Page 199 - Materials Chemistry, Second Edition

8

Exergy Analysis and its Connection to Life
Cycle Assessment

Marc A. Rosen, Ibrahim Dincer and Ahmet Ozbilen

Faculty of Engineering and Applied Science,
University of Ontario Institute of Technology,
Oshawa, Ontario, Canada
Emails: marc.rosen@uoitxa, Ibrahim.Dincer@uoit.ca, Ahmet.Ozbilen@uoit.ca

Abstract
Exergetic life cycle assessment (ExLCA) is described, as is the thermodynamic quan-
tity exergy that underpins this variation on life cycle assessment (LCA). Life cycle
assessment is an analytical tool to identify, quantify, and decrease the overall environ-
mental impact of a system, process, or product, and ExLCA has similar objectives, but
a different approach. The differences between ExLCA and LCA are highlighted, and
the extension of LCA to ExLCA is explained.
A case study is utilized to illustrate the application and benefits of exergetic life
cycle assessment. The case study involves an environmental assessment of nuclear-
based hydrogen production. The particular process considered is an advanced hydro-
gen production process which is under development, driven by nuclear energy and
based on thermochemical water splitting using a copper-chlorine (Cu-Cl) cycle. Exergy
efficiencies and air pollution emissions are evaluated for all process steps, including
uranium processing, nuclear plant operation, and hydrogen production. LCA results
are presented in four key categories: acidification potential, eutrophication potential,
global warming potential, and ozone depletion potential. The ExLCA results indicate
that the greatest irreversibility is caused by uranium processing. A parametric study is
also performed for a variety of plant lifetimes.

Keywords: Exergetic life cycle assessment, exergy, sustainability, environment,
hydrogen production

8.1 Introduction

As awareness of environmental concerns increases, society has become
increasingly worried about issues such as natural resource depletion and
environmental degradation. Business and industry have responded to this

Mary Ann Curran (ed.) Life Cycle Assessment Handbook: A Guide for Environmentally
Sustainable Products, (185-216) © 2012 Scrivener Publishing LLC

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