Electric Energy Demand

Economy & Energy
No 23 December 2000 - January 2001
ISSN 1518-2932

No 23 em
Português

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Progress in the Energy Matrix and in the Emissions of Gases Causing the Greenhouse Effect

Main Page
Introduction
Reference Economic Scenario

Preliminary Evaluation for the 2000-2020 period
Demand in Equivalent Energy
Electric Energy Demand
2000 – 2020 Thermoelectric Generation

Participation of Fuels used in Generation
Necessary Thermal Generation Capacity

Emissions in Thermal Power Plants

Conclusions and Sensitivity Evaluation

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2 – Electric Energy Demand

2.1. Participation of Electric Energy in Energy Consumption

The projection of electric energy participation in equivalent energy consumption permits the coupling of electric energy consumption to the considered economic scenario. The adopted procedure is similar to that used for projecting demand in equivalent energy.

In Figure 2.1 it is shown the participation of electric energy in the total for different countries (whenever possible the same as those of Figure 1.2). It can be noticed that electric energy participation, in the same way as it historically occurred in Brazil, increases with the variation of GNP/inhab. In opposition to what was observed in global consumption, Brazil has a relatively important electricity participation when compared to countries with equivalent GNP per capita.

Participation of Electricity in Equivalent Energy
Elect. Part. GNP/inhab.
Figure 2.1: Participation of electric energy in global consumption of energy, measured in equivalent energy. It can be noticed that Brazil presents a relatively important electricity participation in the total. The values refer to 1996 and were obtained with the simplified methodology. The values in purchasing power parity of product per capita of the countries are also indicated, referring to the axis on the right.

In Figure 2.1 we show the evolution of electric energy participation in equivalent energy and its projection. In order to guide the maximum relative consumption option it was considered that the best adjustment for Brazil corresponds to a superior limit of 33% for electricity participation. On the other hand the average of the nine richest countries is 39%. An adjustment for a future limit value of 34% was considered. This value is slightest superior to the best fit and takes into account a recovery indicated in the scenario’s GNP per capita as well as values superior to that of the richest countries. The adjustment and the projection for the considered limit value (34%) can be seen in Figure 2.2.

Electric Energy/Total (in Equivalent Energy)
Electric Energy/equivalent Energy Adjustment Projection
Figure 2.2: Participation of electricity in the total consumption in equivalent energy, historical and projected values.

2.2 Projection of Electric Energy Demand

Figure 2.3 shows projections in values of the GNP, Equivalent Energy and Electric Energy consumption relative to 1998. The growth rate regarding GNP, energy and electric energy use are presented in Table 2.1 for the indicated periods.

Table 2.1 Growth Rates in the Periods

	1995-2000	2000-05	2005-10	2010-15	2015-20
GNP	2.1%	2.1%	3.5%	3.3%	3.6%
Equivalent Energy	3.8%	3.2%	4.1%	3.7%	3.8%
Electric Energy	4.3%	3.8%	4.4%	3.8%	3.9%

GNP, Equivalent Energy and Electric Energy
Millions of toe/year (relative to 1998)
GNP, Projection Equivalent Energy, Projection Electricity, Projection
Figure 2.3 Projections of GNP growth, final consumption, expressed in equivalent energy and electricity consumption

The objective of the present work is to offer a tool for evaluating demand and emissions associated with electric energy production by thermal power plants. Other scenarios can easily be analyzed using the developed methodology.

2.3 Evaluation of the Evolution, Imports and the Participation of Self-producers

In order to transform electricity demand at the consumption level into demand at the internal generation level (accounted for as transformation in BEN) it is necessary to evaluate losses in generation and storage and also estimate imports.

In order to link generation demand at the consumer level with electricity production by the public power plants it is necessary to extrapolate the contribution of the self-producers. In the case of electricity we should remember that variations in stock, normally necessary to even the annual balance of any form of energy, are negligible.

Equalizing offer and demand

Production + Net Imports = Final Consumption + Losses

We also have:

Production in Public Power Plants = Total Production – Production of Self-producers

The participation of self-producers in electricity offer can be obtained in the National Energy Balance dividing by the total transformation (generated electricity) the electricity generated by autonomous producers. In order to have an indication of the participation in gross demand (including losses) one must add the net imports to the denominator.

The participation of self-producers in the total installed capacity is also shown in Figure 2.4.

Participation of Electricity Self-producers Participation in Fulfilling Demand Participation in Installed Capacity
Figure 2.4: Participation of self-producers in internal offer, in fulfilling demand (including that of electricity imports) and in installed generation capacity. From 1985 on when Itaipú started operation, imports became significant.

Figure 2.5 shows extrapolation of participation of self-producers in offer considered as tending to the average of the last 10 years, namely 5%.

Extrapolation of Participation Relative to Demad
Losses, Extrapolations Imports, Extrapolations Self-producers, Extrapolations
Figure 2.5: Extrapolation of losses in transmission and storage concerning the participation of imports and self-producers relative to gross demand (consumption + losses). Gross offer (transformation + imports) must be equal to gross demand.

Figure 2.5 shows as well extrapolation of losses were it is considered a reduction due to the introduction of thermal power plants and a larger efficiency in the production management. It is also shown the extrapolation of imports’ participation that we have supposed, as a first approximation, to have reached 10 % of fulfillment of demand.

In Table 2.2 the values used in the extrapolation are shown. The last known value (1999), the values of projected stability and the time constants used are indicated.

Table 2.2: Values Used in Extrapolation

	Losses	Imports	Self-producers
Projection (% Gross Demand)	14%	8%	7%
Time Constant (years)	8.0	8.0	4.0

One can also evaluate the same parameters as a function of final consumption, as shown in Figure 2.6. Evaluation of demand as a function of the economic activity and of participation in equivalent energy was carried out at the consumer’s level and refers to final consumption, as it is called in BEN, and this makes it interesting to represent the projected values as a function of this consumption.

Historical and Projected Values Relative to Final Consumption
Losses, Extrapolations Imports, Extrapolations Self-producers, Extrapolations
Figure 2.6: Historical and Projected Values relative to final consumption that is the projected value as a function of the economic activity.

Finally, considering electric energy final consumption one can estimate these parameters in absolute value as shown in Figure 2.7.

Historical and Projected Values
Losses, Extrapolations Imports, Extrapolations Self-producers, Extrapolations
Figure 2.7: Historical and Projected Values of losses, imports and participation of self-producers

The objective of the present work is to study alternatives to electricity production and their result on the emission of gases causing the greenhouse effect. In order to do that the developed program presents a summary worksheet in which, starting from the alternatives, the results of participation in electricity generation and in emissions can easily be seen. In the Annex some of these worksheets are shown. In the present case we show the relative and absolute values of losses, imports and the energy generated by self-producers as a function of the adopted parameters for the participation and for the time constants.

In Table 2.3 imports, losses and electric energy production values by self-producers for 1999 and projection for the intermediary years are shown.

Table 2.3: Projection for the reference scenario for electric energy (Twh/year)

	1999	2005	2010	2015	2020
Losses	57	69	75	85	102
Imports	40	45	46	52	63
Self-producers	24	32	38	46	55
Consumption	315	386	474	568	686
Transformation	332	410	504	601	725
Public Service Power Plants	308	378	465	555	670