The Trans-Alaska Pipeline System is the 800-mile long backbone of the state’s energy infrastructure.
It’s built to transport up to 2 million barrels of oil per day, but these days it carries only about a quarter of that.
With oil production at lower levels, how long will the pipeline be viable?
Alyeska Pipeline Service Company is exploring new ways to keep the system up and running.
The 36-year-old Trans-Alaska Pipeline marches south from the North Slope across squishy tundra, mighty rivers and high mountain passes on its way to Prince William Sound.
The system that monitors that pipeline is a bit less romantic.
“Well here’s a station control panel,” Mike Malvik, a senior processing engineering adviser for Alyeska Pipeline Services Company said, as he opened the door to a beige cabinet. “All these are now are a bunch of Ethernet cables for communications between the various programmable logic controllers.”
He takes me on a tour of the backrooms of the pipeline’s Operations Control Center in Anchorage.
“Upon pipeline start up there was a computerized control system, but it was a lot more primitive in that it used mechanical relay switches and vacuum tubes,” Malvik said.
Now, pipeline controllers sit in a quiet room filled with massive monitors. The screens show schematics that look sort of like 1980s video games. Symbols indicate which valves are open and the direction the oil is headed.
“Follow the blue line and the oil’s going to tank five today,” Malvik said.
Controllers monitor pressure, temperature, and flow. They respond to alarms and communicate with workers in the field. It’s extremely mellow during a normal day as the controllers try to keep the oil flowing at a steady state.
But Malvik explains that maintaining the steady state is harder when less oil is flowing through the system. With only about 550,000 barrels entering the pipeline per day, the oil gets colder much faster.
“And if you get to the freeze point then you can start making ice in the pipeline, coating critical valves, collecting in low parts of the pipe and then you have a cleaning pig pick up that ice and bring it into a pump station and plug that pump station up,” he said.
A cleaning pig looks like an 8-foot long shish kebab of mushrooms and quarters.
It scrapes the inside of the pipeline and pushes wax and ice out of the system.
The problem is, they only work if the oil moving fast enough to push them along. In the next few years, it may not be. Less oil makes leaks harder to detect as well.
So, how low is too low?
“We haven’t firmly landed on that number because we’re still studying it,” Malvik said.
Part of the study includes a new pipeline model decked out with all of the same types of monitors and equipment as the real pipeline, just in miniature. It’s being built at the University of Tulsa.
“What we’ve designed the test loop at Tulsa to do is simulate as closely as we can, if I was a drop of oil going from pump one to Valdez, what temperatures would I see, what terrain types would I see,” Malvik said.
Starting this month they’ll run oil from the North Slope through the model. They want to test new ideas like dry-flow.
It’s deceptively simple.
Oil pumped from the ground naturally contains water. If you let it sit in large tanks for a few hours, the water drops out. Less water in the oil could solve problems like ice build up and pipe corrosion.
Lois Epstein is a petroleum engineer with the Wilderness Society and vice president of the Pipeline Safety Trust. She says studying the technical problem is the best solution to the low flow issue.
“From my perspective as an engineer, the things they’re looking at right now seem to make a lot of sense,” Epstein said.
Epstein says she trusts that Alyeska, which operates the pipeline on behalf of it’s owners, has motivation to find a way to keep TAPS running for decades to come.
“The major operators on the North Slope don’t want to leave the crude in the ground. They’ve already done the exploration. They’ve set up the pipeline infrastructure. They want to see it go to market. So from a commercial standpoint, an economic standpoint, they’re going to make sure that TAPS is viable over the long run,” Epstein said.
From an environmental stand point, she would rather the companies make use of the infrastructure and oil fields that are already there instead of developing new ones in places like ANWR.
As Alyeska waits for the study results, they are dealing with the low flow problem by adding extra heat to the oil. They have restarted some pump stations where they cycle the oil through multiple times. The friction heats up the oil before heading back down the line.
Another possible solution is storing oil in tanks at Pump Station One and only running the pipeline part time. But Malvik says starting it and stopping it in the winter has problems of it’s own.
“We don’t have all the answers now, but we are working on them. And we we’re working on them very thoroughly because we can’t afford to get them wrong. We have to get them right,” Malvik said.
He’s hoping the answers from Tulsa will help the pipeline run efficiently – and safely – far into the future.