PSI - Issue 24

Francesco Del Pero et al. / Procedia Structural Integrity 24 (2019) 906–925 F. Del Pero et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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Table 3. GWP, PED and cost of reference and lightweight design solution

Use

Total

Materials

Production

ICEV

EV_EU28

EV_PL

EV_NO

ICEV

EV_EU28

EV_PL

EV_NO

GWP [kgCO 2 eq]

97.3

2.7

161.8

105.0

251.0

7.7

261.8

205.1

351.1

107.8

PED [MJ]

1110.0

66.5 32.4

2980.0 2730.0

3030.0 1250.0 4156.5

3906.5 4206.5 2426.5

Reference

23.0 71.1

82.7 90.5

30.3 58.8

22.7

21.5

138.1 163.7

85.7

78.1

76.9 77.5

Cost [€]

GWP [kgCO 2 eq]

2.1

140.0

4.3

132.0

213.2

PED [MJ]

1350.0

54.3 24.8

1670.0 1520.0

1690.0

698.0

3074.3

2924.3 3094.3 2102.3

Lightweight

64.0

45.3

16.9

12.7

12.0

134.1

105.7

101.5

100.8

Cost [€]

3.1. Comparison reference/lightweight variants The comparison reference/lightweight design solutions is carried out separately for the three assessment indicators. Global Warming Potential. Figure 1 shows the GWP percentage variation reference/lightweight solution for all the considered operation case studies; data are reported for both total value and single LC stages. Figure 2 illustrates the contribution analysis by LC stage of GWP basing on absolute impacts for the two alternatives. Figure 1 stresses that lightweight design allows achieving about 27 % GWP reduction in materials stage, which translates into 26.2 kgCO 2 eq absolute reduction (see Figure 2). This effect is mainly due to the material composition of the module: despite raw materials extraction and production processes of aluminum are by far more energy intensive with respect to steel, the lower amount of material used (44 % mass reduction) results in a lower impact of the lightweight module. Another relevant percentage GWP decrease occurs in production stage (about 22 %) but, considering that production provides a very low contribution to total impact (within the range 1-3 % depending on operation case study - see Figure 2), the absolute GWP saving is very low (0.6 kgCO 2 eq). Concerning use stage, the novel solution provides 44 % impact reduction for all the operation case studies: lightweighting involves a reduction of FC, which in turn allows achieving both impact reduction in fuel/energy supply chain and abatement of CO 2 exhaust air emissions. It has to be noted that The reason for this is that use stage impact has a linear proportionality with respect to mass for both ICEV and EV case studies (this rule applies also to PED indicator). On the other hand, the absolute use stage GWP strongly depends on propulsion technology and electricity grid mix: impact quota associated with operation is higher for EV_PL, ICEV and EV_EU28 where the energy is mainly from fossil resources, while it is lower for EV_NO where electricity is almost totally made from renewable resources. As a consequence, the percentage decrease in total GWP derives directly from the significance of the use stage for the different operation case studies, with higher values for EV_PL, ICEV and EV_EU28 (within the range 36-39 %) and lower benefit for EV_NO (28 %). The absolute GWP variation are 137.9, 97.3, 73.1 and 30.3 kgCO 2 eq respectively for EV_PL, ICEV, EV_EU28 and EV_NO.  the percentage benefit is unaltered passing from one propulsion technology to another  percentage reduction in GWP and mass are the same.