26.08.2015   ACCELERATOR DRIVEN SUBCRITICAL REACTORS

Energy policies

Anthropic CO2 emission amounted, in 2000, to 24 Gigatons.[3] The regional emissions of polluting agents and greenhouse gases are summarized in table 2.4 [27].

The comparison between emissions from different countries, apparent in table 2.5, is instructive and gives a measure of the effort which these countries will have to achieve in order to improve the situation [28].

S1000

S750

S650

 

Figure 2.3. Evolution of anthropic CO2 emission annual rates for different scenarios. The curves are labelled by the asymptotic value reached shown in figure 2.4. Solid lines and dashed lines correspond to two emission profiles which lead to the same final concentration [25].

 

image003

Figure 2.4. Evolution of CO2 concentrations corresponding to the emission profiles shown in figure 2.3 [25].

 

image004

Table 2.4. Emission rates of main polluting agents in different regions.

Carbon

Sulfur

Nitrogen

(Gtons)

(Mtons)

(Mtons)

North America

1.55

12.1

5.5

Latin America

0.26

3.2

1.4

Western Europe

1

10.4

3.7

Central Europe

0.25

3.9

1.0

CIS

1.08

12.4

4.0

Arab countries

0.22

2.2

1.0

Black Africa

0.11

1.9

0.7

South Asia

0.2

3.4

1.1

Pacific

1.27

15.1

5.7

Total

5.94

64.6

24.1

Countries showing CO2 emission

rates of more than 10 tons per capita

rely heavily on fossil fuels for electricity production. Other developed coun-

tries, usually, have large hydroelectric resources. This

is the case of the

Nordic countries and of Switzerland.

France is characterized by extensive

use of nuclear power, while Japan uses a relatively very small proportion of coal among the fossil fuels. The small emission of China, and other big countries like India, reflect their degree of development. Note that a large part of greenhouse gas emissions is due to transportation systems.

Table 2.5. Per capita emissions

of main polluting agents for different countries.

CO2

SO2

no2

(tons per capita)

(kg per capita)

(kg per capita)

Norway 7.5

12

55

Switzerland 7.1

10

28

Sweden 7.0

20

45

Netherlands 12.5

14

37

France 7.0

20

30

Canada 17.0

140

70

Poland 14.0

70

30

UK 11.0

68

49

Germany 13.0

70

40

USA 20.0

85

78

CIS 12.5

n. a.

n. a.

Japan 8.0

n. a.

n. a.

China 2.5

n. a.

n. a.

n. a. = not available

Table 2.6. Comparison of pollutant emission rates for different technologies.

Emission for 1 kWh

CO2 (kg)

SO2 (g)

NO2 (g)

Coal (1%S)

0.95

7.5

2.80

Fuel (1%S)

0.80

5.0

1.80

Gas

0.57

—

1.30

Cogeneration coal

0.57

4.4

1.17

Cogeneration fuel

0.46

2.9

0.99

Cogeneration gas

0.34

—

0.70

CO2 is essentially a greenhouse gas. Although sulfur and nitrogen oxides are much more effective greenhouse gases than CO2 at the molecular level, their much smaller concentrations and shorter lifetimes in the atmosphere make them contribute relatively little to the overall greenhouse effect. They are the main cause of acid rains, as well as of atmospheric ozone. The three main different fossil fuels (coal, gas and oil) have different greenhouse gas emission rates, as shown in table 2.6 [28].

Table 2.6 also shows that, whenever possible, the co-utilization of elec­tricity and heat allows significant gains on the emission rates.[4] Aside from CO2, methane also has a strong greenhouse effect, about one third of that of CO2. Apart from leaks in the gas transportation system and releases from coal mining, methane is essentially produced in the agriculture sector and will not be considered further here. The same applies to CFC and other stable and complex gaseous molecules.