Relevance and Trends of Industrial Sector Emissions

World's industrial sector emissions of GHGs, which comprise CO2 from energy and from non-energy use of fossil fuels and renewable fuel sources, as well as non-CO2 GHG emissions, amounts 7,200 Mio t CO2-eq. and 12,000 Mio for direct and for total emissions including indirect emissions, respectively. A specification after sources is given in table 10.1.

Table 10.1 Industrial GHG sources and amounts (world's totals) (IPCC, 2007c)

GHG source

Amount Mio t CO2-eq. (reference year)

Specifications

Energy-related CO2

9,900 (2004)

In 1971 the value was 6,000 Mio t CO2-eq., which is equivalent to a 40 percent growth.

Industrial sector's share of global energy use was 37 percent in 2004

Share of developed nations, transition economies and developing nations was 35, 11 and 53 percent, respectively.

CO2 from non-energy use of fossil and nonfossil fuels

1,700 (2000)

Non-CO2

430 (2004)

Includes CH4, N2O, PFCs and HFCs

Not more than 4 percent of world's GHG emissions are directly process related. In the EU industrial production contributes by about 10; in the U.S. by about 5 percent. This is a relatively small position compared to the energy related processes (see figure 9.1). Nevertheless, GHG emission reduction is important also for the industry.

Emissions considered in industry are released as by-products of the reactions which take place in the industrial processes, when raw material is transformed from one state to another in the end product. In addition to that, the industrial processes are also characterized by energy consuming process steps such as heating or cooling for best process conditions, or electrical energy for smelting processes (as in the case of aluminum production), or stirrer power for stirring of the process fluids (as in the case of bioprocesses, liquid-liquid reactions or solvents), and others. Such energy related emissions are considered independent of the process and are not part of the process emission balance.

On the other hand there is a large difference in the GHG potentials of different technologies. Reduction measures are especially important for the industries with largest emissions. A survey of the situation in the USA where industrial processes in 2005 emitted more than 330 Mio t of CO2-eq. is given in table 10.2.

Table 10.2 Total emissions from selected industrial processes in the U.S. industry, 2005, (Mio t CO2-eq.) (EPA, 2007b)

Process

CO2

CH4

N2O

HFCs, PFCs, SF6

All

Substitution of Ozone Depleting Substances

123.3

123.3

Iron and steel production

45.2

1.0

46.2

Cement manufacture

45.9

45.9

Ammonia manufacture and urea application

16.3

16.3

Nitric acid production

15.7

15.7

HCFC-22 production

16.5

16.5

Electrical transmission and distribution

13.2

13.2

Lime manufacture

13.7

13.7

Aluminum production

4.2

3.0

7.2

Limestone and dolomite use

7.4

7.4

Adipic acid production

6.0

6.0

Semiconductor manufacture

4.3

4.3

Petrochemical production

2.9

1.1

4.0

Soda ash manufacture and consumption

4.2

4.2

Magnesium production and processing

2.7

2.7

Titanium dioxide production

1.9

1.9

Among the traditional industrial branches iron and steel production as well as cement manufacture are main emittents. 50 percent reduction happened between 1990 and 2005. A much larger part is emitted by the so called new processes for the replacement of ozone depleting substances (ODSs) by HFCs and PFCs. By 2020, ODS substitutes are expected to account for 60 percent of all industrial emissions. Substantial increases of GHG emissions are projected from HCFC production and electric power systems with growth rates of about 60 and 80 percent, respectively. Semiconductor manufacturing will show almost doubled emissions, despite the adoption of mitigation measures (WWF, 2006). Current emissions and mitigation potentials will be considered in chapter 10.2.

In the majority of all industrial processes CO2 is emitted. Some typical GHGs other than CO2 emitted from selected industrial processes which were displayed already in table 9.2 are given in detail in table 10.3.

Table 10.3 Industrial processes and typical non-CO2-emissions (EPA, 2006)

Product

Emitted GHGs

Adipic and nitric acid

N2O

Substitutes for ozone depleting substances

HFCs, PFCs

HCFC-22

HFCs

Electric power systems

SF6

Primary aluminum

PFCs

Semiconductor

HFCs, PFCs, SF6

Magnesium

SF6

Other miscellaneous industrial products

ch4, N2O

Table 10.4 displays specific emissions of CH4 and N2O and the resulting total specific greenhouse gas potentials for selected industrial processes.

Table 10.4 N2O and CH4 emissions (Schön, 1993) and GHG potentials of selected processes

Product

Emissions (kg per ton of product)

Total GWP (t CO2-eq./t)

N2O

CH4

Ammonia

10.1

0.25

Nitric acid

3.1-6.2

0.92-1.85

Product

Emissions (kg per ton of product)

Total GWP (t CO2-eq./t)

N2O

ch4

Adipic acid

333

99

Methanol

9.1

0.23

Oxo-synthesis products

3

0.07

Acetic acid

9

0.23

Gases other than CO2, CH4 and N2O influence the overall climate effects of industrial processes as well, especially the anthropogenic (man-made) chlorinated and fluorinated hydrocarbons, namely hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs), but also sulphur hexafluoride (SF6). They are summarized under the term High Global Warming Potential Gases (high GWPs). They are used as substitutes for a group of so called ozone depleting substances (ODSs) which have been phased-out in industrialized countries under the Montreal Protocol on Substances that Deplete the Ozone Layer. This usage is growing rapidly. From a current value of nearly 300 Mio t CO2-eq. a rise to about 700 Mio t is envisaged by 2020. But only the substance group is to be characterized as an interim substitute in many applications, for they will also be phased-out under the provisions of the Copenhagen Amendments to the Montreal Protocol.

In some ODSs replacement applications, such as solvent cleaning or aerosol applications, the substitutes are emitted immediately, whereas in others the substitutes are replacing ODSs' in equipment such as refrigerators or air conditioning applications, and are only slowly released.

Moreover, they are employed and emitted by important industrial processes, such as aluminum and HCFC-22 production, semiconductor manufacture, and magnesium metal production and processing. They are also generated through electric power transmission and distribution facilities (see table 10.5).

Table 10.5 High GWPs and their current industrial use (EPA, 2006)

Chemical

Use

Hydrofluorocarbons (HFCs)

Several HFCs

Foam blowing agent and refrigerant, fire suppressant, propellant in metered dosed inhalers and aerosols, plasma etching and semiconductor production

Chemical

Use

Perfluorocarbons (PFCs)

CF4, C2F6

Byproduct of aluminum production, plasma etching and cleaning in semiconductor production and low temperature refrigerants

C3F8

Low-temperature refrigerant and fire suppressant. Used in plasma cleaning in semiconductor production

Sulfur Hexafluoride (SF6)

SF6

Cover gas in magnesium production and casting, dielectric gas and insulator in electric power equipment, fire suppression discharge agent in military systems, atmospheric and subterranean tracer gas, sound insulation, process flow rate measurement, medical applications, and formerly an aerosol propellant. Used for plasma etching in semiconductor production

Hydrofluoroethers (HEFs)

C4F9OCH3

Cleaning solvent and heat transfer fluid

In addition to such greenhouse gases which directly influence climate factors, many industrial processes generate indirect greenhouse gases which occur when chemical transformations involving the chemical substance produce greenhouse gases. Another indirect effect occurs when the gas considered influences other climate relevant processes such as lifetime of atmospheric GHGs.

The most important indirect industrial greenhouse gases are NOx, carbon monoxide (CO) and non-methane volatile organic carbon compounds (NMVOCs). They are produced in chemical and allied product manufacturing, metal processing, during storage and transport, as well as by health services, cooling tower operation, fugitive dusts, various incomplete combustion processes, and accidental or catastrophic releases.

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