Page 263 - Design for Environment A Guide to Sustainable Product Development

Transportation Industries 239

FIGURE 12.2 Life-cycle environmental burdens due to production and use of
motor vehicles [4].

greenhouse gas emissions are dominated by the vehicle use stage,
whereas the largest contributions to waste and emissions occur in the
materials acquisition stage. The contributions of the actual manufac-
turing stage are relatively small, since much of the final production
involves assembly operations [4].
One of the most direct strategies for reducing energy consump-
tion during vehicle use is the use of lighter-weight materials such as
aluminum. For example, industry studies have shown that in auto-
motive applications each kilogram of aluminum replacing mild steel,
cast iron, or high strength steel saved between 13 and 20 kilograms of
greenhouse gas emissions depending on the component. For metro
or subway cars, the avoided GHG emissions are approximately 26
kilograms in Europe and 51 kilograms in the United States. [5].
There are numerous examples of DFE initiatives in the transporta-
tion industries that address energy and environmental goals at vari-
ous points in the life cycle. The following are selected highlights, but
there are many more similar stories of innovation:

• General Electric is designing a hybrid diesel-electric locomo-
tive that will capture the energy dissipated during braking
and store it in a series of sophisticated batteries. That stored
energy can be used by the crew on demand—reducing fuel
consumption by as much as 15 percent and emissions by as
much as 50 percent compared to most of the freight locomo-
tives in use today. In addition to environmental advantages,
a hybrid will operate more efficiently in higher altitudes and