Environmental Engineering Reference
In-Depth Information
1994 were banned and all 1994-2003 trucks were
also banned unless retrofitted. The goal is to have
100% Green compliance by 2012.
Apart from investing in vehicles with new
technology, cost reduction and eliminating waste
are proxies for Green initiatives. This is especially
important given the current economic slowdown;
where firms are focused on surviving let alone fo-
cusing on the environment. Such methods involve
route optimizing to minimize idling and avoiding
congestion; minimizing empty backhauls; moving
from less-than-truckload (LTL) to truckload (TL)
operations in order to minimize delivery layovers;
and switching transportation modes.
2
Still, post-WWII globalization has seen ac-
celerated growth in international ocean vessel
and air cargo operations. This has made national
regulation more difficult since these respective
carriers, unlike trucks and rail, traverse interna-
tional waters and multiple airspaces. As such, the
transportation sector occupies a unique position
in the United Nations Framework Convention on
Climate Change (UNFCCC). When the nations of
the world met in Copenhagen in December 2009 to
reach a consensus to reduce GHG emissions, the
U.N. International Maritime Organization (IMO)
and the International Civil Aviation Organization
(ICAO) were at the table as well and given admin-
istrative authority over their modes of transport.
But there is no agreed-to method as yet. Options
include a carbon tax, cap-and-trade, mandates for
Green technology, or combinations of the three.
Still, nations or trade blocs could opt for their own
regulations covering domestic harbors and airports
thereby creating a confusing patchwork. Of course,
there has never been a level-playing field. Since
the 1997 Kyoto Protocols, developed countries
were required to make binding commitments to
reduce GHGs while developing countries were
not. Then, as now, China and India are labeled as
developing; so if the United States or the European
Union is to lead, China and India need not follow.
The transportation process benefits from
run average costs as the scale of the operation
increases. Scale is achieved in a variety of ways.
For example, as a fleet increases in size the num-
ber of routes increases at a faster pace due to the
opportunity to interline vehicles at terminals or
hubs. Since operations increase as more route op-
tions become available, total costs are not rising
as fast as are operations; and this is a source of
economies of scale. This is the
raison d'etre
for
the less-than-truckload (LTL) trucking industry. Of
course, if a firm can manage to fill an entire truck
it may receive a bulk discount and enjoy faster
service. While that may reduce an individual firm's
carbon footprint, it may not have much of an effect
on that for the carrier's transportation network.
3
Lean manufacturing and just-in-time purchasing
rely on small but frequent shipments; therefore,
a carrier would need to operate in a LTL fashion
in order to fill vehicles. With minimal storage and
production only as needed, a producer's carbon
footprint is reduced but the carrier's is increased.
This is a perennial problem in logistics and supply
chain management: managing trade-offs.
Another important source of scale is vehicle
size. As vehicles increase in size the costs to op-
erate them do not rise as quickly. Think of how a
crew size would not have to double if the capacity
of an airplane, or number of boxcars attached to
a locomotive, were to double. Over all modes of
transport, size economies have been exploited
to the greatest degree in ocean vessel shipping.
Since fuel burn would not double if the number of
containers the vessel could carry were to double,
the ratio of pollutants per ton or per container
drops. Some large container vessels today employ
sails, burn liquefied natural gas, and some use a
waste heat recovery system which takes exhaust
gases from the engine and turn them into onboard
electric power instead of letting the exhaust escape
into the atmosphere.
A problem facing transportation planners is
how to arrange for backhauls. A consequence of
every front haul is a backhaul, whether loaded
