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ELECTRICITY

DEMAND

STEAM

Figure 1 Energy Conversion Steps from Primary Energy to End-Users where:

EI = Energy intensity, national level FC = Total final consumption, national level GDP = Gross domestic product

The Standard Industrial Classification (SIC) groups industrial establishments according to their primary economic activity. Each major industrial group is assigned a two-digit SIC code. The SIC system, which serves as a framework for the collection of energy consumption and output data, divides manufacturing into 20 major industry groups and non-manufacturing into 12 major industry groups. The intensity of energy end-use in industry varies according to requirements specific to the type of industries such as manufacturing, agriculture, forestry, fishing, construction and mining operations. Six of the major 20 industry groups in the manufacturing sector account for more than 80 % of energy consumption:

(1) Food and kindred products,

(2) Paper and allied products,

(3) Chemical and allied products,

(4) Petroleum and coal products,

(5) Stone, clay, and glass products,

(6) Primary metals.

Table 1 summarizes the key characteristics of energy-using industries with an overview of each. For industry or a production process, the energy intensity is called specific energy consumption and it is expressed as a ratio between units of product and corresponding amount of energy consumed.

where:

SEC = Specific energy consumption E = Energy consumed to produce NPO NPO = Units of product

Table 2 shows specific energy consumptions for different industries. These data are sector aggregated and therefore can be used only for the rough benchmarking of energy consumption among different industries from the same sector.

Energy use relative to manufacturing output has been falling more or less continuously in most developed countries since the 1970s. This is caused by a structural shift away from energy intensive products, and also by improvements in energy efficiency and changes in individual energy intensities within each manufacturing subsector. There are various databases on energy consumption that contain the data necessary to undertake comparisons of energy use in industry. For instance, the ODYSSEE database provides comprehensive data on energy consumption by end-use sectors, as well as energy efficiency and CO2 related indicators. The ODYSSEE indicators are macro-indicators, defined at the level of the economy as a whole, the level of a sector, and the level of an end-user. Seven types of indicators are considered in order to monitor energy efficiency trends or to compare energy performances:

• energy intensities relating energy consumption to macro-economic variable;

• unit consumption or specific consumption relating energy consumption to physical indicator of activity;

• 'bottom-up' energy efficiency index to provide the synthesis of energy efficiency trends assessed at disaggregated level;

• adjusted indicators to make cross-country comparisons that attempt, as far as possible, to adjust structural differences between countries (climatic, economic or technical);

• diffusion indicators for monitoring the diffusion of energy efficient equipment and practices;

• target indicators to set up for each country a target or benchmark in comparison to countries with better performances;

• CO2 indicators complement energy efficiency indicators.

The Energy Information Administration of the USA Department of Energy (DOE) and the International Energy Agency (IEA) also maintain very comprehensive databases on industrial energy consumption.

Table 1 General Characteristics of Industrial Energy Consumption. Reproduced from: Energy Information Administration, Office of Energy Markets and End Use, Manufacturing Consumption of Energy 1991, DOE/EIA-O512(91)

SIC*

Major Industry Group

Description

s

20

Food and kindred products

This group converts raw materials into finished goods primarily by chemical (notphysical) means. Heat is essential for their production, and steam provides much of the heat. Natural gas, fuel oil, by-product and waste fuels are the largest sources of energy in this group. All, except food and kindred products are the most energy-intensive industries.

r e

26

Paper and allied products

onsu Co

28

Chemicals and allied products

r e n

29

Petroleum and coal products

H i

32

Stone, slay and glass products

S

33

Primary metal industries

s

34

Fabricated metal products

This group produces high value-added transportation vehicles industrial machinery, electrical equipment, instruments, and miscellaneous equipment. The primary end-users are motor- driven physical conversion of materials (cutting, forming, and assembly) and heat treating, drying, and bonding. Natural gas is the principal energy source.

ers s ons

35

Industrial machinery and equipment

Co d e d d s

36

Electronic and other electric equipment

37

Transportation equipment

s

38

Instruments and related products

39

Miscellaneous manufacturing industries

21

Tobacco manufacturers

This group is the low energy-consuming sector and represents a combination of end-use requirements. Electric motor drives are one of the key end-users.

22

Textile mill products

ers s ons

23

Apparel and other textile products

)

24

Furniture and fixtures

H

25

Lumber and wood

§ iJ

27

Printing and publishing

30

Rubber and miscellaneous plastics

31

Leather and leather products

* SIC - Standard Industrial Code

Source: Energy Information Administration, Office of Energy Markets and End Use, Manufacturing Consumption of Energy 1991, DOE/EIA-0512(91).

Table 2 Specific Energy Consumption in Industry1. Reproduced from: ODYSSEE Energy Efficiency indicators in Europe database

INDUSTRY

End-user consumption

Primary energy1

Thermal

Electricity2

Thermal to total

Total

toe/t

MWh/t

toe/t

%

toe/t

Brewing

G.G5G

G.1G

G.GGS6

85 %

0.0720

Brick

G.G?5

G.G5

G.GG43

95 %

0.0860

Cement

G.GSG

G.ll

G.GG95

89 %

0.1043

Chocolate

G.2GG

2.GG

G.172G

54 %

0.6409

Dairy

G.15G

G.5G

G.G43G

78 %

0.2602

Engineering

G.3GG

2.?5

G.2365

56 %

0.9063

Flour products (pasta, etc.)

G.G4G

G.16

G.G13S

74 %

0.0753

Foundry

G.3GG

G.9G

G.G??4

79 %

0.4984

Ham, sausage

G.1GG

G.35

G.G3G1

77 %

0.1772

Hot pressing

G.25G

G.?5

G.G645

79 %

0.4153

Ice cream and cake

G.1GG

G.?5

G.G645

61 %

0.2653

Milk processing

G.G2G

G.1G

G.GGS6

7G %

0.0420

Non-ferrous metal

G.G?G

G.3G

G.G25S

73 %

0.1361

Paper and pulp

G.15G

G.43

G.G3?G

SG %

0.2448

Plastic

G.G5G

G.55

G.G4?3

51 %

0.1713

Rubber

G.1GG

5.GG

G.4299

19%

1.2023

Textile (dyeing)

G.?5G

G.?5

G.G645

92 %

0.9153

Textile (spinning)

G.45G

?.5G

G.6449

41 %

2.1035

Wood

G.G2G

G.G6

G.GG52

79 %

1 Electrical energy consumption is multiplied by 1/0.37 to get primary energy for its generation. This assumes an average efficiency of electricity generation of approximately 37 %. 21 toe = 11.63 MWh.

3 Environmental Impacts of Industrial Operations

The biggest environmental impacts in industry come from the use of fossil fuels (oil and coal). The fossil fuels are converted into useful energy through a combustion process. The combustion process results in significant impact on the natural environment and generate emissions into the air, water and soil (Table 3). The main emissions into the air from the combustion of fossil fuels are SO2, NOx, particulate matters, heavy metals, and greenhouse gasses such as CO2.

Table 3 Environmental Impacts by Source, Type and Substances

SOURCE RELEASE

SUBSTANCES

AIR (A) WATER (W) LAND (L)

Particulate Matter

Oxides of Sulfur

Oxides of Nitrogen

Oxides of Carbon

Organic Compounds

Acids, Alkalis, Salts, etc.

Hydrogen Chloride/Fluoride

Volatile Organic Compounds

Metals and their Salts

Chlorine (as Hypochlorite)

Mercury and/or Cadmium

PAHs

Dioxins

Fuel Storage and Handling

W

A

Water Treatment

W

W

W

Exhaust Gas

A

A

A

A

A

A

A

A

A

A

Exhaust Gas Treatment

W

W

W,L

W

Site Drainage Including Rainwater

W

W

Waste Water Treatment

W

W

W

Cooling Water Blow-down

W

W

W

W

W

Cooling Tower Exhaust

A

Table 4 Sources of Emissions Released by Combustion Plants Related to Total Emissions. Reproduced from: EMEP/CORINAIR Emission Inventory Guidebook - 2006, http://reports.eea.europa.eu/EMEPCORINAIR4/ en/page002.html

Source Category

Contribution to total emissions, [%]

SO2

NOx

NMVOC

CH4

CO

CO2

N2O

nh3

Combustion plants over 300 MW, including:

Public power plants District heating plants Industrial combustion plants

85.6

81.4

1G.2

5.5

16.8

79.G

35.7

2.4

Combustion plants from 50-300 MW, including:

Public power plants District heating plants Commercial and institutional boilers Industrial combustion plants

6.4

5.4

1.1

G.6

3.1

6.5

1.9

G.2

Combustion plants below 50 MW, including:

Public power plants District heating plants Commercial and institutional boilers

Industrial combustion plants

G.2

G.3

G.1

G.G5

G.1

G.2

G.G1

G (N1)

Gas turbines used in:

Public power plants District heating plants Commercial and institutional installations Industry

G

G.39

G.G7

G.G6

G.G5

G.35

G.G2

n.a.

Stationary engines used in:

Public power plants District heating plants Commercial and institutional installations Industry

G.G4

G.1G

G.G4

G (N1)

G.G1

G.G2

G (N1)

N1 Emissions are reported, but the precise number is below rounding limit n.a. Data not available

An example of the contributions of the main sources of emissions released by combustion plants related to total emissions is given in Table 4.

Even if fuels are not converted into final energy in an industrial plant itself, the electricity and heat that the plant uses have to be produced elsewhere, therefore the plant is responsible for indirect environmental impacts, the extent of which will depend on the power plant technologies and fuel sources used to generate it in aparticular country. In Europe, a simplified approach has been introduced to derive emission factors in order to account for the environmental effects of electricity and heat. It is called the 'European Electricity and Heat Mix', and it provides multiplication factors for calculating the impact of the use of electricity by a business. To create 1 GJ (277.8 kWh) of electrical energy, the average primary energy of fossil fuels is 2.57 GJ (efficiency of electricity generation is 38.9 %). This production assumes consumption of 9.01 kg

Table 5 Resources Used and Emissions Caused by Use 1000 kWh of Electricity, http://www.epa.gov/tri/

Resource Used

Emissions

Oil (kg)

32.43

Gas (m3)

24.91

Coal (kg)

G.47

Brown Coal (kg)

124.69

SO2 (kg)

G.36

CO2 (kg)

42G.12

NO2 (kg)

G.58

of fuel oil, 6.92 nm3 of natural gas, 0.13 kg of coal and 34.64 kg of brown coal. The emissions for such electricity generation are 0.1 kg SO2, 116.71 kg CO2 and 0.16 NO2. For example, the use of 1000kWh of electricity will create environmental impacts as shown in Table 5.

Apart from environmental impacts arising from energy use and conversion of fossil fuels, the processing of raw materials through a string of manufacturing operations is another source of major impacts on the natural environment. Most countries nowadays have national legislation in place that sets the limits for allowed emission values from various pollution sources, and prescribes procedures for emissions monitoring and compliance assessment. The types of impact are as diverse as the types of raw materials used and technologies applied for their processing. Particularly hazardous substances are always covered by legislation and environmental permits. Some examples will be provided latter in the text (see 7.1).

4 End Use Energy Efficiency

Energy efficiency can be defined in various ways (Box 2) but essentially, it always refers to a ratio between useful energy or final energy services and input energy.

Box 2: Definition of Energy Efficiency

To define the energy efficiency of an installation or a system, it is necessary to determine system boundaries and to define precisely all mass and energy flows that pass through the boundary. Then 'input' energy, 'useful' energy or system output and 'losses' need to be defined. The table below gives examples of steam turbine, heat exchanger, boiler and refrigeration systems where system boundaries are determined, input energy and useful energy are identified, and energy efficiency is defined in different ways.

To define the energy efficiency of an installation or a system, it is necessary to determine system boundaries and to define precisely all mass and energy flows that pass through the boundary. Then 'input' energy, 'useful' energy or system output and 'losses' need to be defined. The table below gives examples of steam turbine, heat exchanger, boiler and refrigeration systems where system boundaries are determined, input energy and useful energy are identified, and energy efficiency is defined in different ways.

Schematic

Energy Efficiency Definition

Boundary

Isentropic Efficiency:

Steam Turbine

Where:

H = m-r = Enthalpy, kJ m = Mass flow rate, kg/s r = Specific enthalpy, kJ/kg r^t = Enthalpy of steam after isentropic expansion from point 1 to the

©

OUT

pressure equal to real process.

Box 2: Continued

Flue Gases

System W boundary \5s

sai

Air

©

CD

i

Whcrc:

Wmin = Less of mhot ■ Cp,hot and mcoid ■ Cp,cold, kJ/K m = Mass flow rate, kg/s cp = Isobaric specif ic heat, kJ/(kgK)

Boiler efficiency:

Qf m4 h4-m3 h3

MfGCV

Where:

GCV = gross calorific value, kJ/kg m = flow rate of steam or water, kg/s h = steam or feed water enthalpy, kJ/kg

I EE

Coefficient of Performance:

Qeva = Heat flow rate entering the evaporator, kJ/s EE] = Electrical power, kW

Condenser

Electrical Motor

Electrical Motor

I EE

Improving energy efficiency, i.e. obtaining more final energy services from less energy - is the surest and most direct way of increasing sustainability of the use of energy resources and decreasing the negative aspects - environmental pollution and financial costs - associated with using energy and producing goods. The economic potential of even more efficient energy use will continue to grow with new technologies and with cost reduction resulting from the economy of scale.

Energy efficiency is beneficial to everyone. It lengthens the time for which fossil fuels will be available to meet the world's growing energy needs, for consumers - energy efficiency saves money, and for everyone - improved energy efficiency reduces environmental hazards and greenhouse gas emissions.

5 Efficiency of Using Raw Materials

Closely related to, and of equal importance to energy efficiency is the efficiency of using raw materials, their waste minimization and recycling. Changes in energy and material use efficiency are driven by higher energy and raw material prices, technical improvements, energy conservation and waste minimization programs that are promoted by energy and environmental policies.

A considerable proportion of manufacturing costs is directly related to the raw materials necessary for production. The use of raw materials is both an input element, in terms of the amount of raw materials needed for production and an output element, in terms of the amount of raw materials that is ultimately wasted. Materials accounting or, in other words, measurement and tracking materials' usage within a process, helps improving the efficiency of raw materials usage. Materials balance calculations can be used to verify measurements/estimates of waste quantities, based on the amount of input materials and product yield.

More favored option

PREVENTION

'minimization*

REUSE

RECYCLING

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