Prudhoe Bay – The Pipeline

Even
if you’ve never heard of Prudhoe Bay, most people have heard of the Trans-Alaska
Pipeline–which is truly an engineering marvel.  Since the Arctic
Ocean at Prudhoe Bay is ice-free for only six weeks out of the year, the
pipeline was built to move North Slope oil from Pump Station No. 1 at Prudhoe
Bay to an ice-free port terminal at Valdez, Alaska, 800 miles to the south. 

The
pipeline is four feet in diameter, and built in most places about 5
feet above ground to allow passage of wildlife underneath.  The
line is also constructed in a zigzag pattern to allow for not only thermal
expansion, but also to allow non-destructive movement during one of
Alaska’s frequent earthquakes.  Fortunately, strong earthquakes
are fairly rare, but the pipeline is designed to allow 5 feet of vertical
movement and up to 20 feet laterally just in case. 

The
oil is helped along the line by a series of pump stations located, on
the average, about 75 miles apart.  Since the pump stations are
often located in remote areas far from power supplies, some of them
just tap energy from the pipeline itself! They have a small on-site
refinery to make jet fuel. The jet fuel is used to power a stationary
jet engine, which drives the pumps and acts as the station’s power plant.
However, the addition of friction-reducing agents to the oil, together
with reduced field production, have resulted in the mothballing of several
of the pump stations. 

The
oil takes about 5-1/2 days to make the trip all the way down the pipeline. 
When it reaches Valdez, it is loaded onto supertankers for transport to
either West Coast refineries, or since 1998, for possible export to Asian
markets.