Environmental Engineering Reference
In-Depth Information
1.1 Mobility Demands and Primary Energy Resources
Everywhere in the world, the acceleration of industrialization and economic
growth is accompanied by an increase of mobility demand, in particular in most of
the developing countries the requirements of mobility solutions able to drive the
pressing economic growth continues to outpace supply. In the last 20 years, the
number of cars and other vehicles is massively grown in many developed coun-
tries, while the vehicle ownership is rising at a rate of 15-20% annually in great
part of the developing world. Some recent projections show that some regions such
as Eastern Europe and Former Soviet Union are likely to reach OECD levels of
private transport by 2050, while China and Latin America will reduce the divide
significantly. Other regions, such as Africa, Middle East and rest of Asia should
see only small increase in their rates of personal mobility [
2
].
The worldwide increasing diffusion of environmental consciousness has
favored the affirmation of the sustainable mobility concept. This can be regarded
as the capability of a transportation system to meet the need of society to move
freely, improving the access of people to work, education and services, without
causing damages to the environment, as these could offset the socio-economic
benefits of accessibility improvements. This goal requires the development of new
strategies for enabling access to safer, cleaner and more efficient motorized
vehicles, public transit systems and transport infrastructures. All the concerns
which should be taken into account for the evaluation of sustainable mobility,
including the definition of a number of different indicators, have been the object of
specific programs, involving many worldwide automotive and energy companies
[
2
], and they will not reiterated here. This chapter will be instead focused on issues
directly connected to propulsion system technologies, starting in this paragraph
from a discussion on impact of increasing mobility demand on supply of transport-
related energy, in the context of overall primary energy availability.
Figure
1.1
shows the distribution of world energy consumption by sources in
2007 [
3
], it can be noticed that fossil sources represent the largest fraction of the
utilized sources (88%), with 36% for petroleum, followed by coal (28%) and
natural gas (24%). As almost 90% of the whole energy currently used in the
transportation sector derives from crude oil (petroleum), and about 65% of this raw
material is converted to fuels (the remainder goes to electric energy, building
heating, asphalts and chemicals), the main concerns regarding the availability and
environmental impacts of this fundamental primary energy resource have to be
discussed.
Petroleum has accompanied the industrial growth and the development of the
automotive market in the twentieth century. The reasons which have favored its
diffusion in substitution of coal are the higher energy density on mass basis (about
25% higher than coal) and its liquid state (easier and cheaper handling and
transportation). Until 1970s, the price of oil did not represent a problem, on the
contrary, it was an additional factor for affirmation of petroleum as energy source.
The first oil crisis at the beginning of 1970s brought out to attention of the great
