­version process(es) and downstream outputs, and the ability to meet REN and GHG emission targets must be carefully evaluated. High on the priority list of most national governments is the need to support rural development and sustain the local and national econo­mies. Consequently, biomass to bioenergy programs need to be subjected to detailed life cycle analysis (LCA), where all of the aforementioned considerations are evaluated. LCA can also help derisk biomass to bio­energy processes (Buonocore et al., 2012). The use of conventional crops for energy use can also be expanded, with careful consideration of land availability and food demand. For sustainable bioenergy development ligno — cellulosic crops (both herbaceous and woody) could be produced on marginal, degraded and surplus agricul­tural lands and, in theory, could provide the bulk of the biomass resource in the medium term along with aquatic biomass (algae) as a significant contribution in the longer term (Richardson, 2008). However, significant progress needs to be made to scale-up algal production and processing in an economic manner to make algal biomass to bioenergy a commercially viable option.

First-generation biofuels face both social and environ­mental challenges, largely because they use food crops that could lead to food price increases and possibly indi­rect land use change (ILUC). Nonfood biomass, e. g. lignocellulosic feedstocks such as organic wastes, forestry residues, high-yielding woody or grass energy crops and algae have the potential to provide possible solution to this problem, if developed and managed in a sustainable manner. The use of these feedstocks for second-generation biofuel production would signifi­cantly decrease the potential pressure on land use, improve GHG emission reductions when compared to some first-generation biofuels, and result in lower envi­ronmental and social risks (Bauen et al., 2009 IEA Report).

The environmental impacts of conventional crop pro­duction have been researched in far greater detail than those of lignocellulosic crop production. Technically, the potential supply of energy from lignocellulosic biomass depends largely on the amount of land that is available for growing energy crops. In parallel, the need to meet the growing worldwide demand for food, protect biodiversity, manage soil and water re­serves sustainably and fulfill additional socioeconomic objectives must be addressed. Bioenergy crop produc­tion can have positive impacts, for example, it can help to improve the soil structure and fertility of degraded lands. However, conversion of areas with sparse vegeta­tion to high-yielding lignocellulosic plantations or ILUC may lead to substantial reductions in ground water recharge and water supply, which may lead to deterio­rating conditions in water-scarce areas (Upham et al., 2011; Cabral et al., 2010; Smeets and Faaij, 2010). The cultivation of short rotation biomass crops may lead to nutrient removal or depletion (van den Broek et al.,

2000) , and important habitats may be lost through both land conversion and intensification (Pedroli et al., 2012). Aesthetic considerations also need to be consid­ered in terms of the impact of cultivating and harvesting short rotation bioenergy crops (Hardcastle, 2006). Sound agricultural methods exist that can achieve major in­creases in feedstock productivity in neutral or positive environmental conditions in order to provide a contin­uous supply of energy crops/biomass waste, which can support the important role of bioenergy chains in socioeconomic development (Figure 2.3; Dornburg et al., 2008). The issue of biomass logistics is also a factor that needs careful consideration in terms of feedstock supply, processing technology selection, sitting of com­mercial production facilities and overall sustainability (Stephen et al., 2010).

Recent studies have shown the potential of recycled wastewater for biomass production in an integrated nat­ural water treatment approach (Fedler and Duan, 2011), which suggests that through innovative and careful consideration of environmental impacts solutions can be found that have multiple potential benefits. It has been suggested that the application of strict sustainabil­ity criteria, standards and a requirement for certification (Scarlat and Dallemand, 2011; Schubert and Blasch, 2010; van Dam et al., 2010) of feedstocks, land use and

bioenergy programs globally could both alleviate concerns and provide a more harmonized framework globally for sustainable development of second — generation bioenergy (Cornelissen et al., 2012; Van Stappen et al., 2011).