Environmental Engineering Reference
In-Depth Information
Table 1.1 Previsions of IEA
for world energy demand by
fuel until 2030
Fuel
2006
2010
2020
2030
Mtoe
a
Oil
4000
4200
4700
5100
Coal
3100
3500
4300
4900
Natural gas
2500
2750
3150
3750
Biomass
1150
1250
1500
1650
Nuclear
750
800
850
900
Hydro
250
270
300
400
Other renewables
40
90
150
250
Adapted from Ref. [
1
]
a
Million tons of oil equivalent (one TOE = 11630 kWh)
Table 1.2 Previsions of IEA
for world energy-related CO
2
emissions until 2030
Country
2006
2010
2020
2030
Billion tonnes
OECD
13
15
14
16
Non-OECD
15
16
23
26
World total
28
31
37
42
Adapted from Ref. [
1
]
very significant fraction if compared to the contribution of other economic sectors,
such as power generation (37%) and industry (17%) [
1
].
On the other hand, when environmental issues due to the human mobility are
considered, the specific aspect of global CO
2
emissions cannot be disjoined by the
evaluation of other environmental impacts at local level (especially in metropol-
itan areas, as well documented worldwide) connected to pollutant emissions typ-
ical of the internal combustion engines, which represent the current and mature
technology the road transportation means are almost totally based on.
The question of primary energy reserves is of fundamental importance not only
from the general point of view of energy supply necessary to the economic growth,
but also for the transportation sector, which is strongly dependent on fossil fuels
availability. Both spark and compression ignition engines are currently fueled with
carbon-containing fuels deriving from fossil sources (oil or natural gas), and are
continuously improved in order to meet the always more stringent legislative limit
on pollutant emissions.
However, the above-mentioned significant contributions to the greenhouse
effect of the transportation sector, the always present environmental issues in
urban areas, and the foreseeable scarcity of fossil fuels in some decades, strongly
drive the interests of private and governmental research centers towards the study
of novel propulsion systems, able to face the cited problems.
The next paragraphs in this chapter will examine in detail the issues anticipated
in these preliminary remarks, paying particular attention to the driving forces
towards the possible affirmation of hydrogen as an energy carrier in incoming
years: (i) the limitation of oil reserves, (ii) the necessity of ulterior reduction in
pollutant emissions from road vehicles to meet the more and more severe legislative
limits, (iii) the need of lowering the CO
2
emissions to control the greenhouse effect.
