Geoscience Reference
In-Depth Information
45
40
Global
US
35
30
25
20
15
10
5
0
Coal
Oil
Natural Gas
Other
Figure 23.
Sources of CO 2 emissions, 2010. This fi gure shows the percentage break-
down of CO 2 emissions in 2010 for all countries (left bars) and for the United States
(right bars).
• Petroleum emits 0.9 tons of CO 2 per $1,000 of fuel.
• Natural gas emits 2 tons of CO 2 per $1,000 of fuel.
• Coal emits 11 tons of CO 2 per $1,000 of fuel.
The results are striking: Coal has about six times more CO 2 emissions
per dollar of cost than natural gas and about twelve times more than
petroleum. Coal is a very inexpensive fuel per unit of energy but it has
the disadvantage that much CO 2 is released per dollar of expenditure. 3
The economics of emissions shown in the list above has important
implications. It suggests that the most economical way to reduce energy
emissions is to reduce coal use. This implication is not proven by the bul-
leted numbers because it requires further economic analysis of the capital
and labor costs involved in using different fuels. However, this prelimi-
nary result survives the most careful scrutiny, as we see in the next sec-
tion. This point deserves repetition because it is so critical: The most
 
 
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