Economy
& Energy
Year IX -No
52:
October - November
2005
ISSN 1518-2932
No
52 Em
Português|
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Economy
& Energy |
No
52 Em
Português |
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Espirito Santo will turn into Bolivia
Carbon Balance in the Greenhouse Effect Gases Emissions in Energy Use and Transformation in Brazil: Analysis of Results and Conclusions.
Text for Discussion: Alternative to the Additional Protocol of the IAEA Nuclear Safeguards Agreement
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Article: Carbon Balance Concerning the Emissions of Greenhouse Effect in the Energy Use and Transformation in Brazil: Comparison between the Extended Top-Down and Bottom-Up Methodologies – Analysis of Results and Conclusions.Carlos Feu Alvim, Frida Eidelman and Omar Campos Ferreira feu@ecen.com, frida@ecen.com, omarecen@pib.com.br IntroductionThe Economy and Energy Organization has made together with the Ministry of Science and Technology a study about carbon balance in the emissions resulting from the use and transformation of energy. The dissemination of the results of this study has been made by the e&e periodical. The following results have already been published: ● Carbon Balance in the Production, Transformation and Use of Energy in Brazil – Methodology and Results of the Top-Bottom Process in the period 1970 – 2002 (e&e N 48). ● Carbon Balance in the Energy Transformation Centers (e&e N 50). ● Results corresponding to the adopted accounting process that includes the extended Top-Down approach and the use of coefficients calculated in the national inventory for the period 1990-1994 for estimating emissions from 1970 to 2002 by the Bottom-Up process (e&e Nº 51). In the present issue the results of both methods are compared and some deviations found are pointed out; they should bring about corrections in the inventory of carbon balance and emissions inventory. Suggestions regarding the corrections are presented and they will be the object of a complementary analysis. Comparison of Emissions using the two MethodsThe benemis program made for calculating emissions permits to obtain synthetic tables grouping energy sources and economical sectors. In the case of the benemis_c_eee version the contained carbon data, emissions using the two processes and their comparison can be obtained for each year. Table 1 shows the values of contained carbon without discounting emissions of the main consuming sectors and energy sources grouped by origin[1]. In the following tables the emissions calculated by the Top-Down (Table 2) and Bottom-Up (Table 3) methods are compared in the aggregated form. Table 4 illustrates the procedure used for the comparison: the discrepancies relative to these two methods are indicated by colors with limits fixed by percents of deviations (white for differences below 0.1% or zero values, green, between 0.1% and 10%, yellow, between 10% and 30% and red, above that value). Concerning the aggregated tables, there is an additional difficulty namely the aggregation criterion of fuel by origin. In the case of gases, for example, residential gas had different origins along time and in the usual BEN’s structure it is presented together with coke plant gas. In the program’s present representation by origin it is recorded as mineral gas. Table1: Carbon Contained in Fuels Used in Gg/year, Year 1990
Table 2: Carbon Emissions in Gg/year (1990) – Top Down Method
Table 3: Emissions by Sector and by Group of Fuels - Year:1990 - Gg /year Bottom-Up
(*) Excludes Transformation Identifying the problems is easier when one examines the difference by fuel and when the accounts have a larger disaggregated form. This will be carried out in what follows. Preliminarily, it should be observed that in Table 4 the red cells for mineral coal identify problems concerning the fuel by origin, mainly gas. Some deviations pointed out for biomass are due to difficulties already detected in transformation. Figure 1 shows the emissions by sector and by fuel by origin obtained using coefficients obtained in the Bottom-Up process. The Transport Sector is the largest sector responsible for carbon emissions from fossil sources. The following tables illustrate the results obtained from calculating the carbon balance (year 1990) and are used in the analysis of the existing problems. The first two tables (Table 5 and Table 6) show the original carbon content in the fuels used in transformation and consumption. In transformation, the negative masses show (as in BEN) the absorption of an energy source that is transformed into another one and recorded as positive input on the same line. For the transformation centers where emissions are not calculated (Petroleum Refineries, Natural Gas Plants, Gasification Plants, Coke Plants, Distilleries and Other Transformations), the “Total” column on the right points out the faults in the carbon balance. Later on, using the results of the following tables it will be possible to complete the carbon balance of the remaining transformation units.
Table 4:
Comparison of Results of the two Processes.
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