To provide a reliable and comprehensive estimate of emissions from all significant sources, a thorough exercise was undertaken to develop a National Emissions Inventory for Pakistan.The inventory is in Microsoft Excel®.Given in the following directory “sasia/baseline/Pakistan/inventry”.An effort was made to make the spreadsheets as self-contained as possible by providing within them all the information required to understand the numerical calculations.

This document provides general explanatory notes on the sources of data, emission factors, and methodology used to develop the inventory.

1.1 General Scheme of the Inventory

Where A_i is the magnitude of activity in sector i and EF_i is the emission factor of the particular pollutant for the sector i.Examples of activity are fuel consumption (mtoe/yr), industrial production (tonnes/yr) or distance traveled by vehicles (km/yr).The typical emission factors corresponding to these activities are tonnes/mtoe, tonnes/tonnes of production and gm/km.The summation sign indicates that the total emissions for a particular pollutant will be the sum over all activities that result in emissions of that pollutant.

This relationship has been used throughout this inventory.

1.2 Pollutants

aOxides of Nitrogen (NO_X)

aSulfur Dioxide (SO₂)

aParticulate Matter (PM), and

aAmmonia (NH₃).

1.3 Sources of Emissions

aCombustion of fossil fuels in industrial, residential, commercial, agricultural, transportation, government and power generation sectors

aCombustion of biofuels in industrial, residential and commercial sectors

aProduction of cement, fertilizer, sulfuric acid, paper and petroleum products

aAnimal husbandry and fertilizer application.

1.4 Sources of Data

1.Pakistan Energy Yearbook.Prepared by the Hydrocarbon Development Institute of Pakistan.

2.Economic Survey. Published annually by the Economic Adviser’s Wing, Finance Division, Government of Pakistan.

3.Pakistan Railways Yearbook.Published by Pakistan Railways.

4.Agricultural Statistics of Pakistan. Published by the Ministry of Food, Agriculture and Livestock, Government of Pakistan.

5.Pakistan Census of Livestock.Published by Agricultural Census Organization.

6.Various publications of the National Transport Research Center.

1.5 Emission Factors

The following are the main sources of emission factors used in this inventory:

aCompilation of Air Pollution Emission Factors (Stationary Sources), AP-42.Research Triangle Park: US Environmental Protection Agency, 1985

aRevised 1996 IPCC Guidelines for National Greenhouse Gas Inventories: Reference Manual, 1996

aLong-Range Energy Alternative Planning System.Boston: Stockholm Environment Institute, 1995

aEnvironmental Manual for Power Development. Darmstadt: Oeko-Institut, 1995.

1.6 Spatial Coverage

1.7 Temporal Coverage

1.8 Uncertainties

aUncertainty in the basic activity data.This could be due to reporting, measurement or data collection errors

aDiffering interpretations of activity data

aVariations in conditions (fuel properties, operating conditions, vehicle characteristics, etc.) for which segregated data is not available

aApplicability of emission factors.Emission factors are ‘averaged’ values based on related assumptions to represent characteristics of a given population of sources.Most of the emission factors are developed in the US and European countries, and are therefore, applicable to these countries, strictly.In many cases, it can be argued that the emission factors are equally applicable to the conditions in Pakistan as well.However, the differences in climatic and operating conditions are likely to introduce uncertainties for which no estimates are available.

aUse of composite emission factors.Composite emission factors are developed on the basis of weighted averaged values to represent characteristics of a given population of sources.The key assumption in developing such composite emission factors is that the population distribution remains unchanged during the period of study.However, a change in the population distribution would introduce uncertainties in the estimated emissions inventory.

aInherent uncertainty in the scientific understanding of the basic processes leading to emissions.

Due to lack of information in the source data, uncertainties are not estimated in the inventory.

1.9 Organization of the Inventory

1.10 Inventory and the Database

2.1 Energy Flow Scheme

Primary fossil fuels produced indigenously include natural gas, oil, and coal.About 35 percent of the electricity is produced by hydropower plants.Nuclear power plants contribute less than 0.5 percent.Locally produced coal is used only at two power plants and in the brick kiln industry.In the Flow Diagram, fuel for power generation is shown to come directly from refineries, gas production companies, and coal production companies.In reality, the route is much more complex.Petroleum products are supplied to power plants by petroleum marketing companies and are also imported directly.Similarly, natural gas is supplied by transmission and distribution companies.However, for the sake of simplicity, these routes are not shown in the diagram.

The last stage of the energy flow, distribution of fuels from the distribution companies to the end-users, is shown through various letters instead of lines.Fuels used for thermal power generation include furnace oil, diesel coal, and natural gas.Small quantities of gasoline, kerosene, and light diesel oil are also consumed in the power generation industry.Exhibit A.1 on the following page summarizes the energy utilization in the industrial, domestic, and transportation sectors.

The database of energy consumption by year is included in the worksheet Table 1.1.A key to the database is provided in the worksheet Energy Diagram Key.The key provides a correspondence between the database and the energy flow diagram.The reference numbers of cells shown in red in the key also appear on the energy flow diagram at the appropriate position in the energy chain.One sector, shown as ‘Other’ in the energy flow diagram and the database, is explained later in Section 2.2.

2.2 Source of Energy Data

The Pakistan Energy Yearbook gives fuel consumption and production data in both metric tonnes and Pakistan tonnes of oil equivalent (toe).The latter unit has been defined by the Ministry of Petroleum and Natural Resources for use in Pakistan and is equal to 41.895 MMBtu (Million British Thermal Units).To avoid any confusion, the abbreviation ‘Ptoe’ is used throughout this document for Pakistan tonne of oil equivalent, whereas ‘toe’ refers to the international tonne of oil equivalent (equal to 41.686 MJ or 39.683 MMBtu).

Since it is a Malé Declaration reporting requirement that the energy consumption database be developed in terms of MMtoe, an intermediate worksheet Table 1.1 (Source Units) has been used for data entry.This worksheet contains data as it appears in the sources, ie, in the units used in the source data table.To minimize errors in data entry, the source data is not manipulated before it is entered in the database.The gray-shaded cells in the worksheet Table 1.1 (Source Units) contain numbers in exactly the same form as they appear in the source data.In cases where it is required that, for example, two numbers from the source be added before making an entry in a cell of the worksheet, the numbers are entered as a formula in the cell.Thus, all manipulation on the source data is done within the worksheet.The beige colored cells contain such formulas.

The methodology for data extraction and the rationale behind it is explained below:

1.The Pakistan Energy Yearbooks reports figures on the fiscal year basis.In Pakistan, the fiscal year starts on July 1st and ends on June 30th of the following calendar year.In this database, the figures shown for a particular year cover the first six months of that year and the last six months of the previous year.Thus, the data shown for 1980 corresponds to the fiscal year 1979-1980.

2.In general, each edition of the Yearbook gives data for the previous 6 years.For example, Pakistan Energy Yearbook, 1999 contains data from 1993-94 to 1998-99.In some cases, the figures for previous years are revised in the later editions.Wherever such changes have taken place, it has been assumed that the figures in the later editions are more accurate and they are used in the database.Thus, for example, the 1993-94 data is taken from the 1999 Yearbook and not the 1994 Yearbook.

3.The Yearbook gives the consumption figures for motor spirit and high octane blending components (HOBC).The consumption figures for Methyle Tertiary Butyle Ether (MTBE) are lumped with motor spirit in the yearbook.The gasoline consumption shown in the database includes, motor spirit, MTBE, and HOBC.Since these fuels have different calorific values, the total energy value of the fuels consumed, expressed in Ptoe, is extracted from the Yearbook rather than the tonnage.

4.Consumption figures for aviation fuels such as JP-1 and JP-4 are not given separately in the Yearbook.Again, for the reasons discussed in the previous point, the total energy value of aviation fuel consumption, expressed in Ptoe, is extracted from the Yearbook and not the tonnage.

5.The Yearbook does not contain the sectoral breakdown of LPG consumption figures.Only the total supply, ie, production and import, is given, which is assumed to be equal to consumption.The sectoral breakdown given in the database is based on the study reported in ENAR, 1992.According to this study, LPG consumption in the residential, commercial, and transportation sectors is 60 percent, 20 percent, and 15 percent of the total consumption, respectively.About 5 percent is consumed in other sectors.

6.Diesel consumption in tractors used in the agriculture sector is included in the transportation sector consumption in the Yearbook.

7.Figures for the energy consumed during crude oil processing are not separately available.It is assumed that this consumption is equal to the difference between the energy value of crude oil supplied to the refineries and the energy value of the products.This difference is expressed as follows:

Where,

E_R =Energy consumed in crude oil processing (in Ptoe)

E_I =Quantity of imported crude oil processed (in Ptoe)

E_L =Quantity of local crude oil processed (in Ptoe)

E_P =Quantity of total petroleum products (in Ptoe)

W_N =Weight of non-energy petroleum products

H_N =Equivalent heat content of non-energy products.IPCC, 1996 recommends a value of 40.19 GJ/tonne (0.90924 Ptoe/tonne).A value of 0.91 Ptoe/tonne has been used in the database.

8.In the above formula, the values for E_R, E_I, E_L, E_P and W_N have been obtained directly from the Yearbook.However, for the first four years (1980, 1985, 1990 and 1991), the quantities of imported and local crude oil processed by the refineries are not given separately in the Yearbook.Only the total weight of crude processed is available.Thus, the total energy value of the processed crude is not known.To calculate this the following procedure is adopted: 

For 1992-1998, 37.5 percent of crude processed in the all refineries was local, whereas, the remaining 62.5 percent was imported.It is assumed that this ratio was the same before 1992.Further, it is known that the energy value of imported crude is 1.0338 times the energy values of the local crude oil (the calorific values of different fuels are discussed later).Thus, the energy value of the crude processed in the refineries (E_R+E_L) was set equal to:

where, W_C is the total weight of the crude processed in the refineries (in metric tonnes).

9.In the Yearbook, industrial consumption of natural gas is given separately for the cement, fertilizer, and ‘general’ industries.The fertilizer industry uses natural gas as both fuel and feedstock.However, separate consumption figures for these are available only after 1997.For years prior to 1997, the Yearbook recommends that feedstock consumption be assumed as 60 percent of the total natural gas consumption in the fertilizer industry.Thus, for years before 1997, the industrial natural gas consumption is the sum of the consumption in the cement and general industries and 40 percent of the fertilizer industry’s consumption, as given in the Yearbook.The feedstock consumption in the fertilizer industry is shown under the column ‘Other.’

10.Natural gas consumption at the gas processing plants has been obtained directly from the ‘Primary Energy Balance Sheet’ of the Pakistan Energy Yearbooks.The number represents the difference in energy value of the gas supplied to the processing plant and that supplied by the processing plant to the transmission companies and consumers.The numbers in the balance sheet are given in Ptoe.The volume of equivalent gas is obtained using the calorific value of 980 Btu/cf.The gas processing plant consumption for 1980 and 1985 is not available.

11.Non-energy oils include lubrication oil, solvent oil, turpentine, asphalt, grease, wax, process oil, and carbon oil.The production data for these oils for 1980, 1985, 1990 and 1991 is not available.

12.The electricity consumption figure is based on the electricity supplied to the consumers by public utilities.Electricity produced by captive power plants is not included.

13.Apart from sectoral electricity consumption, the electricity produced by hydel and nuclear power plants is also shown.The electricity produced by these two sources, after deduction of transmission and distribution losses (approximately 26 percent), is already included in the total electricity consumption figures.The production figure for hydel and nuclear energy is shown under the ‘Other’ column only for convenience of presentation and does not imply consumption in this sector.

14.The last column “Other Uses” includes the following:

cConsumption of petroleum products, including non-energy oils, directly by the government agencies

cBulk supply of electricity, and electricity used for street lighting

cLPG consumed in the fishing and ship-breaking industries

cNatural gas consumed as feedstock in the fertilizer industry.

15.Reliable historical data for biofuel (fuelwood, animal residue, crop residue, and wood charcoal) consumption is not available.A nationwide household energy survey was conducted in 1991 (HESS, 1993).The total consumption of biofuel in the country, as reported by this study, is shown in the 1991 database.The same study also reported that the annual growth rate of biofuel consumption is 2 percent.The biofuel consumption for other years has been estimated in the database using this growth rate.The calculation is shown in the worksheet Biomass.

2.3 Calorific Value of Fuels

aImported coal

aLocal coal

aKerosene

aHigh speed diesel

aLight diesel oil

aFurnace oil

aLPG

aNatural gas.

Three fuels in the databases are mixtures of more than one fuel.These are:

aAviation fuel (JP-1 and JP-4)

aGasoline (motor spirit, HOBC and MTBE)

aCrude oil (local and imported crude oils).

The effective calorific value of these fuels is determined on the basis of weighted average of the last six years of production.These computations and results are provided in the worksheet FuelProperties.

The effective heating value of non-energy oils is taken from IPCC, 1996.

The heating value of biofuels is taken from the HESS, 1993 study.A comparison with heating values from some other sources is also shown in the worksheet FuelProperties.

2.4 Sulfur Content of Fuels

2.4.1 Indigenous Coal

Lakhra Coal Field in Sindh is the sole source of coal for the only major coal-based power plant in the country.[1]The average concentration of sulfur in Lakhra coal has been used to represent the sulfur content of coal in the power sector.

To compute the effective sulfur content of coal used in the other sectors, a weighted average of sulfur content in Pakistan’s coalfields has been calculated on the basis of the last six years’ production.Production from Lakhra used in this calculation does not contain the power plant consumption.The computation is shown in the worksheet Sulfur Content–Coal.

2.4.2 Other Fuels

aAny available measurement has been used

aWhere no measurement is available but specifications for maximum concentration of sulfur are given, the maximum limit is assumed as the prevailing concentration

aIf no information from the above two sources is available, values recommended by various emissions inventory guidelines and typical values from other countries are reviewed and the most likely value, based on similarity of conditions, is selected.Where different values are given by different sources and not enough information is available to ascertain the likely value for Pakistan, a conservative approach is taken and the highest value selected.

A complete list of sulfur contents of fuels from several sources is given in the worksheet Sulfur Content–Coal.The table of selected values for sulfur content of Pakistan’s fuels and the rationale for each selection are also given in this worksheet.

2.5 Sulfur Retention in Ash of Fuels

2.6 Graph of Energy Consumption

1.Fuel-wise consumption of energy

2.Sectoral consumption of energy.

The fuel-wise consumption plot is for end-users only.It does not include energy consumed in power generation and fuel conversion.The energy consumed in power generation is already included as electricity.The energy consumed in fuel conversion is not included because the consumption takes place at the supply side of the energy chain.The way they are computed, the figures also partly include losses in transmission and distribution.Since, this factor is not included anywhere else, the fuel conversion consumption figures are not comparable with the rest of the data.

The sectoral consumption graphs include power generation.However, to avoid double counting, electricity is excluded.

3.1 Emissions Calculation

Where is the total emissions for the pollutant p (NO_X, PM, etc.); is the distance traveled (km/yr) by vehicle type i (car, van, bus, truck, etc.) operating on fuel type f (diesel, gasoline, etc.); andis the emissions (g/km) of the pollutant p for the vehicle i, operating on fuel f.

To apply this equation, the following information is required:

aVehicle population by type and size

aFleet composition by fuel

aFuel consumption for type of vehicle

aAnnual average distance traveled by each type of vehicle

The information was obtained from various reports, in particular, publications of the National Transport Research Centre.

3.2 Energy Reconciliation

The LPG energy consumption is not reconciled since the LPG consumption in the transportation sector is not directly reported (see the fileH0BL1MAL-Energy.xls).

3.3 Specific Emissions

4.1 Type of Sources

aThermal power plants

aDiesel-engine driven pumps for groundwater wells

aLamps, cooking stoves, water and room heaters

aIndustrial furnaces, boilers and engines

The worksheet Uses describes the sources in more details.

4.2 Emission Factors for Power Generation

5.1 Sources

aPaper and pulp production

aOil processing (refineries)

aSulfuric acid production (SO₂ only)

aNitrogen Fertilizer Production (PM only)

aCement Production.

5.2 Composite Emission Factor for Cement

6.1 Emissions of Ammonia

aAnimal husbandry

aFertilizer application

aFertilizer production

aHumans

aFossil fuel combustion.

6.2 Sources of Data

1.Agricultural Statistics of Pakistan, published by the Ministry of Food, Agriculture and Livestock, Government of Pakistan

2.Pakistan Census of Livestock, published by Agricultural Census Organization, Lahore.

Livestock censuses are conducted after every 10 years.The last three censuses took place in 1976, 1986, and 1996.In this inventory, the livestock population is based on these three censuses.For years between the censuses, the growth rate is determined as follows:

Where,

r_1986-1996 is the growth rate for the 10-year period 1986 to 1996;

P₁₉₉₆ is the population in 1996 determined by census; and

P₁₉₈₆ is the population in 1986 determined by census.

This growth is then used to determine the population for the years 1987 to 1995 as follows:

Where,

n is the year for which population estimate is required; and

P_n is the population estimate for the year n.

Commercial poultry data is available for the years 1981-1986 only.Population for other years has been estimated by developing a correlation between the total meat production, as reported in the Agricultural Statistics of Pakistan, and the population of commercial and poultry chickens.

6.3 Emission Factors for Ammonia

A composite emission factor for cattle and buffaloes has been developed.Battye, 1994 proposes different emission factors for cattle, based on sex, age, and activity.The composite emission factor proposed in the report is 22.9 kg NH₃/animal.This value is based on the US cattle population.The composite emission factor developed for Pakistan is 20.82 kg NH₃/animal.The number is lower because the composition of Pakistan’s cattle population differs from that in the US.The composite emission factor for buffaloes, computed on the assumption that the emission factor for cattle is applicable to buffaloes, is 24.19 kg NH₃/animal.

The calculations for these emission factors are shown in the worksheet Cattle&Buffalo_EF.

6.4 Emissions Calculations

This relationship is used for estimating emissions from all sources.The calculations are shown separately in the worksheets Animal_Husbandry, Fertilizer_Application,Fertilizer_Production, Humans, and Combustion.

An emissions inventory for beet sugar production has also been calculated.However, since its value is negligible compared to emissions from other sources, it is not included in the total.The calculations are shown in the worksheet Beet_Sugar.