Page 280 - Materials Chemistry, Second Edition

A Comparison of Life Cycle Assessment Studies 271

needed and special emphasis should be given to options that help mitigate risks
and create positive effects and co-benefits (UNEP/GRID-Arendal 2011).
Responding to these challenges effectively requires a life cycle perspective of the
biofuel production pathway/system. Since biofuels are considered a major alter-
native for the future energy demands, several LCA studies were carried out for the
enhancement of biofuel production system (Muys and Quizano 2002; Kim and
Dale 2009; Chiaramonti and Racchia 2010; Dressler et al. 2012). If biofuels are to
become a major alternative to petroleum, it has to be both environmentally and
economically advantageous. LCAs of these transitions will require much stronger
integration between economists and systems engineers to address what happens
during the transition phase when large-scale changes occur in many components of
a complex, market driven, technological system (McKone et al. 2011). To achieve
the target as per EC Directive 2009/28/EC (EC 2008), i.e., GHG savings of 60 %
by 2020, selection of feedstock for considering local factors and land utilization,
process technology, and consumption perspective are major steps to be considered
under LCA for improvement in production system. LCA studies conducted in the
recent past reported the process phases that can be improved by advancing the
technology to consider a product as biofuel according to European Directive 2009/
28/EC (Watson et al. 1996; Kaltschmitt et al. 1997; CONCAWE 2004; Larson
et al. 2006; Larson 2006; Korres et al. 2010). A generalized scheme for LCA of
biofuel production is presented in Fig. 1.
By the LCA study of energy crops, Emmenegger et al. (2011) concluded that
producing biofuels can reduce the fossil fuel use and GHG emissions when
compared to a fossil reference. The focus on GHG emissions of the main regu-
latory schemes neglects other relevant environmental impacts and may provide the
wrong incentives. Thus, water consumption may become a major concern, off-
setting the benefits of biofuel use with respect to climate change. McKone et al.
(2011) explained the following seven grand challenges that must be confronted to
enable LCA to effectively evaluate the environmental footprint of biofuel
alternatives.

(a) understanding farmers, feedstock options, and land use
(b) predicting biofuel production technologies and practices
(c) characterizing tailpipe emissions and their health consequences
(d) incorporating spatial heterogeneity in inventories and assessments
(e) accounting for time in impact assessments
(f) assessing transitions as well as end states
(g) confronting uncertainty and variability
Dressler et al. (2012) conducted LCA study of biogas from maize at three
different sites and find a variation in results due to local factor suggesting con-
sideration of local and regional factors before selecting energy crops. In a study
with biofuel from grass, Korres et al. (2010) consider that agronomy and digester
use are the biggest issues for controlling the GHG savings.