e&e No 25
Application of the Emission Matrix Coefficients
In the previous issue we have described the process developed to evaluate emissions by coupling data from the Energy Balance (using final energy values) with general emission coefficients.
As a starting point we have adopted the default coefficients used by the IPCC. A program using the annual tables from BEN/MME (annexes), where final consumption is expressed by fuel and by sector, and coefficients with the same classification was developed. The results found are only indicative since the coefficients are not always adequate to the Brazilian reality.
Application to the past
The objective of this work is to obtain emissions causing the greenhouse effect from data of a projected Energy Matrix. The aim is to evaluate the effect of available alternatives on the emissions We will apply the coefficients to data available from the National Energy Balance – BEN, published by the Ministry of Mines and Energy – MME.
This work has not the pretension to substitute, in the past, the efforts made in the country to satisfy the Brazilian commitments by using the emission inventory. In fact, it would be useful to adapt the coefficients to the values obtained in the calculations. In the specific cases of emissions from vehicles, thermoelectric power plants and charcoal, e&e intends to do that. .As a consistency test of the results obtained in other studies it seems really useful to apply the coefficients of the attached tables. In order to do that we have associated the BENAMEX Program, that presents in a dynamic way data from BEN from 1970 to 1999, to the emission tables and graphics in an automatic way. The same instrument will be used in the future for the emission projections.
We present in what follows some of the results directly obtained by the program.
Table of Annual Emissions by final use
In the present phase we are evaluating emissions starting from the final use and we are not including those relative to the transformation phase. However, we should remember that the final use of the Energy Sector accounts for emissions relative to the use of energy in the transformation. Fundamentally, we have additionally to calculate emissions from electricity production and non-accounted for loses in the final energy. Using the tools that have been developed it is possible to evaluate the annual emissions by sector and by energy source or to evaluate emissions along the years by sector or by energy source.
The results concerning 1999 (CO2) are presented in the annex in Table A6. It should be noticed that the emission coefficients are those of 1999 and specially in the case of transport there is a considerable evolution in the emission factors found.
Table 1 presents the results grouped for the same year and emitted gas.
Table 1: CO2 Emissions in 1999 in Final Energy Use
The graphic in Figure 1 represents the values of Table 2. In Tables 2 and 5 are indicated the emissions of CH4, NO2, NOx and CO in a aggregate form. As previously mentioned, it was considered the carbon balance in each case. The CO2 emissions were corrected considering the carbon content in the CH4 and CO emissions.
Figure 1: Emissions by Sector and by energy source. The CO2 values resulting from biomass have no cumulative effect. The eventual use of non-restored deforesting must be accounted for separately and not accounted for in the final energy as an energy source.
Table 4: NOx Emissions in 1999 in Final Energy Use
Figure 2: NOx Emissions by sector and by fuel aggregated by origin
Figure 3: CO Emissions in 1999 using the coefficients. Absolute prominence of the transport sector can be observed..These values do not incorporate the technological progress introduced in the last years. .
Table 5: CO Emissions in 1999 in Final Energy Use
It is also interesting to present for the chosen year the contributions by sector and by energy source in the aggregation adopted by BEN. These values are shown for CO, year 1999, in Figure 3 in Gg/year. The corresponding final consumption is shown in Figure 4.
Figure 4: Final energy consumption by sector in 1999 (data from BEN/MME)
Emissions by Energy Source in the1970-1999 Period
Considering the emission factor as fixed, the emissions can be calculated along the years or cumulatively. The tool that has been developed permits to obtain these values automatically.
In Figure 5 we show the evolution of fuel oil final consumption and in Figures 6 and 7 the corresponding CO2 and CO emissions. We can observe that CO2 emissions follow the fuel consumption, provided no carbon balance corrections are made. As to CO emissions, they are strongly influenced by the type of use (larger in the navigation sector where the use of motors is predominant)
Figure 5: Fuel oil consumption by sector. It can be observed the decrease of consumption from 19790 on. And a slow resumption from 1983 on.
The graphics of the following figures, aggregated by large sectors of the economy, show the evolution of CH4, N2O, NOx, CO and CO2 (including biomass) and CO2 (excluding biomass) in the 1970 to 1999 period. The coefficients shown in the annexed tables, constant along time, were used.
Figure 8: CH4 Emissions in final energy in the 1970-1999 period
Figure 9: N2O Emissions by sector. It can be observed a strong increase of the emissions (of small total mass) with the introduction of alternative fuels after the petroleum price crisis in 1973 and 1979.
Figure 10: NOx Emissions along the 1970/1999 period for all the final energy in the energy sector.
Figure 11: CO Emissions along the 1970/1999 period
Figures 12 and 13: Comparison between CO2 emissions in the period including and excluding biomass (according to IPCC recommendation)
Emissions by Sector in the 1970-1999 Period
The emissions can also be evaluated along the years as well as cumulatively in chosen periods. In Figure 14 the evolution of CO2 emissions in transport is shown. The emission concerning alcohol should not be accounted for since it comes from the production of planted biomass.
Figure 14: Emissions in the transport sector by fuel. The emissions due to alcohol use should not be computed for greenhouse effect evaluation purposes.
It is also interesting to verify the evolution of the Industrial Sector in the period, as shown in Figure 14 and the participation of the sectors in the emissions corresponding to the total Energy Consumption.
Figure 15: CO2 Emissions in the Brazilian Industry by energy source in the 1970/1999 period.
Figure 16: CO2 Emissions in the final energy consumption in Brazil in the 1970/1999 period. It should be emphasized the strong participation of biomass in the CO2 emissions which are not accounted for in the final use.
The association of BEN/MME data concerning final energy consumption with emission coefficients can give a first approximation of greenhouse effect gases emissions connected with energy consumption. By improving the annual coefficients data one can get a good approximation of the emissions. These results together with assumptions about the behavior of these factors is an interesting instrument to evaluate future emissions.