3.8.3 Historic Trends and Driving Forces
Table 3.28a categorizes fossil deposits into
reserves, resources and additional occurrences for both conventional and unconventional
oil and gas deposits. The categories reflect the definitions of reserves and
resources given above, with the exception that resources are further disaggregated
into resources and occurrences so as to better reflect the speculative nature
associated with their technical and economic feasibility (Rogner, 1997, 2000a).
Table 3.28b presents the global fossil resource data
of Table 3.28a in terms of their respective carbon
content. Since the onset of the industrial revolution, almost 300GtC stored
in fossil fuels have been oxidized and released to the atmosphere. The utilization
of all proven conventional oil and gas reserves would add another 200GtC, and
those of coal more than 1,000 GtC. The fossil fuel resource base represents
a carbon volume of some 5,000GtC indicating the potential to add several times
the amount already oxidized and released to the atmosphere during the 21st
century. To put these carbon volumes into perspective, cumulative carbon emissions
associated with the stabilization of carbon dioxide at 450ppm are estimated
to be at 670GtC. Figure SPM.2 combines the reserve
and resource estimates with cummulative emissions for various reference and
stabilization scenarios, taken from other chapters and the IPCC WGI report.
| Table 3.28b: Aggregation of fossil energy
occurrences, in GtC |
 |
|
Consumption
|
Reserves
|
Resourcesa
|
Resources
baseb
|
Additional
occurrences
|
|
1860-1998
|
1998
|
|
|
| |
| Oil |
|
|
|
|
|
|
| Conventional |
97.1
|
2.7
|
118
|
153
|
271
|
|
| Unconventional |
5.7
|
0.2
|
132
|
308
|
440
|
1,220
|
| Natural gasc |
|
|
|
|
|
|
| Conventional |
35.9
|
1.2
|
82
|
179
|
261
|
|
| Unconventional |
0.5
|
0.1
|
123
|
165
|
288
|
245
|
| Clathrates |
|
|
|
|
|
11,934
|
| Coal |
156.4
|
2.4
|
1,094
|
2,605
|
3,699
|
3,122
|
| Total fossil occurrences |
295.6
|
6.5
|
1,549
|
3,410
|
4,959
|
16,521
|
| |
| |
Potential coal reserves are large – of that there is little doubt. However,
there is an active debate on the ultimate size of recoverable oil reserves.
The pessimists see potential reserves as limited, pointing to the lack of major
new discoveries for 25 years or so (Laherrere, 1994; Hatfield, 1997; Campbell,
1997; Ivanhoe and Leckie, 1993). They see oil production peaking around 2010.
The optimists point to previous pessimistic estimates being wrong. They argue
that “there are huge amounts of hydrocarbons in the Earth’s crust”
and that “estimates of declining reserves and production are incurably
wrong because they treat as a quantity what is really a dynamic process driven
by growing knowledge” (Adelman and Lynch, 1997; Rogner, 1998a). They further
point to technological developments such as directional drilling and 3D seismic
surveys which are allowing more reserves to be discovered and more difficult
reserves to be developed (Smith and Robinson, 1997). The optimists see no major
supply problem for several more decades beyond 2010.
Estimates of gas reserves have increased in recent years (IGU, 2000; Rogner,
2000a; Gregory and Rogner, 1998) as there is much still to be discovered, often
in developing countries that have seen little exploration to date. The problem
in the past has been that there needed to be an infrastructure to utilize gas
before it could have a market, and without an infrastructure, exploration appeared
unattractive. The development of CCGT power stations (discussed below) means
that a local market for gas can more readily be found which could encourage
wider exploration. In the longer term, it is estimated that very substantial
reserves of gas can be extracted from the bottom of deep oceans in the form
of methane clathrates, if technology can be developed to extract them economically
With uranium, there has only been very limited exploration in the world to
date but once more is required, new exploration is likely to yield substantial
additional reserves (Gregory and Rogner, 1998; OECD-NEA and IAEA, 2000) (see
Table 3.28a).
The other major supply of energy comes from renewable sources, which meet around
20% of the global energy demand, mainly as traditional biomass and hydropower.
Modern systems have the potential to provide energy services in sustainable
ways with almost zero GHG emissions (Goldemberg, 2000).
The following sections focus on energy supply and conversion technologies in
which there have been developments since the Second Assessment Report and which
may be key to achieving substantial reductions in greenhouse gas emissions in
the coming decades.
On a global basis, in 1995 coal had the largest share of world electricity
production at 38% followed by renewables (principally hydropower) at 20%, nuclear
at 17%, gas at 15%, and oil at 10%. On current projections, electricity production
is expected to double by 2020 compared to 1995 and energy used for generation
to increase by about 80% as shown in Table 3.29 (IEA, 1998b).
- Coal is projected to retain the largest share with a 90% increase in use
from strong growth in countries such as India and China reflecting its importance
there, steady growth in the USA but a decline in Western Europe.
- Gas is projected to grow strongly in many world regions reflecting the
increasing availability of the fuel, with an overall increase of 160%.
- Nuclear power is projected to decline slightly on a global basis after
2010. Capacity additions in developing countries and in economies in transition
roughly balance the capacity being withdrawn in OECD countries. Few new power
stations will be built in many countries without a change in government policies.
IAEA projections for 2020 cover a range from a 10% decline to an optimistic
50% increase in nuclear generating capacity (IAEA, 2000a).
- Hydropower is projected to grow by 60%, mainly in China and other Asian
countries.
- New renewables have expanded substantially, in absolute terms, throughout
the 1990s (wind 21% per year, solar PV more than 30% per year); these are
projected to grow by over tenfold by 2020, but they would still supply less
than 2% of the market.
Table 3.29: Past and projected global
electricity production, fuel input to electricity production and carbon
emissions from the electricity generating sector
(Source: IEA, 1998b) |
| |
| Global electricity generation (TWh) |
|
| |
1971
|
1995
|
2000
|
2010
|
2020
|
| |
| Oil |
1,100
|
1,315
|
1,422
|
1,663
|
1,941
|
| Natural gas |
691
|
1,932
|
2,664
|
5,063
|
8,243
|
| Coal |
2,100
|
4,949
|
5,758
|
7,795
|
10,296
|
| Nuclear |
111
|
2,332
|
2,408
|
2,568
|
2,317
|
| Hydro |
1,209
|
2,498
|
2,781
|
3,445
|
4,096
|
| Renewables |
36
|
177
|
215
|
319
|
433
|
| Total |
5,247
|
13,203
|
15,248
|
20,853
|
27,326
|
| |
| Fuel input (EJ) |
|
| |
1971
|
1995
|
2000
|
2010
|
2020
|
| |
| Oil |
11
|
13
|
14
|
15
|
18
|
| Natural gas |
10
|
24
|
29
|
43
|
62
|
| Coal |
26
|
57
|
65
|
85
|
106
|
| Nuclear |
1
|
25
|
26
|
28
|
25
|
| Hydro |
4
|
9
|
10
|
12
|
15
|
| Renewables |
0
|
1
|
2
|
3
|
5
|
| Total |
53
|
129
|
146
|
187
|
230
|
| |
| CO2 emissions (MtC) |
|
| |
1971
|
1995
|
2000
|
2010
|
2020
|
| |
| Oil |
224
|
258
|
273
|
307
|
350
|
| Natural gas |
158
|
362
|
443
|
662
|
946
|
| Coal |
668
|
1,471
|
1,679
|
2,185
|
2,723
|
| Nuclear |
0
|
0
|
0
|
0
|
0
|
| Hydro |
0
|
0
|
0
|
0
|
0
|
| Renewables |
0
|
0
|
0
|
0
|
0
|
| Total |
1,050
|
2,091
|
2,395
|
3,155
|
4,019
|
| |
| Average emissions per kWh |
| |
| gC/kWh |
200
|
158
|
157
|
151
|
147
|
| |
