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Alternative Fuels for Transportation
11.1 Introduction
Air pollution and global warming arising due to the ever expanding use of
energy have become problems of global concern. Global atmospheric warming is now a generally accepted fact, although there is still debate on the
true nature of its origin. Concerns about climate change and the impact of
exhaust emissions and energy security have given the impetus to look for
alternative fuels/power sources for automotive applications. According to the
U.S. Environmental Protection Agency (EPA) Report, vehicles in the United
States account for about 75% of carbon monoxide (CO) emissions, about 45%
of nitrous oxide (NO x ) emissions, and nearly 40% of volatile organic compound emissions (Emadi et al. 2004). European countries contribute about
20% of the greenhouse gases from vehicular transport (Adcock, Kells, and
Jackson 2008).
The growing concerns on environmental issues have been constantly
demanding cleaner and energy-efficient vehicles without compromising
the convenience of the conventional internal combustion engine vehicles
(ICEVs). To meet these demands, major automotive manufacturers have
been attempting to introduce electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs) as alternatives
to ICEVs. However, such vehicles have several techno-economic issues
that need to be addressed. Among zero emission vehicles (ZEVs), batterypowered electric vehicles (BEVs) are the most viable alternatives. But BEVs
have several short-comings, namely limited electrical energy storage, long
charging time, small operating temperature range, low-cycling capability,
and high cost.
Fuel cells that can overcome the major technical limitations of the storage
batteries, namely their energy density, have shown promise for automotive
applications. A fuel-cell vehicle (FCV) uses a fuel cell stack as the source of
electric power to drive an electric-traction motor. Unlike internal combustion engines (ICEs), fuel cells are not limited by Carnot cycle and hence can
operate highly efficiently.
Various types of fuel cells are: alkaline fuel cells, phosphoric acid
fuel cells, polymer electrolyte fuel cells (PEFCs), molten carbonate fuel
cells, and solid oxide fuel cells. Among these, PEFCs are seen to be most
attractive for automotive applications due to their quick start-up and lowtemperature operation. A PEFC uses hydrogen as fuel and oxygen from
air as the oxidant. Ironically, however, hydrogen is not available freely in
nature and hence needs to be produced from other hydrogen containing
fuels. It is projected that the use of FCVs will help reduce the emission of
carbon dioxide gas by about 33% and there will be virtually no other polluting gases. In this article, we estimate the power and energy consumption of a modern car, and examine the feasibility of the PEFCs for realizing
a viable FCV.
Alternative Fuels for Transportation
11.1 Introduction
Air pollution and global warming arising due to the ever expanding use of
energy have become problems of global concern. Global atmospheric warming is now a generally accepted fact, although there is still debate on the
true nature of its origin. Concerns about climate change and the impact of
exhaust emissions and energy security have given the impetus to look for
alternative fuels/power sources for automotive applications. According to the
U.S. Environmental Protection Agency (EPA) Report, vehicles in the United
States account for about 75% of carbon monoxide (CO) emissions, about 45%
of nitrous oxide (NO x ) emissions, and nearly 40% of volatile organic compound emissions (Emadi et al. 2004). European countries contribute about
20% of the greenhouse gases from vehicular transport (Adcock, Kells, and
Jackson 2008).
The growing concerns on environmental issues have been constantly
demanding cleaner and energy-efficient vehicles without compromising
the convenience of the conventional internal combustion engine vehicles
(ICEVs). To meet these demands, major automotive manufacturers have
been attempting to introduce electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs) as alternatives
to ICEVs. However, such vehicles have several techno-economic issues
that need to be addressed. Among zero emission vehicles (ZEVs), batterypowered electric vehicles (BEVs) are the most viable alternatives. But BEVs
have several short-comings, namely limited electrical energy storage, long
charging time, small operating temperature range, low-cycling capability,
and high cost.
Fuel cells that can overcome the major technical limitations of the storage
batteries, namely their energy density, have shown promise for automotive
applications. A fuel-cell vehicle (FCV) uses a fuel cell stack as the source of
electric power to drive an electric-traction motor. Unlike internal combustion engines (ICEs), fuel cells are not limited by Carnot cycle and hence can
operate highly efficiently.
Various types of fuel cells are: alkaline fuel cells, phosphoric acid
fuel cells, polymer electrolyte fuel cells (PEFCs), molten carbonate fuel
cells, and solid oxide fuel cells. Among these, PEFCs are seen to be most
attractive for automotive applications due to their quick start-up and lowtemperature operation. A PEFC uses hydrogen as fuel and oxygen from
air as the oxidant. Ironically, however, hydrogen is not available freely in
nature and hence needs to be produced from other hydrogen containing
fuels. It is projected that the use of FCVs will help reduce the emission of
carbon dioxide gas by about 33% and there will be virtually no other polluting gases. In this article, we estimate the power and energy consumption of a modern car, and examine the feasibility of the PEFCs for realizing
a viable FCV.