Biofuels and sustainability

Abstract

Interest in liquid biofuels production and use has increased worldwide as part of government policies to address the growing scarcity and riskiness of petroleum use, and, at least in theory, to help mitigate adverse global climate change. The existing biofuels markets are dominated by U.S. ethanol production based on cornstarch, Brazilian ethanol production based on sugarcane, and European biodiesel production based on rapeseed oil. Other promising efforts have included programs to shift toward the production and use of biofuels based on residues and waste materials from the agricultural and forestry sectors, and perennial grasses, such as switchgrass and miscanthus--so-called cellulosic ethanol. This article reviews these efforts and the recent literature in the context of ecological economics and sustainability science. Several common dimensions for sustainable biofuels are discussed: scale (resource assessment, land availability, and land use practices); efficiency (economic and energy); equity (geographic distribution of resources and the "food versus fuel" debate); socio-economic issues; and environmental effects and emissions. Recent proposals have been made for the development of sustainable biofuels criteria, culminating in standards released in Sweden in 2008 and a draft report from the international Roundtable on Sustainable Biofuels. These criteria hold promise for accelerating a shift away from unsustainable biofuels based on grain, such as corn, and toward possible sustainable feedstock and production practices that may be able to meet a variety of social, economic, and environmental sustainability criteria.

Disponibilidad y costos de producción de biomasa forestal como materia prima para la producción de bioetanol

“…Una alternativa viable y usada desde hace varios años es la biomasa forestal la cual puede contribuir a reducir la dependencia de combustibles fósiles mediante la conversión de energía en sus diferentes formas como combustible para el transporte (Wyman, 1999;2003;Perlack et al, 2005). Las características importantes de la biomasa vegetal, o la parte fibrosa y generalmente no comestible de los tallos, ramas y raíces de las plantas, son la abundancia, su capacidad de renovación y la contribución en la reducción de la emisión de gases efecto invernadero (Kim and Dale, 2005;Wang, 2005;Solomon et al, 2007;Solomon, 2010) 1 . Sus principales componentes, la celulosa y hemicelulosa, son azúcares que se pueden usar para producir etanol a través de hidrólisis y fermentación (USDE, 2006).…”

Improved saccharification and ethanol yield from field-grown transgenic poplar deficient in cinnamoyl-CoA reductase

“…Second-generation biofuels derive from lignocellulosic biomass in dedicated energy crops (poplar, switchgrass, Miscanthus sp., and others) that can be grown on marginal lands with less fertilizer for multiple annual cycles, or from the currently underused lignocellulosic residues from crop plants, such as corn, wheat, and sugarcane bagasse. Therefore, the energy output and carbon savings are expected to be much higher than those of first-generation biofuel crops (1,2). However, the polysaccharides in lignocellulosic biomass are not readily enzyme-accessible mainly because of the presence of lignin.…”

Direct conversion of plant biomass to ethanol by engineered Caldicellulosiruptor bescii

“…tation of global petroleum reserves, and the impact on climate change induced by greenhouse gases have increased the need for renewable and sustainable biofuels (1)(2)(3)(4)(5). First-generation biofuels produced from food crops, such as corn, are limited by cost and competition with food supply (6,7).…”