X-Message-Number: 31537
From: David Stodolsky <>
Subject: More is lost than gained when prioritizing biomass or land fo...
Date: Sun, 22 Mar 2009 14:27:05 +0100

<http://www.ki.ku.dk/Begivenheder/Begivenhedssamling/karstenhedegaard/>

CCAR Seminar: Karsten Hedegaard (COWI)
"Life Cycle Assessment of an Advanced Bioethanol Technology in the  
Perspective of Constrained Biomass Availability"

Among the existing environmental assessments of bioethanol for  
transport, the studies suggesting an environmental benefit of  
bioethanol all ignore the constraints on the availability of biomass  
resources and the implications competition for biomass has on the  
assessment. As shown in the presentation, toward 2030, regardless of  
whether a global or European perspective is applied, the amount of  
biomass, which can become available for bioethanol or other energy  
uses, will be physically and economically constrained. This implies  
that use of biomass or land for bioethanol production will most likely  
happen at the expense of alternative uses. Since natural gas and coal  
will be used as fuels for heat and power production at least within  
this time frame, the lost alternatives include substitution of natural  
gas or coal in the heat and power sector. In a case study, the  
environmental feasibility of using advanced fermentation based  
bioethanol for transport is investigated, when held up against the  
consequence of losing alternative biomass utilizations. The biomass  
feedstock considered is an energy whole-crop in the form of whole-crop  
maize and the bioethanol technology considered includes fermentation  
of lignocellulosic biomass. In the presentation, it is shown that for  
the case of this advanced bioethanol technology, in terms of reducing  
greenhouse emissions and fossil fuel dependency, more is lost than  
gained when prioritizing biomass or land for bioethanol. Technology  
pathways involving heat and power production and/or biogas, natural  
gas or electricity for transport are advantageous. This is mainly  
caused by the significant energy conversion losses in bioethanol  
production compared to use of biomass in the energy sector. The losses  
lie in the need for pretreatment (lignocellulosic based production),  
the relatively low fermentation yield of ethanol, the need to dry and  
further process the byproduct and residual unconverted matter in order  
to make use of them, and the need to separate ethanol and water,  
implying distillation.



David Stodolsky
  Skype: davidstodolsky

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