Page 201 - Materials Chemistry, Second Edition

EXERGY ANALYSIS AND ITS CONNECTION TO LIFE CYCLE ASSESSMENT 187

study is included in which LCA and ExLCA methods are applied to a complex
process: nuclear-based hydrogen production.

8.2 Life Cycle Assessment

LCA is a useful method for investigating the environmental impacts of a product
or process. It is a cradle-to-grave analysis in which not only the usage stage but
also other stages in the life of a product or process are taken into consideration,
such as production, transportation and disposal. LCA is used to determine and
assess overall environmental impacts and to define the most environmentally
critical phase in order to decrease the negative environmental effects of a prod-
uct or a process. LCA is also conducted to compare competing products or pro-
cesses and thereby identify which is more environmentally benign.
The International Standards of Organization (ISO) developed its 14000 series
for life cycle assessment, including several parts:

• ISO-14040, Life Cycle Assessment - Principles and Framework
(ISO, 1997)
• ISO-14041, Life Cycle Assessment - Goal and Scope Definition
and Inventory Analysis (ISO, 1998)
• ISO-14042, Life Cycle Assessment - Life Cycle Impact Assessment
(ISO, 2000)
• ISO-14043, Life Cycle Assessment - Life Cycle Interpretation
(ISO, 2000)
• ISO-14044, Life Cycle Assessment - Requirements and Guidelines
(ISO, 2006)

LCA consists of four main phases (Figure 8.1), which are explained further
in the following sections. Arrows in Figure 8.1 indicate that all phases of the
LCA are linked to each other. The life cycle interpretation is also linked to all
phases, since the phases of the LCA should be reviewed and necessary modifi-
cations made depending on the results of a LCA.

Goal and Inventory Impact Improvement
scope ΦΦ analysis ΦΦ assessment «= >
definition analysis
t t t t

Interpretation

Figure 8.1 Life cycle assessment framework, showing the main steps in LCA and the relations
between them.