second generation biofuel - Second Generation Biofuels: An...

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Second Generation Biofuels: An Unproven Future Technology with Unknown Risks By Helena Paul and Almuth Ernsting What are second generation biofuels? In this paper, we refer to second generation biofuels as meaning biomass-to-liquid technologies, namely cellulosic ethanol and Fischer-Tropsch gasification, which are intended to use lignocellulosic biomass. Those technologies are not yet commercially available. Some companies refer to certain agrofuel technologies which use existing feedstocks like palm oil or rapeseed oil as ‘second generation’ (for example Neste Oil’s NExBTL diesel, which uses high-pressure hydrogenation of fatty acids). Can second generation biofuels play a role in mitigating climate change? Any technology which can help to mitigate climate change must a) Have the potential to become commercially available on a large scale within the next 5-8 years: Unless we begin to reduce global emissions and introduce technologies and policy measures which can help us shift to a low-carbon society within that period, a mass extinction event may become unavoidable. [see: “Global temperature change”, James Hansen et al, PNAS, 26 th September 2006] ; AND b) Be proven to have the potential for large-scale emissions reductions, once life-cycle emissions of all greenhouse gases have been considered, not just at the micro-level, but at the global level. If a technology, directly or indirectly, destroys ecosystems which play an essential role in the Earth’s carbon cycle, then it risks accelerating, not mitigating global warming. As we show below, there is evidence that second generation biofuels satisfy neither of these criteria. When will second-generation biofuels become commercially available? Cellulosic ethanol: The only commercial cellulosic ethanol refinery is run by Iogen Corporation in Ottawa. It uses more energy than it produces, and, in terms of energy use and output, performs considerably worse than first-generation corn ethanol. The different processes needed to refine cellulosic ethanol, including pre-treatment and distillation, are extremely energy-intensive. The United States Department of Environment are funding research into cellulosic ethanol, and they have identified significant ‘biological barriers’ which need to be overcome if cellulosic ethanol is to become a viable option. [Fuel Ethanol Production, DEO, Genomics:GTL, http://genomicsgtl.energy.gov/biofuels/ethanolproduction.shtml#improve ] Enzymes can break down cellulose, but they cannot do so efficiently and they can only produce a very dilute mixture which is then distilled into ethanol. Making cellulosic ethanol viable is not a matter of scaling up existing technology and gradually improving efficiency gains: Firstly, scientists will have to better understand plant physiology and the mechanisms which prevent cellulose from being broken down by fungi and microbes. This will require some major scientific breakthroughs. Secondly, scientists will have to either find or, more likely, genetically engineer microbes or fungi which can
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This note was uploaded on 09/13/2011 for the course SOCIAL SOCIALWORK taught by Professor Staff during the Spring '09 term at University of Nevada, Las Vegas.

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second generation biofuel - Second Generation Biofuels: An...

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