Environmental Engineering Reference
In-Depth Information
can be used to assist in propelling the vehicle at a later time. Together, these effects result in fuel
consumption reductions on the order of 30% (Jones 2008).
Electrified vehicles, including “plug-in” hybrids, “extended range” hybrids (e.g., GM's
Chevrolet Volt), and full electric vehicles (e.g., Nissan's Leaf), can use electrical energy from
the municipal power grid for vehicle propulsion, directly displacing energy produced from
the liquid-fueled IC engine. However, despite high mile per gallon (MPG) ratings based on
fuel from the tank, the overall energy conversion process from source to wheels must still be
considered. When analyzing the electrical generation processes, it is found that nearly 70% of
the source energy is wasted (EIA 2006a), and furthermore, 71% of the U.S. electrical power
production is from fossil fuels (EIA 2006b). Considering this, it becomes clear that even when
electricity is used as the primary source for power, these vehicles are still contributing to the
depletion of fossil fuels and the increase of atmospheric carbon dioxide (CO
2
). However, as the
penetration of renewable sources of electricity production increases, including raw biomass,
biomass-based syngas, hydroelectric, solar, and wind, these vehicles will certainly show added
benefit. Nevertheless, debate will likely remain as to whether electrified vehicles running on
electricity generated from renewable sources or conventional vehicles running on renewable
liquid fuels is the optimal long-term solution.
10.1.1 u.S.
and
w
orld
t
ranSportation
f
uEl
u
SagE
Transportation fuel usage continues to increase worldwide. Transportation accounts for almost
30% of the total global energy delivered in 2007, making up more than 50% of global liquid fuel
consumption (EIA 2010). Of the 97.9 quadrillion (10
15
) Btu (103 quadrillion kilojoules) of energy
consumed for transportation in the world, the United States uses nearly 30% of this (EIA 2010).
To put this into perspective, if the petroleum used for transportation in the United States in 1 day
was placed in 55-gallon oil drums, and these drums were placed next to each other, they would
form a line from New York to Los Angeles, passing through Detroit and Houston (Figure 10.2).
Petroleum makes up the largest portion of transportation energy consumption, providing nearly
End:
New york
Detroit
Start:
Los angeles
Phoenix
El Paso
Houston
FIGure 10.2
Schematic representation of fuel used for transportation in the United States in one day as
barrels of fuel lined up end to end across the nation.
