Could underwater drones have damaged the Nord Stream pipeline?

As gas continues to spew out of the damaged Nord Stream pipeline into the Baltic Sea, questions are being asked about the reasons behind the leaks and who might be behind any deliberate attack.

A fourth leak on the Nord Stream pipelines was reported on Thursday off the coast of southern Sweden two days after three leaks were found to the underwater pipelines that carry gas from Russia to Germany.

Sabotaged is suspected, with one defence analysis suggesting underwater drones could have been used to damage the pipes. But officials have so far avoided pointing a figure directly at possible perpetrators of any sabotage, or speculated as to what damaged the pipes.

Neither pipeline was being used at the time, but if the leaks were caused deliberately, it raises worrying possibilities for other attacks on key underwater infrastructure, including communications cables and power lines, and raises the possibility of a hybrid war.

Were the pipes sabotaged?

Initial reports of leaks off the coast of Denmark on Monday were confirmed by Danish authorities, who released dramatic footage of the gas bubbling up from underneath the sea.

Swedish seismologists recorded what appear to be two loud explosions shortly before the leaks were discovered.

There appear to be three big holes - many miles apart - in the two pipelines – Nord Stream 1 and Nord Stream 2.

Experts said the distance between the three leaks and the fact both pipelines had been hit made it unlikely to be an accident. There was no earthquake or other event which could have caused a natural explanation for the leaks.

Officials have said there needs to be proper investigation into explosions that some see as deliberate sabotage by Moscow to exacerbate the energy crisis in the West.

But many have already formed their opinion. NATO Secretary-General Jens Stoltenberg attributed the leaks on the Nord Stream pipelines to acts of sabotage, in a tweet on Wednesday. A day later, he added a deliberate attack against allies’ infrastructure would be met with a determined response.

What is the impact of the leaks on gas supplies?

The Nord Stream 1 and 2 pipelines were not supplying gas to Europe when the leaks were first detected so in the immediate term, the leaks will not affect gas supply to Europe.

But it has been estimated that there may be up to 177 million cubic metres of natural gas still residual in Nord Stream 2 alone - the equivalent to the natural gas used by 124,000 UK homes in a year.

Maria Shagina, IISS Diamond-Brown Research Fellow for Economic Sanctions, Standards and Strategy said: “While the economic costs are zero, as both pipelines are non-operational, the prospects for future gas flows are equally zero. Russia's intention is to aggravate uncertainty around gas supplies before the heating season.

"The next piece of the puzzle is if, or rather when, Gazprom cuts supplies via Ukraine. Europe is gearing towards a scenario when Russia's gas supplies are halted, and it is entering a new chapter when the critical infrastructure is endangered.”  

How could the pipes have been damaged?

There is no evidence as to how the pipelines came to be so damaged, but experts suggested the leaks were “deliberate actions.”

Professor Joan Cordiner, Professor of Process Engineering at the University of Sheffield, said: “We can see from the width of the bubbles that the leak was sudden and very large, which is consistent with a large pipe being fully cut and not from normal corrosion we would see in operation."

Speaking on Wednesday before the fourth leak was reported, Swedish Prime Minister Magdalena Andersson said it would have taken a large explosive device to cause the damage.A US defence analyst who specialises in submarines and sub-surface systems, H.I. Sutton, put forward several theories as to how the pipes could have been damage, with one suggestion being underwater vehicles which could have been placed near the pipes "well in advance".

Other suggestions include explosives placed during construction phase; explosives placed inside the pipes, using Pigs (pipeline inspection gadgets); explosives laid by a surface vessel. He said torpedoes were "least likely".

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Who could be behind potential sabotage?

Experts have said Russia is likely to blame for any sabotage but Moscow denies this. Dmitry Peskov, the Kremlin spokesman, dismissed media reports about Russian warships spotted in the area as “stupid and biased,” and claiming that many more NATO aircraft and ships "have been spotted in the area.”

Fatih Birol, head of the International Energy Agency (IEA), told a news conference on Thursday it was “very obvious” who was behind the suspected sabotage of the pipelines, although he did not name anyone.

“It is not yet known who made it, who is behind this sabotage, there is still discussion more or less but ... it is very obvious ... who was behind this issue,” he said.

Anders Puck Nielsen, a researcher with the Center for Maritime Operations at the Royal Danish Defence College said it would be difficult to pinpoint who did it, if it was sabotage, calling it an example of "hybrid warfare".

He continued: "But I think if we look at who would actually benefit from disturbances, more chaos on the gas market in Europe, I think there's basically only one actor right now that actually benefits from more uncertainty, and that is Russia. Russia that is using gas exactly as a pressure point to sort of put pressure on Europe to essentially give up the support for Ukraine, in the Ukraine war."

Mr Sutton notes that "Russia has a long tradition of seabed warfare and has extensive investments in technologies."

What are the implications of the leaks?

The European Union on Wednesday warned of a “robust and united response” should there be more attacks and stressed the need to protect its energy infrastructure.

The UN Security Council has scheduled an emergency meeting on Friday afternoon at Russia’s request to discuss the suspected pipeline sabotage. 

Could other infrastructure be attacked?

Nick Childs, Senior Fellow for Naval Warfare and Maritime Security at think tank IISS said that whatever the reason behind the damaged Nord Stream pipeline, the incident highlights concerns "the potential vulnerability of undersea economic infrastructure, including pipelines and undersea cables, to attack or interference"."In some ways the threat is not new – and goes back to the start of using such undersea pipelines – but the scale of dependency on such infrastructure has increased, as well as the options to interfere with it, and the investments of some, like Russia, in capabilities to do so," he said.

"However, countering such threats particularly in a ‘grey-zone’ scenario of tension but nor direct confrontation, is difficult."  

Mr Childs added: "A number of governments, including the United Kingdom, are investing in vessels and other assets to improve undersea monitoring and surveillance, and organisations like NATO are focusing on this too.  It is also possible to increase the protection of particularly vulnerable elements of the infrastructure, like oil and gas platforms or the shore stations for data and communications cables."

Ms Shagina said: “Russia is stepping up its retaliation and burning all bridges to Europe", adding that, if this was sabotage, it was about weaponising energy infrastructure".

"It's no longer about gas leverage, but retaliation and punishment," she added.