Tag Archives: transportation efficiency

Crude Movements

It seems that oil pipelines are in the news of late. Some of the new pipelines are to deal with the expanded production of crude oil here in the US. New and better technology – hydraulic fracturing (fracking) and directional drilling have resulted in the need for transportation of that oil, pipelines generally being the cheapest.

We produce about 10 million barrels of crude oil per day and import another 10 million barrels from sources all over the world. Most of this is turned into fuels such as gasoline and diesel fuel and only a pittance for non-fuel petrochemicals.

But are pipelines the best way to go? Other methods to move the crude oil from where it is produced to where it is refined include barges, rail cars and tank trucks. What is the best way to do it? It depends entirely on what metric you use to measure “best.”

If you simply want to compare the least oil spilled when normalized for amount of total oil transported per distance moved (ton/mile) the ranking is barges and tankers are better than rail is better than pipeline is better than truck.

If your metric is human deaths and property destruction we get a different rank: barge is better than pipeline is better than rail is better than truck. How about environmental damage? Because aquatic environments are more sensitive the ordering becomes: Rail is better than truck is better than pipeline is better than barge.

Oh but it gets more confusing, because so much of the crude oil moves by pipeline, about 70%. Another 23% by barge and tanker, trucking 4% and rail transport a mere 3%.

If a decision were made to go to more trucking for example the change for the better (or worse) would not necessarily be linear. More trucking would mean more congestion, hence an increased risk of untoward events even after adjusting for total oil moved.

There is already some evidence of the non-linearity of change. From 1975 to 2012 trains were much shorter and had very few spills, but the recent oil boom means a higher proportion of oil moving by train. Because of longer trains and more frequent crashes, more oil was spilled in 2013 alone than the previous 37 years.

It is just not a simple “what is the best.” This conundrum is reminiscent of a senate hearing back in the 1970s. Ed Muskie was conducting a hearing as to the risks of the supersonic Concorde flying over the United States. The committee’s chief scientist said, “Senator, we’re ready to testify,” and Muskie responded, “Okay, tell me what the answer is. Is this going to be a danger?” The scientist responded “I’ve got these papers here that definitely tell us this is going to be a danger.” Muskie was ready to conclude right there, but then the NAS scientist interjected, “On the other hand, I have another set of papers over here that says these papers aren’t good enough to know the answer.” Incredulous, the senator looked up and yelled, “Will somebody find me a one-handed scientist?!”

A one-handed scientist may produce a simple answer, but it won’t necessarily be the only or best answer.

Transportation Resistance

From Galileo to Elon

Over 400 years ago as the story goes, circa 1590, Galileo performed a scientific experiment which has been reproduced in schools across the planet to this day. Galileo went to the iconic leaning tower of Piza and dropped two balls, one larger and heavy than the other. As everyone knows, they hit the ground about the same time. This disproved Aristotle’s hypothesis that heavier objects fall faster.

What both Galileo and Aristotle were not considering was an aspect of fluid dynamics – air resistance. Basically air is a fluid and it gets in the way of movement. Anyone who rides a bike or paddles a canoe knows it’s a lot harder with the wind at your face; that is, greater air (or wind) resistance. Even if the air is standing still, it still gets in the way and slows things down. The faster you go, the more important the wind resistance becomes.

A bicyclist can make about 15 to 20 mph without too much difficulty but more than that is a problem due to drag. Get rid of the drag and the sky is the limit. Cyclists have attained well over 100 mph riding behind vehicles outfitted with a fairing to shield the cyclist from wind resistance.

In years past when fuel costs were low, the extra energy expended to overcome wind resistance was not important in motorized vehicles. It is today and will continue to become more important as fuel costs rise. Nowhere is wind resistance, that is aerodynamic drag, more important than in the trucking industry.

The first effort in the industry was the addition of fairings over the cabs of 18-wheelers which resulted in a 15% increase in fuel efficiency. A more recent innovation is the addition of side skirts on each side and between the wheels of big rigs, which have been shown to improve fuel efficiency by 5 to 15 percent depending on design. Finally “trailer tails” are being added to extend the saving another 5%. All together this add up to over 30% fuel savings, with payback times of a about a year for fleet vehicles.

Small steps to save fuel or increase speed result from reducing drag, but what if you could completely eliminate drag by eliminating the air itself? Listen up. Elon Musk is the billionaire savant who produces the wildly successful Tesla electric car. He also pioneered private industry space flight with his SpaceX company, which is regularly delivering supplies to the International Space Station orbiting above earth.

Mr. Musk has proposed building giant evacuated tubes into which transportation vehicles could attain speeds in excess of a thousand mph. These tubes would work just like the little canisters that deliver your checks and cash back and forth from the bank window to the remote drive-up station. The only difference is that people or bulk goods would go in the canisters, and travel thousands of miles at thousands of miles per hour. He has suggested that eventually an underground transportation network could transport people from New York to Los Angles in 45 minutes! That requires a speed of about 4,000 mph.

Transportation Efficiency

Prices for transportation fuels are down for the short term but will rise, and hence the costs for transportation of all the commodities we consume will rise. Transportation costs can be reduced in a couple of ways. Reduce the distance goods must be transported and increase the efficiency of transporting goods. Additional costs to consider are things such as the impact of greenhouse gas emissions and traffic fatalities associated with each transportation modality.
Increased reliance on locally-produced foods, among other goods, is a commendable goal. Not only does this strategy reduce transportation costs, but also builds community by supporting a local economy. This can go only so far, however, as some goods simply can’t be produced locally. Oranges will still need to be shipped to Vermont and maple syrup to Florida.

Transportation efficiency is best compared by using a figure called the ton mile-per-gallon; that is, the distance one ton of freight can be hauled with the consumption of one gallon of fuel (diesel). The numbers are for barges 576, rail 414, and trucking 155. An efficiency ratio is something on the order of 4:3:1 respectively. Barges are four times and rail transport three times as efficient as trucking. Data on barge traffic is included for the sake of comparison, but inland waterways are limited to essentially the eastern half of the U.S.

Not only is trucking the least efficient and most polluting, but also the most dangerous. An interesting statistic is fatalities per ton-mile. How many people will die as a result of the transportation of goods per billion ton miles? For barges .03, rail .65 and trucking 4.35. There are about seven times as many fatalities associated with trucking compared with rail transport.

Just as barges are limited to a large degree to the eastern U.S., rail transport has its limitations. Rail networks are not nearly as extensive as the highway system plus truck transport generally results in a faster delivery schedule.

The best solution to increase efficiency, increase safety and lower pollution due to transportation would be a much better integration of rail and truck transport. The objective would be to move freight long distances by rail, then use the trucking industry for the depot to retail outlet part of the haul.

Infrastructure changes are needed to expand the rail systems, meaning greater costs, but this would be offset by lower costs for highway construction and maintenance. Transportation safety would be greatly increased by getting most of the long haul trucks off the highway, thus reducing the number of truck car collisions.

There would still be a need for the trucking industry to move goods from an expanded rail system but these trips would be made with smaller trucks and for shorter distances. Trucking jobs would be more attractive because short haul trucking means that the drivers get to go home daily. Greatly increased integration of the trucking and rail industries can result in lower costs, cleaner air, and greater safety.