Environmental Engineering Reference
In-Depth Information
1200
974
1000
800
600
469
400
200
46
39
15
18
14
15
0
fig. 10.2
Comparison of life-cycle emissions in metric tonnes of
CO
e per GW-hour for various modes of electricity production.
(Sources of data:[
,
,
])
showed the
flow of energy into the generating system and
the
flow of electricity out. From it you can
nd that:
Only
% of the primary energy in the fuel gets trans-
formed into electricity;
Of that, some of the electricity is used inside the power
plants, some is lost along the way in the distribution
system, so only about
% of the fuel energy reaches
the consumers in the form of electricity;
Gas is better than coal
% of the energy in gas is
turned into electricity, but only
-
% for coal.
The emissions in electrical generation depend on the
fuel used in the power plant. I often get questions when
talking about low- or zero-emission sources of power
about what happens if I include the emissions in manu-
facturing the power plant as well as the emissions from its
operation. The answer is in
Figure
which shows the
life-cycle emission per gigawatt-hour of electrical output
.
