2011 International Conference on Alternative Energy in Developing Countries and Emerging Economies
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Examples of inputs and outputs quantities include inputs
of materials, energy, chemicals and other, outputs of air
emissions, water emissions or solid waste. Usually, life
cycle assessment inventories and modeling are carried out
using dedicated software packages. Depending on the
software package used, it is possible to model life cycle
social impacts in parallel with environmental life cycle.
The data must be related to the functional unit defined in
the goal and scope definition. Data can be presented in
tables and some interpretations can be made already at
this stage. The results of the inventory is an LCI which
provides information about all inputs and outputs in the
form of elementary flow from the environment from all
the unit processes involved in the study
.
C. Life Cycle Impact Assessment
The last step is life cycle impact assessment. It is
aimed at evaluating the contribution to impact categories
such as global warming, acidification, etc and including
the impacts in terms of emissions and raw material
depletion. The first step is characterization where impact
potentials are calculated based on the LCI results. The
next step is normalization which provides a basis for
comparing different types of environmental impact
categories (all impacts get the same unit). In weighting
step, a weighting factor to each impact category is
assigned depending on the relative importance. This step
is necessary to create a single indicator
.
In this paper, the authors decided to use a damage
approach, using SimaPro software based on the EDIP
method and the Ecoinvent Database [4-6]. This
methodology represents 18 different impact categories:
Global Warming 100 years, Ozone Depletion, Ozone
Formation (Vegetation), Ozone Formation (Human),
Acidification, Terrestrial Eutrophication, Aquatic
Eutrophication Nitrogen EP(N), Aquatic Eutrophication
Phosphorous EP(P), Human Toxicity Air, Human
Toxicity Water, Human Toxicity Soil, Ecotoxicity Water
Chronic, Ecotoxicity Water Acute, Ecotoxicity Soil
Chronic, Hazardous Waste, Slags/Ashes, Bulk Waste,
and Radioactive Waste. The EDIP method includes
characterization, normalization, and weighting. These
calculations is followed by,
(1)
Classification and Characterization
The inventory data is associated with specific
environmental impact categories and category indicators.
The characterization method in LCA is based on
scientific method drawn from environmental chemistry,
toxicology, ecology etc, for describing environmental
impacts and can be calculated using Eq (1).
¦
u
ij
i
j
EF Q
EP
(1)
Where
EP
j
is the environmental impact potential (kg
substance equivalent), Q
i
is the quantity of substance (kg
substance j), EF
ij
is an equivalency factor (kg substance
equivalent/ kg substance j).
(2)
Normalization
To indicate the share of the modeled, the results in
worldwide or regional total e.g. relating a product’s life
CO
2
emission to the average global are used.
Normalization is an optional element of LCIA according
to ISO 14044 and can be calculated using Eq (2).
j
j
j
ER T
EP
product
NP
u
u
1
)
(
(2)
Where NP
j(product)
is the normalized environment
impact potential (person), T is the lifetime of product
(year), ER
j
is the normalization reference (kg substance
equivalent/ person/year).
(3)
Weighting
The category indicator resuts can be weighted
including societal preference of the various impact
categories and can be calculated using Eq (3).
j
j
j
NP WF WP
u
(3)
Where WP
j
is the weighted environmental impact
potential (Person for target year: Pt.), WF
j
is the
weighting factor.
The parameters used in calculation are shown in Table
4.
TABLE
IV
P
ARAMETERS ON
EDIP
CALCULATION OF NORMALIZATION AND
WEIGHTING FACTOR
Impact
Categories
Unit (ER
j
)
(
j
ER T
1
u
)
Weighting
Factor
(WF
j
)
GW
kg CO
2
-
eq./kg/person/year
1.15E-04
1.1
OD
kg CFC-11-
eq./kg/person/year
9.71E+00
63
OF(V)
m
2
.ppm.h /
kg/person/year
7.14E-06
1.2
OF(H)
person.ppm.h /
kg/person/year
1.00E-01
1.2
Ac
m
2
/kg/person/year
4.55E-04
1.3
TE
m
2
/kg/person/year
4.76E-04
1.2
EP(N)
kgN/kg/person/year
8.33E-02
1.4
EP(P)
kgP/kg/person/year
2.44E+00
1
HTA
m
3
/kg/person/year
5.88E-09
1.1
HTW
m
3
/kg/person/year
1.69E-05
1.3
HTS
m
3
/kg/person/year
3.23E-03
1.2
EWC
m
3
/kg/person/year
0.00E+00
0
EWA
m
3
/kg/person/year
0.00E+00
0
ESC
m
3
/kg/person/year
0.00E+00
0
HW
kg/kg /person/year
4.83E-02
1.1
S/A
kg/kg/person/year
2.86E-03
1.1
BW
kg/kg/person/year
7.41E-04
1.1
RW
kg/kg/person/year
2.86E+01
1.1
Source: EDIP 2003 V1.02 Method, SimaPro Software 2007 [7]
