The dozen or so fuel tanks resemble a patch of giant steel mushrooms along one of the busiest stretches of Interstate 65 in Alabama — just south of Birmingham in Pelham. Millions of motorists passing by have seen the tanks through the years, but the real story is what can’t be seen beneath them.
It’s a 5, 500-mile pipeline that runs from Houston to New York harbor and is the largest source of gasoline sold in Alabama. From the tanks in Pelham, product is pumped through a shorter underground line — a spur line — to a small group of supply terminals in western Birmingham. There, different oil companies mix their own additives before the fuel is trucked to final destinations.
The pipeline, owned by Colonial Pipeline of Alpharetta, Ga., delivers a daily average of 2.4 million barrels of gasoline and distillates, such as home heating oil, aviation fuel and other refined petroleum products, to terminals along its route. In 2011, the pipeline supplied 22.3 million barrels of gasoline to Alabama and 10.9 million barrels of distillates. Though sold to consumers by the gallon, gasoline is generally measured by the barrel, which equals 42 gallons.
The Colonial Pipeline also delivers fuel and distillates to the Anniston/Oxford area. A third and smaller line, operated by Plantation Pipeline, runs from Helena to a supply terminal in Montgomery.
The Colonial Pipeline consists of two lines traversing Alabama. One transports primarily gasoline and the other primarily diesel, jet fuel and home heating oil. The product is moved through the pipeline by a network of pumping stations and boosting stations, which add more horsepower for pumping where needed.
“(The product) travels at about the pace of a brisk walk, ” says Steve Baker, a spokesman for Colonial Pipeline. “The transit time, if you go from one end to the other, (Houston to New York) is about 16 days. The flow is different on different pipelines and determined by the amounts that have been ordered.
“The system requires a barrel to be delivered out for a new one to be put in, so the line is full all the time. But if orders go down, you pump at a rate to maintain the deliveries and keep the line full.”
The Colonial Pipeline minimum order, or “batch” size, is 75, 000 barrels, roughly 3.2 million gallons. It is common to ship different product grades in the same batch, although there is no physical separation of the grades in the line. Different grades in the line come in contact with each other at “interfaces, ” but the circular, “tubular” flow of the product minimizes mixing at the interface.
According to Baker, “If they are compatible products, we’ll cut the batch so that the higher-quality product goes into the lower quality product. For example, a shipment of high-octane gasoline will be cut to preserve the high-octane portion, and a bit of it will be left with the lower-octane gasoline that may be next in line.
“The higher quality product is preserved, and the lower quality product is enhanced. Interfaces that can’t be handled this way may be designated as a trans-mix, which is delivered off the pipeline to locations where it can be re-processed into useful product and re-transported to a customer.”
At the time the Colonial Pipeline project was announced in 1962, it was the largest single, privately financed construction project in U.S. history ($370 million). Initially requiring 1, 500 miles of pipe, made with 600, 000 tons of steel, the pipeline was expanded over time to its current size to meet ever increasing demand. Fifteen different contractors were each awarded work to install 100 miles of the pipeline, and the project was fully operational in 1963.
Given the scope of its logistics and the complexity of the industry it serves, the Colonial Pipeline is nothing short of an engineering marvel. As time goes on, however, monitoring and maintaining the pipeline take on greater importance.
The industry began using internal inspection devices in the 1980s to check for dents or corrosion in the pipeline, and those devices (often referred to as “pigs”) have become more sophisticated since their introduction. That helps Colonial Pipeline make better decisions about when pipeline sections need to be buried or replaced. Before new pipe is buried, for example, it is wrapped with protective coating to protect against corrosion.
Colonial Pipeline spent $75 million in 2011 on system integrity, which covers numerous programs to prevent corrosion, detect anomalies in the pipe and otherwise protect against leaks and spills. That same year, the company lost only 39 barrels of the 850 million barrels it transported, and of those 39 lost, all but eight were contained on Colonial premises.
“The rallying cry at Colonial is safety — not only the safety of the men and women operating the pipeline, but safety of the environment and the people we come in contact with, ” Baker says. “To us, safety means not getting hurt, but to the public, safety is more likely to mean no spills. Those twin challenges are at the heart of every business strategy we have. The other thing we like to note is that pipelines are reliable and efficient. Interruptions are rare, and we’ve learned how to cope with hurricanes and such natural disasters. We bring in our own portable power to get back into service and be available to our customers.”