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Operation, transportation and warehousing need energy for their activities, so
far mainly in form of electricity, fossil fuels and heat. They all have impacts on the
environment. A typical measure for this impact is the emission of carbon dioxide CO
2
from the combustion process. Carbon dioxide is the most common so-called greenhouse
gas (GHG). But other even more toxic gases have an influence on the global warming:
• Nitrogen oxides NO
x
.
• Nitrous oxide N
2
O.
• Methane CH
4
.
• Sulphur dioxide SO
2
.
• Non-methane hydro carbons NMHC.
• Particular matter PM (particle pollution).
In order to get a key performance indicator of the environmental impact the emission
of a transportation chain is expressed in terms of CO
2
e, carbon dioxide equivalents. It is
formed by the mass weights of carbon dioxide, methane and nitrous oxide:
CO
2
e = CO
2
+ 25 CH
4
+ 298 N
2
O
(6.1)
In a combustion process the main gas produced is carbon dioxide. However,
taking the weighting factors of methane and nitrous oxide into consideration, these
gases could also have a major influence on the environment.
Example 1:
A 40 feet container is transported from the city of Hamburg in the northern part
of Germany to the city of Dresden in the eastern part of Germany. The distance is about
470 km. The total emissions are given in Table 6.1.
Table 6.1 Emissions for the truck transport from Hamburg to Dresden
(calculation with [3])
Emission
Emission (kg)
Carbon dioxide
600
Nitrogen oxide
1.63
Sulfur dioxide
0.69
Non-methane hydro carbon
0.265
Particular matter
0.063
CO
2
e
620
Besides greenhouse gases, categories were determined for classifying the environmental
impact:
a. Resource consumption.
b. Land use.
c. Greenhouse effect.
d. Depletion of the ozone layer.
e. Acidification.
f. Eutrophication.
g. Eco-toxicity.