Environmental Engineering Reference
In-Depth Information
10.3.6
GHG Control
In conclusion, by the year 2100, CH 4 ,N 2 O, and CFC may contribute about one-third to global
warming, with the remaining two-thirds being contributed by CO 2 . In regard to methane, efforts can
be made to limit its leakage from gas wells, transport pipelines, storage tanks, LNG tankers, coal
mines, and other sources of anthropogenic CH 4 . The production of anthropogenic N 2 O is poorly
understood; hence it will be difficult to control its emission. Because CFC production is being
phased out worldwide, it will eventually disappear from the atmosphere. The greatest technical
and economic problem will be the reduction of CO 2 emissions. This is the subject of the next
section.
10.4
CONTROLLING CO 2 EMISSIONS
Global warming can be ameliorated by reducing the emissions of CO 2 and other greenhouse gases
into the atmosphere. In this section we shall discuss the possibilities of slowing the build-up of
CO 2 concentrations in the atmosphere.
About 86% of the world's present primary energy usage comes from the consumption of
fossil fuels. Worldwide the energy consumption in general—and, concomitantly, fossil energy
consumption—is growing on the average by 1.5% per year (see Section 2.3). As fossil fuels will
become scarcer and more expensive to recover and other energy technologies become available,
the fossil fuel portion of the total energy consumption may become smaller. In the next decades,
however, we only can hope to ameliorate the rate of increase of global temperatures by slowing
down and then reversing the rate of growth of fossil energy consumption. Also, some technologies
are becoming available for capturing CO 2 from combustion sources and sequestering it in terrestrial
and deep ocean repositories. Emission reductions of CO 2 can be accomplished by a combination
of several of the following approaches:
End-use efficiency improvements and conservation
Supply side efficiency improvements
Capture and sequestration of CO 2 in subterranean reservoirs or in the deep ocean
Utilization of CO 2 for enhanced oil and natural gas recovery and for enhanced biomass
production (photosynthesis)
Shift to nonfossil energy sources.
10.4.1
End-Use Efficiency Improvements and Conservation
The simplest and most cost-effective approach to reducing carbon emissions is by end-use efficiency
improvements and conservation. In Chapter 2 we discussed various end-use measures that would
result in carbon emission reductions. In the residential-commercial sector, they range from lowering
the thermostat in the winter (less heating), raising it in the summer (less air conditioning), better
insulation, less hot water use, replacement of incandescent with fluorescent lighting, replacement
of electric clothes dryers with gas dryers, and so on. It is estimated that in the United States, in
 
 
 
 
 
 
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