Trans-Alaska pipeline in danger due to permafrost melting


The Trans-Alaska Pipeline in the Interior of Alaska. Font – Gillfoto, CC SA 4.0

The permafrost thaw threatens to undermine the supports that hold an elevated section of the Trans-Alaska Gas Pipeline, endangering the structural integrity of one of the world’s largest pipelines.

In the worst case, a possible rupture of the pipeline would result in an oil spill in delicate and remote landscape where it would be extremely difficult to clean it.

A slope where an 810-foot-long section of the pipe is secured has begun to slip due to the permafrost melting, in turn, causing the keys containing this section of the pipe to turn and fold.

In accordance with NBC News, it appears to be the first time pipeline supports have been damaged by the “slope creep” caused by permafrost thawing, records and interviews with officials involved in pipeline program management.

To combat the problem, the Alaska Department of Natural Resources has approved the use of about 100 radiators (tubes that suck heat from the permafrost) to keep the icy slope in place and prevent further damage to the support structure. the pipe.

“The proposed project is comprehensive for the protection of the pipeline,” according to the November 2020 department analysis.

There is some concern about the use of these cooling pipes: they have never been used as a defensive protection once a slope has started to slide and the permafrost is already thawing.

Dalton Road in July 2014, with Trans-Alaska-Pipeline near Finger Mountain. Image – Mison, CC SA 3.0

The irony behind the use of radiators to defrost permafrost

According to the Journal of Commerce, the concept behind radiators is simple. An aluminized metal tube up to eight inches in diameter is filled with pressurized liquid carbon dioxide.

The tube is buried vertically with much of the device sunk underground. CO2 at a pressure below zero boils to -30 ° C and begins to evaporate, rising as it vaporizes and extracts heat from the ground.

The coldest CO2 condenses into liquid, lowers and continues the cycle, without the need for external power or moving parts. And that seems to be the irony we write Inside Climate News.

The Arctic and Alaska are warming twice as fast as the rest of the planet due to global warming. And global warming is driving the permafrost thaw that the oil industry needs to keep frozen to keep the infrastructure that allows it to extract more fossil fuels that cause warming.

On June 27, Digital Journal reported a study presented at Document of May 31 a The cryosphere, a publication of the European Union of Geosciences. The study focused specifically on Alaska’s infrastructure, including the Trans-Alaska Gas Pipeline.

The researchers found that roads, bridges, pipelines and other types of infrastructure in Alaska and elsewhere in the Arctic will deteriorate faster than expected due to the impact of the structures on the adjacent permafrost.

This crossroads at the Richardson Road it is close to the surface and is used radiators, special heat pipes that conduct heat from the oil to the fins at the top of the pipes to prevent thawing the permafrost. Font – Beeblebrox, CC SA 3.0.

The researchers focused on a portion of Dalton Road on the northern slope of Alaska, about 10 miles south of the Prudhoe Bay oil fields. The road runs parallel to the Trans-Alaska Pipe System,

When permission was requested in February 2020 to install radiators on the northwest slope of Fairbanks, near Dalton Highway in the central part of the state, the Alyeska Pipeline Service Co., which operates the pipeline , confirmed that thawing the permafrost posed a threat.

It should also be noted that there are about 124,000 radiators fixed along the route of the pipe, a gesture by its engineers to the importance of keeping the ground under its frozen.

The tubes are bored 15 to 70 feet toward the permafrost in areas where heating can cause it to thaw. But these refrigerators only cool the permafrost directly below the pipe, which contains the supports.

This latest project, which began last month, will try to freeze the thawing permafrost to prevent a wider slope from collapsing or slipping and damaging the supports.

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