[Science World] Powerful Alternative to Save the Earth: 'Carbon Capture' Technology

A North Sea coastline 200 km off the coast of Norway. Here lies the world's first offshore Direct Air Capture (DAC) facility. This facility removes carbon dioxide mixed in the air. It is an artificial device aimed at preventing global warming. Some people argue, "Let's build many such devices to solve the global warming problem."

It sounds reasonable, but the reality is somewhat different. The technology that scrapes up carbon dioxide is commonly called Carbon Capture, Utilization, and Storage (CCUS), and there are different types of it. It is rare to find cases applying DAC like in Norway because its efficiency is low compared to the cost. Usually, the target is large amounts of carbon dioxide generated from factories or power plants. When the captured carbon dioxide is utilized in other industries, it is called CCU, and when it is buried underground for "storage," it is called CCS. Of course, carbon dioxide obtained through DAC can also be utilized or stored. This is why DAC is sometimes considered a type of CCUS and sometimes viewed separately.

Why utilize carbon dioxide if it is the main culprit of global warming? Carbon dioxide has many uses. When carbon dioxide is liquefied, it is called "liquefied carbon dioxide," which is widely used in welding, semiconductor production, food and beverage industries, and dry ice manufacturing. Without dry ice, it would not just be impossible to deliver ice cream; it would shake the foundation of the pharmaceutical and life sciences industries.

However, carbon dioxide used in this way eventually disperses into the atmosphere, causing global warming. The same applies to CCS. Although "storing" carbon dioxide sounds like it would prevent global warming, in reality, most of it happens during oil extraction. Carbon dioxide is injected into oil fields to increase pressure and extract oil, and finally, only carbon dioxide is left, and the entrance is sealed. Using the extracted oil then emits carbon dioxide again.

Of course, CCUS is not meaningless. It is positive in that it reuses carbon dioxide emitted from industrial sites. Since it is better than doing nothing, governments worldwide encourage CCUS. According to the International Energy Agency (IEA), CCUS projects supported by public funds worldwide increased to $20 billion (about 27 trillion KRW) in 2023. Therefore, people focus more on CCUS, which is more economical than DAC. Building DAC facilities only incurs ongoing maintenance costs, whereas CCUS can receive subsidies and resell the captured carbon dioxide, making it much more attractive.

This is not to say DAC is the best method. However, we do not have much time left. There are various efforts to reduce carbon emissions. It is time to try all-out various measures such as cultivating more forests and continuously increasing the share of renewable energy. Among them, DAC is a powerful and realistic card.

Norway boasts that its North Sea DAC facility removes about 1 million tons of carbon dioxide annually. So how much carbon dioxide does humanity emit in one year? In 2023 alone, it reached about 3.58 billion tons. Although this is an enormous amount, a simple calculation shows that building about 400 facilities similar to Norway's DAC could respond to global warming. It would not be easy, but it is not a number considered impossible.

Jeon Seung-min, Science and Technology Writer, Editor-in-Chief of Popular Science