Economy & Energy
Year IX -No 58:
October-November 2006   
ISSN 1518-2932

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Evaluation of CO2 Emission between 1970 and 2004 Using the Extended Top-Down Process

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Text for Discussion:

Evaluation of CO2 Emissions Using the Top-Down Extended Process Between 1970 and 2004

Olga Mafra, Frida Eidelman e Carlos Feu Alvim
olga@ecen.com, frida@ecen.com, feu@ecen.com

Summary

1 - Introduction.

2 - Antecedents.

3 - Methodology.

4 -  Use of the ben_eec Programme in the Calculation of Carbon Content

4.1 Calculation of Energy Sources Data Using the ben_eec Programme.

4.2 Cálculation of  Carbon Content in the ben_eec Programme.

5 – Carbon Balance.

5.1 Energy Content per Carbon Content in Fuels.

6 – Cálculation of the Top-Down Emissions.

6.1 – Carbon Retained in Non Energy Use.

6.2 –Non Oxidized Carbon 

7 –References List

List of Tables Available at the Internet

1 - Introduction

This report is part of the data survey for the Carbon Balance revision, object of the Partnership Contract 13.0020.00/2005  between the Economy and Energy – e&e –organization and the Ministry of Science and Technology – MCT.

 It is specifically listed as Goal 1 – “Estimate of C and CO2 Emissions in Energy Use and Transformation from 1970 to 2004 by the Top Down Extended Process”.

The activities foreseen for this phase are: use of carbon balance  in energy production, transformation and use in Brazil in order to evaluate emissions in the period and using the above mentioned approach.

 2 - Perliminaries

The MCT has previously signed the No 01.0065.00-2003 Agreement with the e&e Organization aiming at calculating the carbon balance in the Brazilian Energy Matrix regarding the Brazilian Inventory of the greenhouse effect gases. One of its objectives was to detect eventual incoherence in the initial Inventory by comparing the Top-Down Extended (TDE) and Bottom-Up (using coefficients) processes.

In the first calculation, the Top-Down process was extended so that it would evaluate carbon emissions in the transformation and consumption of energy. The Bottom-Up methodology using coefficients was applied to the emissions  inventory from 1990 to 1994. So, emission coefficients were deduced for the various gases responsible for the greenhouse effect gases by unit of consumed energy and by fuel listed in the Energy Balance.

The result of the previous agreement identified a series of incoherence and omissions that the present Agreement will try to resolve. The objective of the present study is to consolidate a Carbon Balance that can be an instrument to emissions evaluation, helping the establishment of policies for that area.

This Partnership Contract foresees as the first goal the elaboration of the Carbon Balance using the TDE methodology. From the previous study it was concluded that the application of this methodology permitted the calculations of emissions by a process equivalent to the Top-Down by the IPCC methodology using some lines of the Carbon Balance and retention and oxidizing coefficients. This methodology was adopted in Brazil for calculating its inventory and the corresponding results are presented in Reference 1.

Comparison of results has shown a good agreement of data regarding emitted carbon and its CO2 equivalent, around 1.3%. However, concerning analysis by fuel some divergences were detected which is tried to be clarified in the present study.

Furthermore, the present Partnership Contract foresees the improvement and use of computer programs to automate emissions calculations aiming at assisting in the calculation of the next inventories. It is expected that once the incoherence is eliminated in the use of coefficients or conflicting procedures in the two methodologies, some points that need clarification will be defined, including experimental measurements.

This technical note calculates the Top-Down emissions, revises some of the  coefficients and presents the calculation methodology so that future studies can easily incorporate changes in the technical coefficients that are considered convenient.

3 - Methodology

The IPCC (Intergovernmental Panel on Climate Change) Top-Down methodology makes the accounting of the primary and secondary fuel that are introduced in the economic system in order to satisfy the needs of the human activities (even the non-commercial ones) and of how much carbon leaves the system. Once introduced in the national economy, in a determined year, the carbon content of a fossil fuel either is emitted to the atmosphere or is retained in some way, for example, through the increase of fuel stock, its transformation in non-energy products or its partial retention in non-oxidized form in the combustion residues.

The use of the Top-Down (TD) methodology recommended by IPCC in its 1996 revision permits to estimate the CO2 emissions as a function of data regarding the energy supply in the country and a few data concerning their form of use. The data used are from BEN (National Energy Balance) edited by the Ministry of Mines and Energy – MME.

The values supplied by BEN are originally given in natural units that correspond to those used in their origin (mass in tons and volumes in cubic meters). In some cases, where energy sources are grouped, the units used are  ton equivalent petroleum (tep) and a special criterion must be established for calculating emissions.

The Top-Down (TD) methodology calculates the Apparent Consumption of a country by energy source from the equation:

Apparent Consumption = Production + Imports – Exports – International Bunkers + Stock Variation

In practice this concept coincides with data from the Total Internal Supply BEN/MME where:

Total Internal Supply = Production + Imports – Exports (in BEN Bunkers are included) – Non Used – Re-injection

The “Non Used” and “Re-injection” concepts refer specifically to the Natural Gas accounting that, as will be examined below, can be separately treated. However, in order to calculate using the TD process, production excludes re-injection of Natural Gas in the wells and the non-used energy (gas flow to the atmosphere or burned in flares during extraction are not accounted for by TD and are treated separately). This equivalence will be shown below when a practical case will be analyzed.

In a simplified way, the Top-Down methodology can be described as follows:

a)                  Calculation of fuels apparent consumption in their natural measurement units;

b)                  Conversion of the apparent consumption to a common energy unit - terajoules(TJ);

c)                  Transformation of the apparent consumption of each fuel to carbon content by multiplying by the specific emission factor of that fuel;

d)                  Calculation of the carbon amount of each fuel destined to non-energy utilization and subtraction of that amount from the carbon of the apparent consumption in order to calculate the real carbon content that can be emitted;

e)                  Correction of this value in order to consider the incomplete combustion, calculating the true carbon quantity that is actually oxidized in the combustion

f)                    Conversion of the oxidized carbon to CO2  emissions.

             In the adopted methodology, the emissions are calculated by multiplying the values - expressed in energy relative to the final use of the energy sources and some transformation – by coefficients adequate to the fuels used in Brazil or default coefficients recommended  IPCC.

 4 - Use of the ben_eec Program in the Ca;culation of Carbon Content

4.1 calculation of Energy Data Using the ben_eec Program

The BEN / MME (49 sectors and 46 accounts) data base supplies data in natural units from 1970 until 2005. These data are annually published and constitute the National Energy Balance presently elaborated by the Energy Research Enterprise – EPE, for the Ministry of Mines and Energy - MME.

The ben_eec program whose operation manual was presented in the Technical Note 3, annex to the Report No1 of the Partnership Contract E&E/MCT, was previously developed by ECEN Consultoria Ltda for the Economy and Energy Organization e&e. This program was already used in several energy planning studies and it is available at http://ecen.com in the previous version. The present version improves the calculation structure and facilitates the data revision.

Using original data expressed in natural units (mass, volume or, in case of aggregations, in ton equivalent petroleum – tep) and coefficients for each energy source and year, the program converts data to energy units (Mcal) using energy/mass or energy/volume coefficients. Presently, the MME used as base the low heat value (LHV) but previously the values were given in high heat value (HHV). These data are used in the conversion of the usual data from the energy source balance that is the ton equivalent petroleum presently defined as:

1 tep = 10.000 Mcal with the energy content measured in LHV values

Previously, BEN/MME used the relationship:

1 tep (old) = 10.800 Mcal with the energy content measured in HHV values

Furthermore, the adopted equivalence for electricity took into account the quantity of fuel oil necessary for generating electricity. Presently, the conversion is made directly in energy. Thus the following equivalence:

1 kWh=860 kcal=0,086 tep (new)

            Previously, the adopted equivalence was:          

1 kWh was equivalent to 3132 kcal = 0,29 tep (old)

The previous literature (such as reference document concerning the initial inventory of greenhouse effect gases emissions) used old units such energy coefficients relative to HHL and values in tep (old). For this reason, the program supplies to the user results in this unit and in tep (new) and LHV. It should be noted that the LHV and HHV are not equivalent and may have other applications for the user.

The ben_eec program also converts energy to equivalent energy (that takes into account the average relative efficacy of the energy sources in each sector) and in carbon content that is used for calculating emissions and test the coherence based on the conservation of carbon atoms in the  involved chemical reactions in the use of the energy source.

The MME supplies annually the values used in the conversion to tep. This means that the old tep and HHV coefficient values are available until 2002. As these values were subsequently converted to new tep, the new tep and the implicit LHV values are also available for all years. Based on these values of the LHV/HHV ratio for each fuel and extrapolating to the years subsequent to 2002 it is possible to supply data for all the years in the old and new units. For each j fuel and i year, there is a coefficient c(i.j) such that

[Energy in tep] (i,j) = [Quantity in Natural Units] (i,j) × c(i.j)

Furthermore, the r(i,j) = [Energy in new tep](i,j) / [Energy in old tep ](i,j) ratio permits to convert from new tep to old tep and, based on the energy equivalence previously mentioned, it is possible to supply the energy values in Mcal for both the LHV and HHV. This conversions are automatically carried out by the program. Besides that, the ben_eec software permits to construct tables chosen by the user and make several aggregations, including renewable and non-renewable energy that are important regarding emissions accounting.

In Table 4.1 it is illustrated how the program calculates the values in different energy equivalence in the different presentation formats. In this technical not are not shown examples regarding electricity, hydraulic and nuclear energies that are of no interest to the present study since in these cases there is neither carbon content nor emissions directly involved.

Table 4.1:   Illustration of calculation carried out by the ben_eec program in energy and carbon conten

1994   Petroleum Humid Nat.Gas  Dry Nat. Gas  Steam Coal 3100 Steam Coal 3300 Steam Coal 3700 Steam Coal 4200 Steam Coal 4500 Steam Coal 4700 Steam Coal 5200 Steam Coal 5900 Steam Coal 6000 Non Spec. Steam Coal Nat. Met.Coal  Imp. Met.Coal Other Non Ren. Firewood SugarCane Liquor Molasses SugarCane Bagasse Black Liquor Other Rec.  Diesel Oil
Gross Domestic Supply   10^3 m3 10^6 m3 10^6 m3 10^3 t 10^3 t 10^3 t 10^3 t 10^3 t 10^3 t 10^3 t 10^3 t 10^3 t 10^3 t 10^3 t 10^3 t 10^3 tep 10^3 t 10^3 t 10^3 t 10^3 t 10^3 t 10^3 tep 10^3 m3
A Natural Units 70885 0 5265 -112 0 0 319 1696 387 89 1379 272 572 97 240 0 11188 135 0 0 242705 80218 0
B=A*x 10^3 tep 62986 0 4631 -33 0 0 128 721 172 44 772 155 163 62 178 0 3467 8 0 0 69386 80218 0
C=A*y 10^3 old tep 61812 0 4510 -32 0 0 124 706 168 43 753 151 159 61 176 0 3417 8 0 0 68065 74276 0
D=10*B  PCI (Tcal) 629861 0 46313 -330 0 0 1275 7205 1721 436 7719 1550 1630 622 1775 0 34669 81 0 0 693859 802180 0
E=C*10.8  PCS (Tcal) 667567 0 48713 -347 0 0 1339 7629 1818 463 8133 1631 1715 659 1900 0 36906 84 0 0 735102 802180 0
F=D*0.004187*z Gg of Carbon 52742 0 2967 -36 0 0 138 778 186 47 834 167 176 67 192 0 4151 7 0 0 58101 67171 0
  HHV/LHV    1,060 1,053 1,052 1,051 1,065 1,057 1,050 1,059 1,056 1,061 1,054 1,053 1,053 1,059 1,070 1,000 1,065 1,033 1,072 1,060 1,059 1,000 1,052
x Conversion new tep 0,889 0,993 0,880 0,295 0,310 0,350 0,400 0,425 0,445 0,490 0,560 0,570 0,285 0,642 0,740 1,000 0,310 0,060 0,180 0,213 0,286 1,000 0,871
y Conversion old tep 0,872 0,968 0,857 0,287 0,305 0,342 0,389 0,417 0,435 0,481 0,546 0,555 0,278 0,629 0,733 0,926 0,305 0,057 0,179 0,209 0,280 0,926 0,848
z tC/TJ 20,0 15,9 15,3 25,8 25,8 25,8 25,8 25,8 25,8 25,8 25,8 25,8 25,8 25,8 25,8 20,0 28,6 20,0 20,0 24,2 20,0 20,0 20,2
                                                 
1994   Fuel Oil Gasoline Aviat. Gasoline LPG Naphtha Lighting Keros.  Jet Keros. Gas Coke  Gas  RJ Gas  SP Coke Oven Charcoal Anhyd. Alcohol Hydrat. Alcohol Refinery Gas Petroleum Coke Other Oil Products Tars Asphalt Lubricants Solvents Other Non Energ.Oil   
  Oferta Interna Bruta   10^3 m3 10^3 m3 10^3 m3 10^3 m3 10^3 m3 10^3 m3 10^3 m3 10^3 m3 10^6 m3 10^6 m3 10^3 t 10^3 t 10^3 m3 10^3 m3 10^3 m3 10^3 m3 10^3 m3 10^3 m3 10^3 m3 10^3 m3 10^3 m3 10^3 m3  
A Natural Units 98986 5866 70543 0 7637 821 0 0 0 2111 133 -29 3156 3042 0 -4 -314 0 -114 0 0 0  
B=A*x 10^3 tep 96221 4615 54291 0 5829 683 0 0 0 950 92 -19 1685 1550 0 -3 -279 0 -112 0 0 0  
C=A*y 10^3 old tep 93641 4523 53542 0 5683 666 0 0 0 918 90 -18 1639 1515 0 -3 -274 0 -109 0 0 0  
D=10*B  PCI (Tcal) 962207 46146 542914 0 58289 6834 0 0 0 9496 917 -187 16851 15504 0 -35 -2790 0 -1116 0 0 0  
E=C*10.8  PCS (Tcal) 1011320 48845 578255 0 61380 7191 0 0 0 9918 971 -197 17699 16366 0 -35 -2957 0 -1175 0 0 0  
F=D*0.004187*z Gg of Carbon 85003 3652 44325 0 4881 561 0 0 0 724 113 -23 1326 1220 0 -4 -234 0 -103 0 0 0  
  HHV/LHV    1,051 1,058 1,065 1,053 1,053 1,052 1,051 1,047 1,026 1,044 1,058 1,053 1,050 1,056 1,048 1,013 1,060 1,053 1,052 1,059 1,050 1,060  
x Conversion new tep 0,972 0,787 0,770 0,616 0,763 0,832 0,833 0,430 0,380 0,450 0,690 0,646 0,534 0,510 0,655 0,873 0,889 0,855 0,979 0,890 0,793 0,889  
y Conversion old tep 0,946 0,771 0,759 0,601 0,74419 0,811 0,811 0,4165 0,36097 0,43501 0,67566 0,62938 0,51928 0,49813 0,63556 0,819 0,872 0,833 0,954 0,873 0,771 0,872  
z tC/TJ 21,1 18,9 19,5 17,2 20,0 19,6 19,5 29,5 18,2 18,2 29,5 29,9 18,8 18,8 18,2 27,5 20,0 25,8 22,0 20,0 20,0 20,0  

The example refers to a line of the spreadsheet for 1994 (Total Energy Supply). The table shows the original data (natural units indicated in the first line), the conversion factors indicated as new tep (10.000 Mcal) and old tep (10.800 Mcal). In the first column are shown the conversion formula as well as the factors regarding carbon content calculation that will be commented in what follows.

4.2 Calculation of Carbon Content in the ben_eec Program

The carbon content calculation is carried out using coefficients given in tons of contained carbon per contained energy (LHV) for the different energy sources (last line). These coefficients can in principle have different average values for each year. The usual unit of these coefficients is ton of contained carbon per Terajoule, tC/TJ.

In Brazil, considering the inadequate production profile of petroleum products consumption (mainly after the substitution of fuel oil and gasoline after the 1973 and 1979 oil prices crises) and the “dieselization” of the automobile fleet, fuels have rather had a varied utilization. The same happens to fuels of local use such as biomass products intensely used in Brazil. However, the usual practice is to adopt a fixed value (for each fuel) of the carbon mass/ energy coefficient for all years with a few exceptions that will be commented below. It should be noted that the energy / natural unit coefficients variation available for some years in BEN has already some of the fuel variations mentioned above.

Besides the energy in the different equivalences, the program calculates for each column (fuel) the carbon content using the original energy balance data as illustrated in Table 4.1 (year 1994) for the Total Energy Supply account that corresponds, as shown, to Final Consumption in the Top-Down approach. The carbon content value is shown in the last column.

The carbon content is calculated by multiplying the energy content of each fuel (converted to TJ) by the factor shown in the last line. The procedure is valid for all lines (accounts) in the same column.

The conversion factor for calculating the contained carbon mass is based on the conversion of the energy value in Tcal based on the LHV (D in the table) by the 4.1868 TJ/Tcal ratio corresponding to the equivalence of these units. Since the energy content and the contained carbon mass ratio is given by the z factor in Table 4.1, given in Terajoule per ton of carbon, one has:

1 TJ/tC = 4.1868 Tcal/tC = 0. 0041868 Tcal/mil tC = 0.0041868 Tcal/Gg of C

It should be mentioned that it was not possible to use in the present study the LHV adopted by BEN to define ton equivalent petroleum (tep) which was not available in the calculation of the initial inventory (COPPE/MCT reference report). For this reason, when one compares the data from the present study with those of the inventory it should be considered that even though the primary data source is the same, conversions to the LHV are slightly different from those of the HHV.

It is also shown in one of the lines of Table 3.1 the high heat value/low heat value ratio (HHV/LHV) resulting from the coefficients used by the MME. The values are (according to the organizers of the Balance) based on international values. The values oscillate around 1.06. It was expected that they would depend on the hydrogen content of the fuel since the difference between the two types of heat values (see Technical Note No 2) produces water in the combustion process due to the combination of contained hydrogen and the atmospheric oxygen.

 

5 - Carbon Balance

The Application of the described methodology to all lines of the Energy Balance permits the generation of contained carbon spreadsheets for all fuels in all accounts. Since the carbon share that is not released to the atmosphere by the energy use of fossil fuels is very small (around 1%), the Carbon Balance spreadsheets already give a good idea of the emissions by sector or by fuel. They also permit to detect possible errors in the carbon accounting that might influence emissions calculations.

The contained carbon obtained, as shown, is a function of the tep data in the Energy Balance (converted to TJ) and of the emission factor of each fuel (in tC/TJ). In the analysis made in the ambit of the previous agreement with the MCT it was pointed out the inconvenience of using generic coefficients (for liquid and solid biomass) suggested by the IPCC. This subject was object of the Technical Note No 2 that is also part of Report No 1 of the Partnership Contract that originated the present study and was published in the Nº 57 e&e periodical. Some of the emission factors for biomass calculated in the NT 2 were adopted in the present study. In what follows the values adopted in the present study are discussed and they are compared with those used in a previous e&e study, with those used by COPPE and with the consolidation carried out by the MCT team.

 

5.1 Energy Content per Contained Carbon in Fuels

The IPCC supplies emission factors for energy sources (f tC/TJ) for primary and secondary liquid fossils, for primary and secondary solid fossil, natural gas and solid, liquid and gaseous biomass.

 Table 5.1 present carbon emission factors used in the present study and its comparison with other values suggested by IPCC, those used by COPPE (ref), those calculated by MCT and those calculated by e&e. When the emission factor was calculated by e&e this value was used (gray), when not calculated, it was adopted the most repeated values among the options (green) and in case of discrepant values among the different suggestion, the IPCC value was adopted (yellow).

In the same table it is presented the correspondence between the different energy sources as presented by the IPCC and the adopted in the present study.

z = Carbon Emission Factor

From the energy source data in (new) tep converted to TJ one obtains the carbon mass for each of the fuels that are part of the Energy Balance and one can construct the Carbon Balance for each year. The carbon balance in 2004 is presented in Table 5.2 as example.

.

Table: 5.1

 

Used

COPPE

Obtained

MCT

IPCC

 

 

e&e

 

e&e*

 

 

 

 BEN

tC/TJ

tC/TJ

tC/TJ

tC/TJ

tC/TJ

 IPCC

Petroleum

20.0

20.0

 

 

20

Crude Oil

Natural Gas Liquids

17.2

17.2

 

 

17.2

Natural Gas Liquids

Gasoline

18.9

18.9

 

18.9

18.9

Gasoline

Aviation Kerosene

19.5

19.5

 

19.5

19.5

Jet Kerosene

Lighting Kerosene

19.6

19.6

 

19.6

19.6

Other Kerosene

Diesel Oil

20.2

20.2

 

20.2

20.2

Gas/Diesel

Fuel Oil

21.1

21.1

 

21.1

21.1

Residual Fuel Oil

LPG

17.2

17.2

 

17.2

17.2

LPG

Naphtha

20.0

20.0

 

20.0

20.0

Naphtha

Asphalt

22.0

22.0

 

22.0

22.0

Bitumen

Lubricants

20.0

20.0

 

20.0

20.0

Lubricants

Others Non Energ. of Petr.

20.0

20.0

 

20.0

20.0

Other Oil

Petroleum Coke

27.5

27.5

 

27.5

27.5

Petroleum Coke

Steam Coal

25.8

25.8

 

25.8

25.8

Other Bituminous Coal

Metallurgical Coke

25.8

25.8

 

25.8

25.8

Coking Coal

Tar

25.8

25.8

 

25.8

 

Tars

Mineral Coal Coke

29.5

29.5

 

29.5

29.5

Coke Oven / Gas Coke

Natural Gas

15.3

15.3

 

15.3

15.3

Natural Gas (Dry)

Refinery Gas

18.2

18.2

 

18.2

18.2

Other Oil

Other Secondary Sources Petr.

20.0

20.0

 

20.0

20.0

Other Oil

City Gas

18.2

 

 

15.3

 

 

Coke Gas

29.5

 29.5

 

29.5

13.0

Coke Oven Gas

Firewood  Direct Use

28.6*

29.9

28.6

29.9

29.9

Solid Biomass

Firewood for Charcoal Plants

28.6*

29.9

28.6

12.4

29.9

Solid Biomass

Charcoal

29.9

29.9

20.5

32.2

29.9 *

Solid Biomass

Sugarcane Liquor

20.0

20.0

 

 

20.0

Liquid Biomass

Molasses

20.0

20.0

 

 

20.0

Liquid Biomass

Sugarcane Bagasse

24.2*

29.9

24.2

29.9

29.9

Solid Biomass

Residual Vegetal

29.9

29.9

 

29.9

29.9

Solid Biomass

Peat

 

 

 

 

28.9

Peat

Other  Primary Fossils

20.0

20.0

 

20.0

20.0

Other Primary Fuel Fossil

Black Liquor

20.0

20.0

 

20.0

20.0

Liquid Biomass

Anhydrous Alcohol

18.8*

14.8

18.8

14.8

20.0

Liquid Biomass

Hydrated Alcohol

18.8*

14.8

18.8

 

20.0

Liquid Biomass

Tar+ Pyroligneous

 

 

23.9

 

 

 Solid Biomass

 

Key

 

Coincident with IPCC and others

*

Adopted by IPCC

 

Calculated by  e&e

 

(*) The  values recommended by IPCC refer  generically to liquid or solid biomass, those adopted here are those of NT1

6 - Calculation of Top-Down Emissions

6.1 - Carbon Retained in the Non-Energy Use

The carbon retained correspond to the non-energy use. The fuels that have non-energy use are: natural gas, naphtha, illumination kerosene, anhydrous alcohol, hydrated alcohol, refinery gas, asphalt, lubricants, other non-energy petroleum products and tar. In this type of use not always there is carbon retention and the IPCC methodology recommends the use of some coefficients (percent of mass) to take into account emissions that can occur due to natural evaporation (and subsequent conversion to CO2 in the atmosphere) or by burning and degradation of wastes. When they are not supplied, one can use coefficients based on available information. In the present case, the option was to repeat whenever possible the values from the COPPE/MCT report (ref) as follows (Table 6.1):

C = fraction of retained carbon.

Table 6.1 – Fractions of stored carbon

Energy Source

Value

Kerosene

1,0

Naphtah

0,8

Asphalt

1,0

Lubrificants

0,5

 Refinery Gas

1,0

Other non-energy petroleum products

1,0

Tar

0,75

Dry natural gas

0,33

Anhydrous alcohol

1,0

Hydrated alcohol

1,0

 

These values also deserve some comments. For example, hydrated and anhydrous alcohol used in non-energy uses include alcohol used for cleaning (domestic and others) whose end is obviously oxidation in the atmosphere, as already considered in the lubricants case. The same is true for kerosene. Analyzing the subject extrapolates the objectives of the present study. Similarly to these energy sources (used in non-energy ends), other retentions should be considered. For this purpose it was adopted for this coefficient the value 1 for all energy sources (shown in red in the table shown below) so that eventual cases of non-energy uses where part of the carbon is not emitted can be detected

 

6.2 - Non-Oxidized Carbon

In practice the difference between fuel apparent consumption and that retained in non-energy products is the carbon available to be emitted in the combustion. But not all carbon will be oxidized because combustion is not complete and a fraction of non-oxidized carbon will remain in the ashes. The fraction of oxidized carbon (that generates CO2 directly or through the degradation of other compounds in the atmosphere) varies according to the fuel. In the adopted methodology this correction is made through the multiplication by a factor called oxidizing factor suggested by the IPCC.

Table 6.2 illustrates the calculation process, presents the results for 1994 and shows the oxidizing factors values used. In the present study were adopted the oxidizing factors recommended by IPCC. These values were maintained for all years and for most of the energy sources except for two specific cases: natural gas and firewood.

a) Natural Gas

Natural gas contains liquids that must be separated from the consumed natural gas (as such or in the form of dry gas) whose oxidizing is more complete. For liquids of natural gas the 0.99 factor is used (1% is not oxidized) for gases the 0.995 factor is used (5% is not oxidized). The oxidizing factor to be used for the total natural gas will be a weighted average of the share of the two consumption types. At the bottom of Table 6.3 is shown the way to calculate the fraction of liquids and obtain the average oxidizing factor.

The fraction of liquids extracted from natural gas can be obtained by adding the transformation of natural gas in the “Natural Gas Plants”[1] and “Other Transformations”. The emissions obtained by applying the average factor are, as expected, equal to the sum of the values obtained separately for liquids of natural gas and natural gas for direct use (in most cases, dry natural gas).

Table TTable 6.2:  E missions by the Top-Down Process Using the Carbon Balance (Gg/year) shown in Annex 2

 

Emissions by the Top Dow Process Using the Carbon Balance (Gg/ano)

 

Table 6.3  - Equivalence of emissions calculation procedure using factors proportional to the use

 

 GAS NATURAL  

Líquidos de GN

Gas Nat. Uso Direto

Soma Prod GN

 

 LENHA    

Lenha Carvoejamento

Lenha Queima Direta

Soma Lenhas

OFERTA INTERNA BRUTA (A)       

3415

801

2614

3415

 

29756

13125

16631

29756

TOTAL TRANSFORMAÇÃO (B)

-989

 

 

 

 

-13279

 

 

 

PLANTAS DE GÁS NATURAL (C)

-727

 

 

 

 

0

 

 

 

CARVOARIAS (D)

0

 

 

 

 

-13125

 

 

 

OUTRAS TRANSFORMAÇÕES (E)

-73

 

 

 

 

0

 

 

 

CONSUMO NÃO ENERGÉTICO (F)

630

 

630

630

 

0

 

 

 

Coeficientede Retenção (G)

0,33

 

0,33

 

 

 

 

 

 

Coeficiente de Oxidação (H)

0,994

0,990

0,995

 

 

0,879

0,89

0,87

 

Carbono Retido (I=FxG)

208,0

0,0

208,0

208

 

0,0

0,0

0,0

0

Emissões Líquidas de Carb (J=A-I)

3207

801

2406

3207

 

29756

13125

16631

29756

Emissões de Carbono (K=J*H)

3187

793

2394

3187

 

26150

11681

14469

26150

Emissões de CO2 (L=Kx44/12)

11686

2907

8778

11685

 

95884

42832

53052

95884

flgn = Liquids fraction GN = -(C+E)/A = 0,234        flc = Fraction of firewood for charcoal= -D/A=0,441

H=flgn*0,99+(1-flgn)*0,995 =0,994                        H=flc*0,89+(1-flc)*0,87 = 0,879

b) Firewood

For firewood used in charcoal production and firewood for direct use two oxidizing factor are used. The fraction of the former is obtained from firewood transformed in the charcoal units divided by the total supply. The average oxidizing is analogous to the previous case and is also shown in Table 6.3.

The data obtained by using this methodology are compared with those of the COPPE/MCT reference report (Table 6.4). It can be noticed that the changes introduced did not alter substantially the results for the fossil sources (2% in the total) but alter significantly emissions associated with biomass, mainly solid biomass.

Table 6.4  Comparison COPPE/MCT with present Study

Comparison of COPPE/MCT with present Study (continuation Table 6.4)

 

 Comparison of COPPE/MCT with present Study (conclusion  Table 6.4)

 

 

 


            Tabela 5.2:

CARBON BALANCE  - 2004   Contained Carbon  Gg/year

  Primary Energy Petroleum Natual Gas Steam Coal Met. Coal Uranium (U238) Hydraulic En. Firewood Sugar Prod. Other Renew Other Rec. Secondary En. Diesel Oil Fuel Oil Gasoline LPG Naphta Keros. City Gas Coking Gas Uramium W. UO2 Electricity Charcoal Ethyl Alcohol Pet. Oth. Non En. Coal Bitumen O. Sec. Pet. not En. Prod. Non Renewable Renewable Total
Production 144704 64325 11215 2177 148 0 0 33730 28394 0 1400 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 77865 66839 144704
        Imports 35332 19524 4557 0 11252 0 0 0 0 29 0 10585 1932 110 35 897 2882 72 0 1743 0 0 26 3 2478 0 406 45888 29 45917
Stock Variation 135 -78 0 75 137 0 0 0 0 327 0 269 -212 221 -2 65 -184 3 0 53 0 0 0 327 27 0 -28 78 327 405
    Total Supply 180172 83771 15772 2252 11538 0 0 33730 28394 356 1400 10854 1721 331 33 962 2697 75 0 1796 0 0 26 330 2505 0 378 123831 67195 191026
        Exports -10470 -10470 0 0 0 0 0 0 0 -737 0 -12810 -692 -8523 -1235 -58 -11 -912 0 0 0 0 -14 -723 -273 0 -368 -22542 -737 -23280
        Non-Utilized -1103 0 -1103 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 -1103 0 -1103
        Reinjection -2164 0 -2164 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 -2164 0 -2164
    Gross Domestic Supply 166434 73301 12505 2252 11538 0 0 33730 28394 -381 1400 -1955 1029 -8192 -1203 904 2686 -837 0 1796 0 0 12 -394 2232 0 10 98022 66458 164479
    Total Transformation -111726 -73301 -4421 -1912 -7920 0 0 -14874 -7860 10575 -757 91678 26577 13813 11962 4303 3315 2836 0 6662 0 0 5127 5449 6144 230 3593 -6451 -13598 -20049
        Petroleum Refineries -74095 -73301 0 0 0 0 0 0 0 0 -794 74080 28116 14328 11220 3589 5625 2855 0 0 0 0 0 0 4915 0 3431 779 -794 -16
        Natural Gas Plants -1002 0 -1665 0 0 0 0 0 0 0 663 872 0 0 134 604 134 0 0 0 0 0 0 0 0 0 0 -793 663 -130
        Gasification Plants 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
        Coking Plants -7920 0 0 0 -7920 0 0 0 0 0 0 8763 0 0 0 0 0 0 0 6662 0 0 0 0 0 259 0 844 0 844
Nuclear Fuel Cycle 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
        Publ. Util Power Plants -3810 0 -1937 -1862 0 0 0 0 0 0 -11 -1669 -1417 -252 0 0 0 0 0 0 0 0 0 0 0 0 0 -5468 -11 -5479
        Self Prod Power Plants -3743 0 -699 -50 0 0 0 -141 -1425 0 -745 -878 -136 -263 0 0 0 0 0 0 0 0 0 0 -276 -29 0 -1627 -2994 -4621
        Charcoal Plants -14733 0 0 0 0 0 0 -14733 0 5127 0 5127 0 0 0 0 0 0 0 0 0 0 5127 0 0 0 0 0 -9606 -9606
Distilleries -6435 0 0 0 0 0 0 0 -6435 5449 0 5449 0 0 0 0 0 0 0 0 0 0 0 5449 0 0 0 0 -987 -987
Other Transformations 12 0 -119 0 0 0 0 0 0 0 131 -66 14 0 608 110 -2445 -19 0 0 0 0 0 0 1504 0 162 -185 131 -54
        Losses In Distrib/Storage -290 0 -212 -6 -72 0 0 0 0 -203 0 -295 0 0 0 0 0 0 0 -39 0 0 -140 -63 -41 0 0 -382 -203 -585
Final Consumption 54385 0 7838 334 3546 0 0 18856 20534 9990 644 89497 27611 5680 10793 5171 6001 2000 0 8416 0 0 4999 4992 8334 242 3603 91226 52656 143882
        Final Non-Energy Consumption 472 0 472 0 0 0 0 0 0 332 0 10293 0 0 0 0 6001 58 0 0 0 0 0 332 111 188 3603 10433 332 10765
    Final Energy Consumption 53913 0 7366 334 3546 0 0 18856 20534 9658 644 79204 27611 5680 10793 5171 0 1942 0 8416 0 0 4999 4659 8224 54 0 80793 52324 133117
        Energy Sector 9480 0 1923 0 0 0 0 0 7557 0 0 4012 125 918 0 33 0 0 0 0 0 0 0 0 2560 0 0 5935 7557 13492
        Residential 9781 0 116 0 0 0 0 9665 0 396 0 4603 0 0 0 4196 0 11 0 0 0 0 396 0 0 0 0 4323 10061 14383
        Commercial 223 0 138 0 0 0 0 85 0 52 0 468 87 125 0 204 0 0 0 0 0 0 52 0 0 0 0 554 137 691
        Public 30 0 30 0 0 0 0 0 0 0 0 483 105 47 0 331 0 0 0 0 0 0 0 0 0 0 0 514 0 514
        Agriculture 2550 0 1 0 0 0 0 2549 0 5 0 4112 4030 63 0 15 0 0 0 0 0 0 5 0 0 0 0 4108 2554 6662
    Transportation - Total 890 0 890 0 0 0 0 0 0 4659 0 40660 22667 618 10793 0 0 1922 0 0 0 0 0 4659 0 0 0 36891 4659 41551
        Highways 890 0 890 0 0 0 0 0 0 4659 0 37345 21930 0 10755 0 0 0 0 0 0 0 0 4659 0 0 0 33576 4659 38235
        Railroads 0 0 0 0 0 0 0 0 0 0 0 471 471 0 0 0 0 0 0 0 0 0 0 0 0 0 0 471 0 471
        Airways 0 0 0 0 0 0 0 0 0 0 0 1960 0 0 38 0 0 1922 0 0 0 0 0 0 0 0 0 1960 0 1960
        Waterways 0 0 0 0 0 0 0 0 0 0 0 884 266 618 0 0 0 0 0 0 0 0 0 0 0 0 0 884 0 884
    Industrial-Total 30958 0 4267 334 3546 0 0 6557 12977 4546 644 24867 597 3909 0 392 0 9 0 8416 0 0 4546 0 5664 54 0 28468 27356 55824
        Cement 226 0 13 11 30 0 0 0 0 224 172 2222 26 19 0 0 0 0 0 0 0 0 224 0 1952 0 0 2053 396 2448
        Pig-Iron and Steel 3251 0 600 4 2647 0 0 0 0 3857 0 13870 34 69 0 40 0 1 0 8117 0 0 3857 0 418 54 0 13264 3857 17121
        Ferro-Alloys 108 0 1 0 0 0 0 108 0 439 0 731 0 36 0 0 0 0 0 131 0 0 439 0 125 0 0 293 547 840
        Mining/Pelletization 797 0 147 0 650 0 0 0 0 0 0 944 182 468 0 21 0 2 0 0 0 0 0 0 271 0 0 1741 0 1741
        Non-Ferrous 413 0 290 0 123 0 0 0 0 6 0 1778 0 1004 0 27 0 1 0 169 0 0 6 0 572 0 0 2184 6 2190
        Chemistry 1533 0 1321 40 39 0 0 58 0 13 74 2534 126 568 0 14 0 1 0 0 0 0 13 0 1812 0 0 3921 145 4067
        Foods and Beverages 15435 0 314 52 0 0 0 2121 12947 0 0 703 62 535 0 51 0 0 0 0 0 0 0 0 54 0 0 1069 15069 16138
        Textiles 303 0 191 0 0 0 0 112 0 0 0 109 1 101 0 7 0 0 0 0 0 0 0 0 0 0 0 300 112 412
        Paper and Pulp 4787 0 294 96 0 0 0 1363 30 0 372 630 49 561 0 20 0 0 0 0 0 0 0 0 0 0 0 1020 4397 5417
        Ceramics 2502 0 491 56 0 0 0 1929 0 0 26 422 6 261 0 96 0 0 0 0 0 0 0 0 58 0 0 969 1955 2924
        Other Industries 1603 0 606 76 56 0 0 866 0 8 0 923 109 286 0 115 0 5 0 0 0 0 8 0 401 0 0 1654 873 2527
        Non-Identified Consuption 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
        Adjustments -33 0 -33 0 0 0 0 0 0 0 0 71 5 58 34