Alaska pipeline

The ALESKA Pipeline, or trans-Alaska pipeline, or TAP, goes the entire length of Alaska from the very north to Valdez. It's 800 miles long and moves about 10% of Americas oil. It transports from as much as about 2.5 million to as little as 500,000 barrels per day, depending on demand. From Valdez, the oil is taken by ship to California and some to Texas through the Panama Canal.  Pipeline facts

Getting to stand by it and listen to how it works and why it is built the way it is can't be duplicated by a link.  We were treated to a short lecture about the pipeline as part of our visit to the gold dredge.   Wherever there is permafrost, the pipeline is above ground. Where there is no permafrost, it is buried. About half of the pipeline is buried.  The above ground portions are supported by vertical supports.



 

Here the pipeline is buried and what you see is the service road
going ovet the hill.

There was great concern about melting the permafrost and both altering the environment and destabilizing the support for thousands of miles of pipe. Here you can see that the pipe sits on an H shaped support. The center of the H is designed to move and the pipe rests on it. This is a provision to protect against earthquake and to allow the pipe to expand and contract. The pipe itself is 4-feet in diameter and what you see is the outer shell of an insulating layer that keeps heat in the oil so that it will flow. At the top of many of the H supports there is an aluminum radiator. There is a system in the H that carries heat away from the ground and radiates it into the air, protecting the ground from melting. There are sections of the pipeline that zig zag up and down hills. They serve to give the pipeline some springiness.

We just had to have some "we were there" pictures, so we snuck up against some of the supports and went click.  You can get some idea of how big this thing is.  By the way, it turns out that one of the great environmental concerns was not an issue.  Further north from where we are is the range of the largest Caribou herds in Alaska, over 500,000 animals.  There was concern that the pipeline would disturb their migration patterns and put them in serious jeopardy.  It turns out that the Caribou ignore the pipeline completely.

In the next picture, you can see the pipeline coming out of the hillside and passing by us.  We were at the No 8 Dredge historic park and part of the tour was a description of the pipeline.  The little house in the foreground provides what is called cathodic protection for the pipeline.  It keeps the pipe from rusting.  It turns out that it is also necessary to scrub the inside of the pipe to remove accumulated sludge.  To do this, they shuttle what is called a pig into the pipe and use the oil to push it along.  At various points in the pipeline are systems to introduce and remove these pigs.  An example of this is in the picture of a cutaway part of a section of pipeline pipe. 

This is a dumb pig, but now they use smart pigs that have instruments in them to inspect the pipe as the pig moves through it.