Page 20 - Materials Chemistry, Second Edition

Importance of Life Cycle Assessment 5

approach: both approaches differ with respect to system delimitation and the use of
average versus marginal data. Attributional LCA describes the environmentally
relevant physical flows to and from a life cycle and its subsystems, while conse-
quential LCA describes how environmentally relevant flows will change in
response to possible decisions. Marginal data are represented by the product,
resource, supplier, or technology, which are the most sensitive to changes in
demand, and economic value criteria are used to identify the marginal products
(Ekvall and Weidema 2004).
Attributional LCA is limited to a single full life cycle from cradle to grave, and
consequential LCA is not limited to one life cycle, but uses system enlargement to
include the life cycles of the products affected by a change in the multifunctional
processes will often be handled through allocation, physical flows in the central
life cycle. In attributional LCA multifunctional processes will often be handled
through allocation, while in consequential LCA, allocation will generally be
avoided through the system expansion. Additionally, marginal data are used,
whereas average data are applied in attributional LCA (Ekvall and Weidema 2004;
Reinhard and Zah 2011).
Various scientists have employed LCA on renewable energy production sys-
tems (Reinhard and Zah 2011; Biswas et al. 2011; Ribeiro and Silva 2010;
Gabrielle and Gagnaire 2008; Gnansounou et al. 2009; Kiwjaroun et al. 2009;
Martínez et al. 2009; Suri et al. 2007; Laleman et al. 2011; Zah et al. 2007), and
some useful results considering the factors (e.g., biomass, technologies, use, sys-
tem boundary, allocation, reference system) affecting the outcome of the analysis
have been obtained (Singh et al. 2010).

4 Importance of Life Cycle Assessment

The purpose of LCA is to compile and evaluate the environmental consequences of
different options for fulfilling a certain function (Guinée 2004), and it is a uni-
versally accepted approach of determining the environmental consequences of a
particular product over its entire production cycle (Pant et al. 2011). The LCA
methodology can be useful to acquire a comprehensive knowledge of the envi-
ronmental impacts generated by industrial products during their whole life cycle
(de Eicker et al. 2010). LCA can play a useful role in public and private envi-
ronmental management in relation to products as this may involve both an envi-
ronmental comparison between existing products and the development of new
products (Guinée 2004). LCA has been the method of choice in recent years for
various kinds of new technologies for bioenergy and carbon sequestration.
The ‘‘holistic’’ nature of LCA depicts both its major strength and, at the same
time, its limitation. The broad scope of analyzing the complete life cycle of a
product can only be achieved at the expense of simplifying other aspects (Guinée
2004). LCA of renewable energy production system requires a careful design
regarding the goal and scope definition, choice of functional unit, reference