CO2 emission estimates

Total CO2 emissions

Carbon dioxide emissions in 1999 have reduced by 22% since 1970, as shown in Figure 2.2. However, this decline has not been steady, and peaks were observed in 1973 and 1979 which were due to the state of the economy, high oil prices and severe winters in these years. Emissions fell again during the early eighties reflecting the recession during this period and the coal miners strike of 1984. Since the mid-1980s the emissions profile has been much smoother showing an overall reduction in emissions. There are small increases in several sectors. The elevated emission from the domestic sector in 1996 is considered to be due to the colder than average winter (indicated by lower than average mean air temperatures).

The major emissions of carbon dioxide arise from the combustion of fossil fuels in power generation, and the transport, domestic and industrial sectors (Figure 2.2, Table 2.2). The level of emissions depends on the fuel mix and the fuel consumption data. Details of UK fuel consumption are given annually in the Department of Trade and Industry's Digest of United Kingdom Energy Statistics (DTI, 1999, 2000). The fuel consumption data used to calculate the pollutant emission totals in the NAEI are given in Table 2.3; fuels which are used as feedstocks are omitted (principally natural gas used for the production of ammonia, methanol and acetic acid and some use of LPG and OPG in petrochemical plants).

Table 2.2 UK Emissions of CO2 as Carbon by UN/ECE1 Source Category and Fuel (Mt)

1970

1980

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

1999%

BY UN/ECE CATEGORY2

Comb. in Energy Prod.

Public Power

57.0

58.3

54.1

53.3

50.4

45.5

44.4

44.1

43.5

39.6

40.6

38.5

27%

Petroleum Refining Plants

5.6

5.5

4.8

5.0

5.1

5.4

5.2

5.4

5.6

5.5

5.5

5.0

3%

Other Comb. & Trans.

8.2

2.9

3.8

3.8

3.8

3.8

4.4

4.8

5.2

5.3

5.8

5.9

4%

Comb. in Comm/Inst/Res

Residential Plant

26.5

23.2

21.5

23.9

23.1

24.2

22.9

21.7

24.7

22.7

23.2

23.2

16%

Comm/Pub/Agri Comb.

12.3

9.9

8.4

9.2

9.0

8.8

8.7

8.8

9.3

8.6

8.5

8.3

6%

Combustion in Industry

Iron & Steel Comb.

15.8

5.2

6.2

6.2

6.1

6.1

6.5

6.5

6.6

6.7

6.4

6.2

4%

Other Ind. Comb.

32.3

24.8

18.3

18.5

18.2

17.8

17.9

17.3

17.5

17.4

17.0

16.8

12%

Production Processes

4.9

4.0

4.1

3.3

3.2

3.3

3.5

3.5

3.7

3.6

3.4

3.7

3%

Extr./Distrib. of Fossil Fuels

0.1

0.1

0.4

0.2

0.2

0.1

0.2

0.2

0.2

0.2

0.2

0.2

0%

Road Transport

16.3

21.2

29.7

29.5

29.9

30.3

30.4

30.1

31.3

31.7

31.5

31.2

22%

Other Trans/Mach

Off-Road Sources

2.3

2.0

1.7

1.8

1.8

1.8

1.7

1.7

1.7

1.7

1.7

1.6

1%

Other3

3.3

3.3

3.6

3.3

3.3

3.3

3.1

3.1

3.2

3.0

2.9

2.8

2%

Waste

0.2

3.4

2.2

2.0

2.0

2.0

2.5

1.9

2.0

1.6

1.5

1.4

1%

Land Use Change

0.5

0.4

0.4

0.5

0.5

0.3

0.3

0.4

0.4

0.4

0.3

0.2

0%

By FUEL TYPE

Solid

90.3

70.6

61.4

61.1

57.4

49.4

46.0

42.7

39.5

34.3

34.2

30.3

21%

Petroleum

67.9

54.7

53.2

53.1

53.3

53.3

52.1

50.6

51.9

49.7

48.5

46.7

32%

Gas

22.7

32.2

38.8

41.0

40.7

45.0

47.8

50.7

57.8

58.7

60.5

63.2

44%

Non-Fuel

4.5

6.8

6.1

5.3

5.2

4.9

5.9

5.5

5.6

5.4

5.3

5.0

3%

TOTAL

185.3

164.3

159.5

160.6

156.6

152.6

151.8

149.6

154.8

148.0

148.5

145.1

100%

1 UK emissions reported in IPCC format (Salway, 2001) differ slightly due to the different source categories used.

2 See Appendix 4 for definition of UN/ECE Categories

3 Railways, civil aircraft, shipping, naval vessels and military aircraft.

Figure 2.2 Time Series of CO2 Emissions

Figure 2.3, Spatially Disaggregated UK Emissions of CO2

 

Electricity supply industry

The electricity supply industry is the major consumer of fossil fuels, and hence the major source of carbon dioxide emissions in the UK (Tables 2.2 and 2.3). There have been significant changes in the generating mix between 1980 and 1999, as shown in Figure 2.4. The level of CO2 emissions is determined by both the fuel mix and the generating technology used. During the 1970s the electricity supply industry was dominated by coal and fuel oil fired thermal power stations, and coal and oil consumption increased to meet the rising demand for electricity. The use of coal for power generation peaked in 1980 at 89.6 Mt and has subsequently declined. The fall has not been steady, showing minima in 1982 and 1984 due to recession in the early 1980s and the miners strike of 1984. During the late 1980s and early 1990s, the closure of inefficient plant led to an overall increase in the thermal efficiency of the conventional thermal power plants, and the contribution of nuclear power generation increased with the greater utilisation of existing nuclear plants and the commissioning of Sizewell B in 1995. The use of oil generation peaked in 1972 and apart from increased consumption during the miners strike of 1984 has been in decline ever since. Two oil-fired stations were converted to burn Orimulsion® (an emulsion of bitumen and water) although this practice has been discontinued, largely on environmental grounds. More recently, the privatisation of the power industry has resulted in a move away from coal and oil generation towards combined cycle gas turbines (CCGT). The use of gas in power generation has increased by a factor of 47 since 1991. Further increases may be expected as and when more CCGT stations come on line.

Table 2.3 UK Fuel Consumption

Fuel

Consumer

1970

1980

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

Coal

Major Power Prod.

Mtonnes

77

90

83

82

77

64

61

58

53

45

47

39

Coal

Industry

Mtonnes

22

9

8

8

8

7

7

6

5

5

4

4

Coal

Domestic

Mtonnes

20

9

4

5

4

5

4

3

3

3

2

3

Coal

Others

Mtonnes

38

16

14

13

11

11

11

10

10

10

10

10

Other Solid Fuels

All Consumers

Mtonnes

27

11

11

11

10

10

10

10

10

10

10

10

Motor Spirit

Road Transport

Mtonnes

14

19

24

24

24

24

23

22

22

22

22

22

Gas Oil

Road Transport

Mtonnes

5

6

11

11

11

12

13

13

14

15

15

15

Gas Oil

Industry

Mtonnes

5

5

3

3

3

3

3

3

3

3

3

3

Gas Oil

Others

Mtonnes

8

8

7

7

7

7

7

6

7

6

7

6

Fuel Oil

Major Power Prod.

Mtonnes

12

6

6

6

4

3

2

2

2

1

1

1

Fuel Oil

Refineries

Mtonnes

4

4

2

2

2

2

3

2

2

2

2

2

Fuel Oil

Industry

Mtonnes

21

10

4

5

5

5

4

3

3

2

2

1

Fuel Oil

Others

Mtonnes

15

6

4

4

4

4

4

4

4

4

4

3

Orimulsion

Major Power Prod.

Mtonnes

0

0

0

0

1

1

1

1

1

0

0

0

Burning Oil

Domestic

Mtonnes

2

2

2

2

2

2

2

2

3

3

3

2

Burning Oil

Others

Mtonnes

4

0

0

1

1

1

1

1

1

1

1

1

Aviation Turbine Fuel

Air Transport

Mtonnes

2

1

7

7

7

8

8

8

9

9

10

11

Other Pet. Products

All Consumers

Mtonnes

1

1

1

1

2

2

2

2

2

2

2

2

Petroleum Gases

Refineries

Mtherms

1011

987

1303

1271

1256

1337

1290

1382

1460

1378

1301

1252

Petroleum Gases

Others

Mtherms

700

717

680

780

719

751

891

858

858

760

742

688

Natural Gas

Major Power Prod.

Mtherms

60

55

3

7

396

2488

3606

4540

6029

7633

8087

9599

Natural Gas

Industry

Mtherms

710

6616

7016

6850

6575

6765

7566

7967

8783

9152

9584

10096

Natural Gas

Domestic

Mtherms

627

8420

10250

11395

11264

11607

11250

11124

12824

11790

12144

12150

Natural Gas

Others

Mtherms

2206

2188

3021

3568

3599

3589

3646

3945

4375

4172

4360

4494

Other Gases

All Consumers

Mtherms

7009

1126

1371

1317

1246

1224

1251

1268

1339

1394

1397

1417

 

Figure 2.4 Generating Mix (1980-1999) Million Tonnes Oil Equivalent (Mtoe).

The effect of these changes in the power sector are clearly reflected in the carbon dioxide emissions. Since 1970 electricity generation has increased by 45% but emissions have decreased by around 32%. More significantly, emissions have fallen by 29% between 1990 and 1999. This is due specifically to:

The overall effect of the fuel and technology changes are also clearly illustrated in Figure 2.5 which shows that the average CO2 emission (from power generation) per kWh electricity generated decreases from 245 tonnes/GWh in 1970 to 114 tonnes/GWh in 1999. This trend is likely to continue into the future through the use of more advanced technology and abatement equipment. However, the extent to which nuclear power is used in the future is expected to have a large impact on air emissions. A decreased use of nuclear power for electricity production is expected to give rise to increased consumption of fossil fuels.

Figure 2.5 Average CO2 Emission per unit of Electricity Generated (ktonne/GWh)

Domestic

The domestic use of coal (including anthracite) shows an overall decline between 1970 and 1999, falling by 87%; domestic use of smokeless solid fuels (including coke) has also fallen significantly. This reflects a trend away from solid fuels towards alternatives such as electricity and gas in the domestic sector. Over the same period the domestic use of natural gas has increased by a factor of over 19.

Industrial

The 1999 industrial emissions show a decrease of 45% since 1970. The curve exhibits peaks in 1973, 1979, and 1988 which are due in part to the cold winters in these years but mainly to the various levels of economic activity. According to DTI (2001), industrial energy consumption in 1999 has declined since 1970 by 43% reflecting the decline in a number of the energy intensive industries conducted in the UK and improvements in energy efficiency. Over this period, there has also been a marked move away from coal and oil consumption to gas and to a lesser extent electricity.

Transport

Total emissions from the transport sector have steadily increased since 1970. Of these, road transport emissions have risen by 92% and currently account for 88% of the total transport/mobile machinery emissions in 1999. This also equates to 22% of the total UK carbon dioxide emissions. Emissions fell a little during 1974-75 reflecting the increase in motor fuel prices after the oil crisis. The steady increase in fuel use by most forms of transport reflects the increased demand for transport in the UK between 1970 and 1999. The increased use of private motor vehicles has resulted in a 51% increase in the consumption of petrol from 1970 to 1999. However, petrol consumption has declined by 11% since 1990, which is a result of the increase in popularity of diesel cars, and the increased fuel efficiency of petrol driven cars. Increased use of goods vehicles is reflected in the increase in DERV consumption by a factor of 3 since 1970.

Agriculture/forests/land use change

The effect of changing land-use can result in either net emission or net absorption of CO2 , particularly on a global scale. For example, forest clearing for agricultural use could be a net source of CO2. Recently the Intergovernmental Panel on Climate Change agreed new guidelines for preparing national inventories (IPCC, 1997). Land use change and forestry estimates are included in the UK Greenhouse Gas Inventory (Salway et al, 2001) for the years 1990-99. The estimates have yet to be included in the NAEI which covers the longer period 1970-1999. For comparative purposes the land use change estimates of carbon emissions and removals are summarised in Table 2.4 (Milne, 2000). The new guidelines for Land Use Change and Forestry include emissions from liming of soils under ‘D CO2 Emissions and Removals from Soils’. These are already included in the NAEI under Agricultural Soils.

Table 2.4 Emissions and Removals of CO21 from Land Use Change and Forestry in 1999 (kt)

Sources

Emissions

Removals

A. Changes in Forest and Other Woody Biomass Stocks 1

-

10439

B. Forest and Grassland conversion

-

-

C. Abandonment of Managed Lands

-

-

D. CO2 Emissions and Removals from Soil 2

12663

-

E. Other 3

3608

1100

Total

16271

11539

1 Removals include removals to forest and soil litter, and to forest products.

2 Emissions include removals to soil due to set aside of arable land

3 Emissions include emissions from soil due to upland drainage, lowland drainage and peat extraction. Removals are increases in crop biomass.