Here we move up in scale. Argonne National Laboratory, working with the U. S. Department of Energy, has developed a model (GREET) to evaluate energy and emissions associated with vehicle life. Table 7.9 lists the
|
Table 7.9 Material content of a conventional family car and one made of lightweight materials |
|||
|
Material |
Conventional ICE vehicle, kg |
Lightweight ICE vehicle, kg |
Material energy Hm MJ/kg* |
|
Carbon steel |
839 |
254 |
32 |
|
Stainless steel |
0.0 |
5.8 |
81 |
|
Cast iron |
151 |
31 |
17 |
|
Wrought aluminum (10% recycle content) |
30 |
53 |
200 |
|
Cast aluminum (35% recycle content) |
64 |
118 |
149 |
|
Copper/brass |
26 |
45 |
72 |
|
Magnesium |
0.3 |
3.3 |
380 |
|
Glass |
39 |
33 |
15 |
|
Thermoplastic polymers (PU, PVC) |
94 |
65 |
80 |
|
Thermosetting polymers (polyester) |
55 |
41 |
88 |
|
Rubber |
33 |
17 |
110 |
|
CFRP |
0.0 |
134 |
273 |
|
GFRP |
0.0 |
20 |
110 |
|
Platinum, catalyst (Table 6.3) |
0.007 |
0.003 |
117000 |
|
Electronics, emission control etc (Table 6.4) |
0.27 |
0.167 |
3000 |
|
Other (proxy material: polycarbonate) |
26 |
18 |
110 |
|
Total mass |
1361 |
836 |
|
*From the data sheets of Chapter 12 and Tables 6.3 and 6.4. |
bill of materials for two of the vehicles they analyze: a conventional midsized family car with an internal combustion engine (ICE) and a vehicle of similar size made of lightweight materials, with the biggest differences italicized in bold. The total mass is shown at the bottom of the columns. "Lightweighting" reduces it by 39%.
The data sheets of Chapter 12 provide the embodied energies of the materials. Fuel consumption scales with weight in ways that are analyzed in Chapter 9; for now we use the results that a conventional car of this weight consumes 3.15 MJ/km; the lighter one consumes 2.0 MJ/km.1 There is enough information here to allow an approximate comparison of embodied energy and the use of the two vehicles, assuming both are driven 25,000 km per year for 10 years.
The bar charts of Figure 7.11 show the comparison. The input data are of the most approximate nature, but it would take very large discrepancies to change the conclusion: the energy consumed in the use phase of both vehicles greatly exceeds that embodied in their materials. The use of lightweight materials increases the embodied energy by 43% but reduces the much larger fuel-energy consumption by 37%. The result is a net gain: the sum of the material and use energies for the lightweight vehicle is 30% less than that of the conventional one.
8 X 105
0
FIGURE 7.11
family car.
T MJ/km = 2.86 liters/100 km = 95.5 miles per U. K. gallon = 79.5 miles per U. S. gallon.
