◎ Science and Technology Daily reporter Li Shan
Recently, the "Northern Stream" natural gas pipeline that travels through the Baltic Sea between Russia and Germany is suspected of being damaged by man-made damage, and a large amount of natural gas continues to leak from four leak points. Because natural gas is rich in greenhouse gas methane, this leakage may have serious impacts on the environment and climate. Environmental groups call on all parties to take immediate measures to minimize natural gas leakage. On the other hand, the incident also sounded the alarm for the safety of critical infrastructure.
This aerial photo released by the Danish Ministry of Defense on September 27 shows a leak point of a "North Stream" natural gas pipeline. Xinhua News Agency (Photo provided by the Denmark Ministry of Defense) How much natural gas does
leak?
leaked natural gas may exceed 700 million cubic meters. The total length of the
" Beixi-1" and "Beixi-2" pipelines are about 1,250 kilometers, and the diameter of the pipeline is about 1.1 meters. It is simplified to a pressure of 100 bar and a temperature of 10 degrees Celsius. The natural gas stored in the four pipelines may be as high as 778 million cubic meters. Another simpler estimation method, at the end of 2021, Gazpromium Corporation announced that it had injected 350 million cubic meters of so-called technical gas into the " Nord Stream-2" pipeline, with a pressure of 103 bar. The natural gas pressure in the "Beixi-1" pipeline is even greater, and the reserves will exceed 350 million cubic meters. Together, there are at least more than 700 million cubic meters of natural gas in the "North Stream" pipeline.
The German Federal Environment Agency (UBA) believes that "the natural gas in the pipeline will likely overflow all" because there is no special shutdown mechanism in the middle of the pipeline. The damage occurs on seabed , which is tens of meters deep, and is difficult to repair in the short term. Experts believe that it is impossible to block the leakage point before all gases escape. UBA estimates that more than 300,000 tons of methane will be released into the atmosphere. The German Environmental Assistance Association estimates that the escape of methane may exceed 350,000 tons. and the worst case is that 778 million cubic meters of natural gas leaked, which is about 500,000 tons of methane. What does
mean to the climate and the environment?
natural gas is mainly composed of a mixture of gaseous low molecular hydrocarbons and non-hydrogen gases, including methane (85%) and ethane (9%), a small amount of propane and butane , etc. Methane is a gas that can destroy the climate more than carbon dioxide . According to data from the UN Intergovernmental Panel on Climate Change (IPCC), methane has more than 80 times the harm to the climate over a 20-year period. Looking at the same amount of data in 100 years, the loss is about 25 times. In the short term, the 300,000 to 500,000 tons of methane leaked by is equivalent to 24 to 40 million tons of carbon dioxide emissions.
Unlike oil spill accidents, methane is non-toxic, and part of it dissolves in water, but it will not pose a serious threat to the surrounding environment. Previously, natural gas leaks occurred during the oil and natural gas drilling process of Beihai , but no direct consequences were found to have been found to be caused to the marine environment. However, some studies say that methane is much more harmful to the climate than carbon dioxide, and the released methane will continue to encourage global warming of . When people are pursuing the need to minimize greenhouse gas emissions as much as possible, large-scale natural gas leakage is indeed a serious issue. In comparison, the auction volume of EU carbon dioxide emission rights in August 2022 was only 24.1 million tons.
However, this is only a small amount compared to the total global greenhouse gas emissions (40.8 billion tons of carbon dioxide equivalent) in 2021. As far as the leaked gas itself is concerned, its impact on global warming cannot be directly measured. Oliver Schmal, a researcher at the Baltic Institute in Leibniz, Germany, believes that the climate process will not change as a result. Even if 500 million cubic meters of natural gas escaped from the pipeline, it is only equivalent to about 18% of Germany's methane emissions in 2021, accounting for only 0.06% in global comparison. How to deal with the "North Stream" leak? To be honest, all parties concerned are basically helpless about the "Beixi" leak.The German Environmental Assistance Association called on pipeline operators and German regulators to “pull the remaining gas from all pipelines immediately”. Because the leakage caused "unestimated damage to climate protection". The Nord Stream pipeline is made of 12 cm thick steel covered with concrete and is mostly placed on a seabed 80 to 110 meters deep below sea level. According to the addition of a standard atmospheric pressure for every 10 meters of water drop, the air pressure will only reach 10 bar at a depth of 100 meters. But there is a pressure of at least 100 bar in the gas pipeline. Therefore, whether it is Russia or Germany, the feasibility of "pulling the remaining gas out of all pipelines" is not high. According to Leibniz Baltic Institute, it makes sense to ignite natural gas escaping above the water surface and convert it into carbon dioxide from a purely scientific point of view. Burning leaked natural gas is one way to reduce its damage to the climate. However, there are risks in this. In practice, there are also problems such as who will make decisions and how to operate. The most important thing about is that time waits for no one. The Danish Energy Agency said that half of the gas stored in the "North Stream-1" and "North Stream-2" gas pipelines have been discharged and is expected to be emptied on October 2. It is not clear when governments and experts from relevant countries will go to the field to detect the "North Stream" leakage and repair damaged pipelines. Danish said that for "safety reasons", the investigation will take as soon as one or two weeks. German officials warned that if cannot quickly repair the damaged pipeline, too much salty seawater will flow into and corrode the pipeline, causing irreparable damage. Chairman of the Russian Duma Energy Commission Zavalny proposed two maintenance plans: erecting caisson on the pipeline, and engineers operate in the caisson; or lifting the pipeline above the water surface for repair. He also said that the construction period for restoring the "Beixi" pipeline may take at least half a year to a year. What kind of warning can it bring to us? After the "North Stream" pipeline was artificially damaged, all countries have strengthened their control over territorial waters and monitored critical infrastructure more closely. Germany has also strengthened its protection of the North Sea and Baltic coastal areas, and listed the liquefied natural gas receiving station and submarine cable as key protection targets. It is worth noting that what the seabed needs to protect is not only natural gas and power lines, but also China Unicom's global Internet cable. At present, the total length of nearly 400 submarine cables connecting various continents exceeds 1.3 million kilometers.
As infrastructure lines, pipelines and cables have become the target of malicious attacks, the boundaries between peace, crisis and conflict are becoming increasingly blurred, and improving the security of various critical infrastructures has become a very important task. Infrastructure vulnerability issues should be paid more attention, and measures to protect energy supply, drinking water and digital infrastructure must also be implemented at a faster pace. Finally, and most worthy of warning, people must realize that the special attack on infrastructure, the Nord Stream pipeline is neither the beginning. It's not the end, either.
Edited by: Liu Yiyang
Reviewed by: Zhu Li
