In Section 2 we examined the gross dynamics of the global energy system over the past 100 years. There we focused on the competition between different primary energy sources for shares of the world's energy market. The details of the human choices, the technological advances, and the economic shifts and forces that are buried within the macroscopic regularities were not ad- dressed explicitly.
In Section 3 we explored the technical limits of different primary energy sources over the next half century and beyond.
The focus was on resource potentials and engineering possibilities.
Again the details of energy demand patterns were afforded less attention, and the competition between different sources - the central consideration of Section 2 -was not dealt with explicitly.
This section explores in detail future energy demand and the competition among different energy sources contributing to meet- ing this demand. We extend the analysis only as far as 2030.
The quantitative results are expressed in two reference sce- narios and three supplementary cases that are variations of the ref- erence scenarios. The principal tool used in building the scenarios and alternative cases was the set of computer models outlined briefly on page 37.
The two scenarios are labeled the "high scenario" and the "low scenario." The former assumes relatively higher economic growth rates throughout the world, and the latter assumes relatively lower worldwide economic growth. The high scenario leads to a level of global primary energy consumption in 2030 equal to 35.7 TWyr/yr, which amounts to slightly more than four times the 1975 level of
8.2 TWyr/yr, while the low scenario yields a global primary energy consumption in 2030 of 22.4 TWyr/yr, a little less than three times the 1975 level. (See the Appendix for energy unit conversion factors and for definitions of the levels of energy use.)
The two scenarios are not meant to describe extremes in either direction, but rather to cover a middle ground. Neither are they in- tended as predictions; instead, the objective was to detail the engi- neering and economic consequences that follow from two different sets of reasonable assumptions. Nonetheless the results of the exer- cise suggest powerful trends within our current global energy sys- tem, and it is worth listing these before describing the scenarios.
In the developed regions of the world there is a tremen- dous potential for energy conservation from efficiency improve- ments and expanding the economic sectors that are less energy intensive, such as the service sector. For these regions the average growth rate for final energy from 1975 to 2030 is only 1.7% per year in the high scenario and 1.1% per year in the low scenario.
These values compare to a 1950-1975 average of 3.8% per year.
In the developing regions expanding populations, increas- ing urbanization, and continuing development needs limit the pros- pects for energy savings. As a result, throughout the 1975-2030 period primary energy growth rates in these regions are predomi- nantly higher than the gross domestic product (GDP) growth rates, although the differences tend to decrease with time. In contrast, in the developed regions the primary energy growth rates are always below the GDP growth rates.
The production and consumption of oil in both scenarios go up, not down, compared with 1975. Although oil's share of the primary energy market decreases from 1975 to 2030 (from 47% to 19% in the high scenario and from 47% to 22% in the low scenario), the absolute amounts of oil used go up (from 3.83 TWyr/yr in 1 975 to 6.83 TWyr/yr in 2030 in the high scenario and from 3.83 TWyr/yr in 1975 to 5.02 TWyrlyr in 2030 in the low scenario).
Despite such increases, and even with vigorous conserva- tion measures in the industrialized regions, increasing needs for liquid fuels throughout the world may, over the next five decades, exceed the capabilities of the global energy supply system. In the high scenario primary liquid fuel demand increases from 3.83 TWyr/yr in 1975 to 11 . l TWyr/yr in 2030. In the low scenario the increase is from 3.83 TWyr/yr in 1975 to 7.22 TWyr/yr in 2030.
These 2030 demand levels exceed 2030 oil production levels by 63%
and 44% for the high and low scenarios, respectively.
The gap between liquids demand and oil supply is closed by liquefying tremendous quantities of coal. For the high scenario, 6.7 TWyr/yr of coal are liquefied in 2030; for the low scenario the figure is 3.4 TWyr/yr. For both cases this amounts to liquefying more than half the coal mined in 2030. For orientation, the high- scenario value of 6.7 TWyr/yr of coal is equivalent to 4.3 TWyr/yr of crude oil, which nearly equals the total world crude oil produc- tion of 1978.
What oil is produced will come increasingly from uncon- ventional sources - tar sands, oil shales, heavy crudes, and enhanced recovery techniques. In the high scenario the shift is such that by 2030 the majority of the oil produced is, in fact, unconventional oil.
Population growth. The assumptions about population growth were presented in their aggregate form in Figure 2; Table 5 disag-
TABLE 5 Global population projections (in millions of people) by region.
Projection
gregates them by region. We see that 90% of the projected popu- lation growth between 1975 and 2030 occurs in the developing Regions IV (LA), V (AfISEA), VI (MEINAf), and VII (CICPA).
The population assumptions for both scenarios are identical.
Economic growth. Figure 8 shows the average 1975-2030 gross domestic product (GDP) growth rates assumed for each of the seven different regions for the two scenarios. These averages, how- ever, mask an important characteristic of both scenarios - that in all regions of the world, the rate of economic growth continually decreases. The more detailed data are given in Table 6 along with historic growth rates for the periods 1950- 1960 and 1960- 1975.
Except for the case of Region I1 (SU/EE) in comparison with Region VII (CICPA), the growth rates in the developing regions consistently exceed those in the developed regions, although never by much.
That the gap is not larger reflects a recognition that, for the next several decades at least, the developing countries will still be tied t o the economies of the rest of the world through trade and other institutional relations.
Unlike the population assumptions presented earlier, the eco- nomic growth rates of Table 6 do not represent initial assumptions that remained unchanged throughout the subsequent analysis. They are rather the result of several revisions designed t o ensure their consistency with the evolution of energy demand and supply that is calculated t o follow from them.
Technological progress and structural changes within econo- mies. For these two categories, which include the sorts of technical and social changes usually labeled conservation, it is more difficult to summarize all the scenario assumptions in a few graphs or tables.
As an indication of the extent to which energy conservation assump- tions are reflected in the two scenarios, Figures 9 and 10 therefore present some of the aggregate results of the scenarios.
Figure 11 is a schematic representation of the IIASA set of energy models as they were used in constructing the scenarios.
The analysis began with assumptions belonging to each of the four categories just mentioned: population growth, economic growth, technological progress, and structural changes within econ- omies. An Energy Demand Model then calculated for each of the seven regions the resultant evolution of final energy demand from
1980 t o 2030.
The projected final energy demands were translated into pro-
TABLE 6 Historical and projected growth rates of GDP for the IlASA high and low scenarios (percentlyear). Historical Scenario projection 1950- 1960- 1975-1 985 1985-2000 2000-201 5 201 5-2030 Region 1960 1975 High I Low High ( Low High I Low High 1 Low I (NA) 3.3 II (SUIEE) 10.4 Ill (WEIJANZ) 5 .O IV (LA) 5 .O V (AfISEA) 3.9 Vl (MEINAf) 7 .O Vl l (CICPA) 8 .O World
Historical
r\
Regior
'F
Projected
Region I I
Year
Figure 9. Final energy per unit of gross domestic product for the high scenario in (a) developed, and (b) developing regions.
Projected
-
- Region I
Projected .
375 1985 2000 201 5 2030 Year
Figure 10. Final energy per unit of gross domestic product for the low sce- nario in (a) developed, and (b) developing regions.
Projected Historical
C
(U Region VI
C
ii 0.0 1 I I I I
3 153ta 1985 2000 2015 2030
Scenario Definition
r--- 4
ieconomic, popu-)
lation growth) I
Economic Structure, Lifestyles, Technical Efficiencies
I
I
I I I IImpact Mode
Product~on L i m ~ t s
for each world region
Interregional Energy Trade
ormal mathematical models
(-7
Assumptions, judgments, manual calculations A Direct flow o f information (only major flows shown)--- -b Feedback flow of information (only major flows shown)
Figure 11. A simplified representation of the IlASA set of energy models used in constructing the scenarios.
jected secondary energy demands, which were then input to an Energy Supply and Conversion Model. Other inputs t o this model were, first, assumptions constraining energy supply and conversion possibilities (see Figure 1 1) and, second, the results of a procedure analyzing the patterns and prices of oil imports and exports among the seven regions.
The Energy Supply and Conversion Model calculated the pri- mary fuel supplies and conversion facilities needed t o meet the pro- jected secondary energy demands at lowest cost and within the
specified constraints.
Associated with providing the resources and facilities indicated by the Energy Supply and Conversion Model, there are necessarily direct and indirect requirements for capital, materials, manpower, equipment, land, water, and additional energy. In particular, capaci- ties within crucial mining and manufacturing industries have t o be expanded. These related industrial capacities, as well as the direct and indirect requirements listed above, were calculated for each scenario using a model labeled simply Impact.
This short summary is necessarily slightly misleading in that it presents the models linearly and suggests that the analysis simply began with the input for the first model, used each in turn, and ended up with some final results from the last model. In reality, as is usually the case with such sets of models, they were used in paral- lel and iteratively. The objective was internal consistency within each scenario, which in turn required several iterations of the mod- el set. The major consistency checks between models are suggested by the dotted lines in Figure 1 1.
The resultant final energy consumption per capita in each region of the world is shown in Table 7 for both the high and low scenarios. Table 8 shows the corresponding primary energy require- ments. Whether expressed in terms of final energy consumption or primary energy requirements, the results of both scenarios indicate a noticeable reduction in the gap between the energy budgets of the developed regions .and those of the developing regions. The reduction is greater in the high scenario, where, because of overall higher economic growth rates, the developing regions are able t o catch up more than they do in the low scenario. Still, in both sce- narios, the advances achieved in 2000 and 2030 by the developing countries lie well below their currently expressed aspirations. For example, even in the high scenario, the 2030 per capita final energy consumption in Region IV (LA) remains below the 1975 level in Region I1 (SU/EE). And Region V (Af/SEA) has by 2030 only just passed where Region IV (LA) was in 1975.
As shown in Table 9, energy consumption growth rates de- crease throughout the scenarios for all regions, though once again there is a noticeable difference between developed and developing
TABLE 7 Per capita final energy consumption (kWyr/yr) calculated from
TABLE 8 Primary energy requirements by region (TWyrIyr) calculated from the scenarios.
Includes 0.21 TWyrIyr of bunkers -fuel used i n international shipments of fuel.
regions. Part of the difference is due t o the lower economic growth rates assumed for the developed regions, but part of it is simply because regions that use more energy today have more opportunities t o conserve.
The resultant contributions of each primary energy source toward meeting the projected demand levels are shown in Table 10.
For both scenarios the level of use increases for each source of pri- mary energy. Most importantly, this includes the fossil sources - coal, gas, and especially oil. For, although the share of primary
TABLE 9 Final energy growth rates for 1950-1975 and projections to 2030 (percentlyear) calculated from the scenarios.
High scenario Low scenario
TABLE 10 Global primary energy by source (TWyrIyr) for the high and low scenarios.
'"other" includes biogas, geothermal, and commerical wood use.
b~olumns may not sum to totals because of rounding.
energy requirements that is met by oil decreases in both scenarios (Figure 12), the absolute amount of oil used increases.
However, the oil used in 2030 is very different from that used today. Figure 13 shows how the scenarios project that the future primary liquids demand of the regions with noncentrally planned economies will be met. Except for oil from Region VI (MEINAf), none of the oil used after 20 10 comes from currently known re- serves of conventional oil. And by 2030 the portion of the primary
Hydro Renewable
00f-Y'-
-
I
- 1-
1_ i .
.
i , CoalL
Figure 12. The global primary energy shares by source for (a) the high scs- nario, (b) the low scenario.
- Gas
liquids demand that is met by conventional oil reserves, including those yet t o be discovered, is small. For the world as a whole, Figure 14 describes essentially the same story, though using slightly differ- ent terms.
Even with the projected increases in oil production of all sorts, Figures 1 3 and 14 indicate that in the 2 1 st century the scenarios project an increasing gap between the demand for liquid fuels and the supply of oil. The gap is filled by liquefying coal at a rapidly increasing rate, as shown in Figure 15.
Two questions are immediately raised by these results. Why do the fossil fuels continue t o dominate the world's energy system so persistently? And, given this fact, how much fossil fuel is left in 2030, according to the scenarios?
T o the first question, two partial answers can be offered:
First, there is the steadily increasing demand for liquid fuels, although both scenarios assume that in the future they will increasingly be reserved for essential needs (such as transportation and chemical feedstocks). In a sense, the demand for liquid fuels constitutes the key problem within the energy problem.
Second, the rates at which new technologies can replace older, more inefficient users of fossil fuels are limited (see Section 2). Figure 15, for example, indicates that even by 2030 coal used for generating electricity is far from having been replaced by its theoretically unlimited (Section 3) nonfossil competitors, nuclear and solar power.
The answer to the second question, "How much fossil fuel is left in 2030?" is given in Table 11. There is, according to the sce- narios, quite a bit left, but it is not cheap, either financially, environ- mentally, or socially. And at the ever increasing consumption rates of the scenarios - already at 22.4 TWyr/yr t o 35.7 TWyrlyr in 2030 - it will not last forever. Again the scenarios' message is the same. During the next 50 years the crucial constraint is not likely to be the availability of resources; rather it will be time - the time needed t o reduce the demand for liquid fuels and the time it takes nonfossil technologies t o penetrate the primary energy market.
Primary liquids demand
Year
+#
Conventional
I oil (presently known reserves)
I
Figure 13. The oil supply and demand calculated for the regions with non centrallv planned economies from (a) the high scenario, (b) the low scenario
oil production
Lo[
3 Primaryliquid^^^^^
liquefaction, -
\!
Conventional Year oil (presently ,'i reserves) ,
I
1
0009 OOOLo m
' a o q l g i - z ~ $ i e I!O sapnpu! tll A.lo6aarr~ ie y i idaaxa '1 alqel 40 aooyi are sa!rofiaaea a q l 'o!reuws M O ~ ayi (q) 'o!reuaas y6!4 aqi (e) worj paielnqea puewap pus Alddns I!O leqo16 a y l '@L arn6!4
- 01
-
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h puewap sp!nb!l -
- AJelu!Jd IelOl -
ooaa
(a) Year
I
Figure 15. The global coal supply and demand calculated from (a) the high scenario, (b) the low scenario.
.
.
GWyrIyr 1 OOOC
800C
600C 400C
2000 Electricity
I! J L W U U J
b,k Year
TABLE 11 The cumulative uses of fossil fuels.
Resource (TWyr) High scenario Low scenario
Oil
Two important economic interpretations of the scenario results are displayed in Table 12 and Figure 16. The table shows how the projected growth in final energy consumption compares with the economic growth rates that were assumed at the beginning of the scenarios. The comparison is in terms of the final energy to gross domestic product elasticity (for definition, see the Appendix). The higher this number, the faster final energy use is growing in relation to the economy as a whole. If the value is greater than 1 .O, final energy use is growing faster than the economy; if the value is less than 1.0, the economy is growing faster. The numbers show that, as a general rule, as the scenarios move from 1975 t o 2030, less and less energy is needed to fuel economic growth; that is, the societies of the scenarios are becoming ever more conservationist. The only exception t o this trend is Region I (NA), because of its currently tremendous potential for conservation. The scenarios assume that this potential will be exploited quickly; in fact, a large part of the conservation occurring before 2000 is due simply to already man- dated improvements in the fuel efficiencies of Region I (NA) auto- mobiles.
The second important message of Table 12 is that, the more developed an economy is, the less energy it requires for economic growth. The elasticities for the developed Regions I (NA), I1 (SUIEE), and I11 (WE/JANZ) are all below 1.0 (the economy grows faster than final energy use), while for the developing regions the elasticities are predominantly greater than 1.0 (final energy use grows faster than the economy).
TABLE 12 Final energy to GDP elasticities, 1950-2030, for the IlASA high and low scenarios. Scenario projection Region
Historical 1975-1 985 1985-2000 2000-201 5 201 5-2030 1950-1975 High I Low High I Low High I Low High I Low 1 (NA) II (SU/EE) Ill (WEIJANZ) IV (LA) V (AfISEA) Vl (ME/NAf) Vl l (C/CPA) World
(% of GDP)
(a) Year
Figure 16. Direct plus indirect energy investments as a share of gross domestic product for developed and developing regions: (a) high scenario, (b) low sce- nario.
The capital investments required t o support the expanding energy supplies of the scenarios are indicated in Figure 16, which shows the percentages of the gross domestic product that must be invested in energy facilities. As might be expected, the situation is most difficult in the developing countries, where, in the high sce- nario for example, energy investments peak at 6.6% of GDP around 2020.
In addition t o the two benchmark scenarios, three alternative cases were also analyzed, though in less detail. As suggested by their titles, two of these - the nuclear moratorium case and the enhanced nuclear case - involved major changes in the assumptions concern- ing energy supply. The third alternative arose from a major change
6.0 -
5.0 -
( % o f 4.0- GDP)
Developed
1.0 -
(b) Year
on the demand side: What are the implications if we assume that the global primary energy demand in 2030 does not exceed 16 TWyr/yr (compared with the low scenario value of 22.4 TWyrlyr)?
The key characteristics of the three alternative cases turned out to be as follows.
The nuclear moratorium case indicates that the energy demands of the low scenario can indeed be met without new nuclear capacity. Fossil fuel supplies are depleted more alarmingly than in the low scenario, gas assumes an especially important role, and solar electric power expands at its maximum rate (see Section 2). Needs are met, but costs are higher than in the low scenario (Figure 17).
As the cushion of fossil fuels is diminished, time therefore becomes a tighter constraint.
In the enhanced nuclear case, in which energy demand is assumed to be at the same levels as in the high scenario, the unset- tling depletion of fossil resources, so characteristic of both scenar- ios and the nuclear moratorium case, is abated only slightly. Despite
8.0 -
7.0 - Developing Regions
0 0--
6.0 -
5.0 -
Developed Regions 4.0 -
-
Low Scenario IIa0
t
,,Nuclear Moratorium case YearFigure 17. The total energy investment as a share of the gross domestic prod- uct for the low scenario and the nuclear moratorium case.
the use of nuclear-generated hydrogen t o produce liquid fuels from coal efficiently, in 2030 only 14% of the liquid fuels produced are of nuclear origin, and the overall share of the global primary energy
the use of nuclear-generated hydrogen t o produce liquid fuels from coal efficiently, in 2030 only 14% of the liquid fuels produced are of nuclear origin, and the overall share of the global primary energy