Environmental Engineering Reference
In-Depth Information
REDUCING THE IMPACT OF TRANSPORTATION
Freight transportation relies exclusively on petroleum to fuel fleets and to obtain lubricants that
are essential for transportation vehicles. Unfortunately at the moment there are no alternatives
to fossil fuels to operate the freight transportation sector in a realistic way. From a technical
viewpoint, railroads could be electrified and cargo trains operated similarly to electric passenger
rail systems. Still if zero carbon emissions is the goal, railroad electrification would be
contingent on the discovery of effective ways to produce electricity without burning fossil
fuels. Besides, this probably would be practical only in short routes close to urban developments.
Electrification of cargo trucks and ships would depend on the development of high-energy-
density and low-weight batteries, which no one knows if it will be ever be feasible. A cargo
plane operated by energy contained in a battery is hard to even think about at this point.
In theory, one day transportation fleets could be powered with biofuels, synthetic fuels,
electricity, or fuel cells operated with hydrogen. Still at the present time, these technologies
are not mature enough (e.g., hydrogen or synthetic fuels), not practical enough (e.g., electric-
ity accumulated in a battery bank), or their production scale is too small (e.g., biofuels).
Considering the lack of alternative to fossil fuels in the near future, the only action to take
to minimize the impact of transportation is to become more efficient in energy utilization.
Trucks
Fuel efficiency in trucks can be improved by taking operational and technical measures.
Operational improvements include optimization of the logistics, reduction of idling, reducing
speed, and proper maintenance. Fuel consumption of long-haul trucks can be reduced by tech-
nical improvements, which include long combination vehicles, reducing weight and increas-
ing volumetric capacity, increasing the engine efficiency, decreasing rolling resistance, and
reducing aerodynamic drag. Smaller trucks and vans used for distribution of food products
could benefit from hybrid technologies similar to the ones used today in passenger vehicles.
Operational improvements
Optimization of logistics is about transporting a product, or an assortment of products, with
the least consumption of fuel (which also correlates with reduced transportation costs) and
still fulfilling external constraints, such as maintaining product quality and timely delivery.
Management of logistics take place at two scales: global and regional/local. On a global scale,
logistics can be optimized by choosing the most efficient method to transport a product from
point A to point B while fulfilling the quality and time constraints.
On a regional/local scale optimization of transportation, which is generally done by trucks,
is about finding the best route from point A to point B that minimizes fuel consumption, which
in urban areas is sometimes a tradeoff between distance and idling time while stopped in traf-
fic. In many cases, the shortest route can be the most congested too, which increases idling.
Idling is one of the worst fuel efficiency killers because fuel is consumed while the displace-
ment of the vehicle is zero.
Another type of idling takes place in trucks equipped with sleepers. Drivers keep their engines
running to maintain the cab warm or cold or to provide energy for appliances and entertainment
systems while resting overnight. In cold climates, engines are often left idling to avoid difficult
starts and production of smoke during starting (Stodolsky et al., 2000), which can be solved by
installing electric block heaters to maintain the engine warm overnight in cold weather.
There are several approaches for reduction of idling to maintain services for the driver in
the cab/sleeper. Some of the technologies available are the use of direct-fired heaters, auxiliary
