Progress in the Energy Matrix and in the Emissions of Gases Causing the Greenhouse Effect
Evaluation for the 2000-2020 period
3.1. Reference Expansion Plan
The electric expansion plan is under revision. The Government has recently published an expansion plan for the thermal capacity to be installed. Since our aim is to create instruments for analyzing different scenarios we prefer to refer to the 1999/2008 Expansion Decennial Plan, where a schedule for introduction of different power plants and not only of thermal plants is given. The distribution among the different types of power plants will be taken as reference for the basic hypothesis.
The historical generation capacity and that foreseen in the Plan are shown in Figure 3.1
Figure 3.1: Historical and Projected Generation Capacity for Brazil in the 1999/2008
Expansion Decennial Plan
A expansão das térmicas por tipo de combustível, projetada no Plano, é mostrada na Figura 3.2.
Addition to the Installed Thermal Capacity (from December 1998 on)
NG, VC, Nuclear, Thermal Total
It can be noticed that a large participation of natural gas in the installed capacity is foreseen. The participation of nuclear energy in 2008 was projected assuming the operation of Angra II (effected in 2000) and Angra III which, as other projected power plants, will have some delay in its implementation.
For the 1999 and 2000 years we have the following comparison between the Decennial Plan and what was actually achieved.
Sources BEN 2000(*) and ANEEL Summary Table (http://www.aneel.gov.br) (**)
Figure 3.3: The participation of conventional thermal plants has had some delay but they will have a more important participation in the future.
Participation of Conventional Power Plants in the Addition to the Installed Capacity
Decennial Plan, Historical, Approved by ANEEL, Scenario of the Present Work.
In Figure 3.3 the participation of thermal power plants compared with that established by the 1999/2008 Decennial Plan is shown. In the same graphic we show the results of the extrapolation of participation in the reference scenario. We describe in what follows how the indicated values were obtained.
3.2. Evolution of the Capacity Factor and of the Required Installed Capacity
The evolution of the utilization factor considered in the Decennial Plan cannot be directly obtained from the published data. It is possible to calculate the capacity factor for the years 2003 and 2008 from the total demand and from the installed capacity. It is assumed that the global load factor would vary linearly between 1998 and 2003 and between the latter and 2008 and that it would remain constant in the following years.
Figure 3.3 shows the evolution of the capacity factor obtained from the ratio between the generated energy and that that would be obtained using the nominal capacity along the year. Extrapolated values regarding the Decennial Plan and the hypothesis of the present work are also indicated.
The natural gas power plants should be used in the system’s base until alternatives to them should arise. The capacity factor of the thermal power plants should be increased. In the present work we are assuming a superior limit of 0.55 (55%) of the theoretical capacity utilization as well as some thermal power plants acting as regulators of annual cycle variations.
Figure 3.4: Graphic of the Evolution of the Electric Power Plants’ Capacity Factor. Extrapolated values based on the Decennial Plan until 2008 and on BEN’s data are also shown. The values adopted by the present work for thermal plants and global values are also shown.
Hydraulic, Thermal, Our Projection, Nuclear, Total, Projection of the Decennial Plan.
The capacity factor concerning the use of the total installed generation capacity is not explicitly quoted in the Decennial Plan. However we can infer that it would be 0.501 in 2003 and 0.494 in 2008. These values refer to BEN’s installed capacity, which are slightly different from those used by Eletrobrás. On the other hand we have used the losses values assumed in our work since we have not found explicit references to losses adopted by the Decennial Plan.
The average of the capacity factors according to BEN’s data is 0.539 between 1975 and 1999. In the following years a better performance of the nuclear power plants and a larger use of thermal power plants, due to the reasons mentioned above, are expected.
Even though there are reasons to hope for a lower risk rate for the system we prefer to consider a global utilization factor in the future slightly lower than the historical average tending to 0.53.From the projection of electricity demand (relative to 1998) and from the capacity factor one can obtain the evolution of the installed capacity supposing that losses follow the behavior previously described.
Figure 3.5 shows the evolution of the installed capacity for the
reference economic scenario compared with that of the Decennial Plan. The
two capacity factors until 2008 were considered just for comparison.
Historical and Projected Installed Capacity
Historical, Reference Scenario with Decennial’s Capacity Factor, Decennial Plan
Energy demand is strongly dependent on the economic scenario and on the admitted hypothesis for the capacity factor. The comparison made in Figure 3.5 makes it possible to separate the influence of both factors. In order to define generation demand in each one of the power plant types it is necessary to have the values of the capacity factors to be adopted when planning each type of power plant. Figure 3.6 presents the historical evolution and that resulting from the hypothesis considered for the evolution of the capacity factor of thermal power plants and for the total.
Projected Thermal Generation Capacity
Historical, Decennial Plan, Scenario of the present work
In Figure 3.3 above we can compare the values of addition to the thermal capacity of thermal generation foreseen in the Decennial Plan with both the capacity approved by ANEEL and that resulting from the present work’s hypothesis.