Do You Know 'CCUS' That Prevents Global Warming and Conserves Resources... Killing Two Birds with One Stone? [Reading Science]

[Asia Economy Reporter Kim Bong-su] Carbon dioxide (CO₂) is currently humanity’s common enemy. Labeled as the main culprit of climate change, governments worldwide are desperately striving to reduce carbon dioxide emissions. However, beyond merely cutting emissions, there are also active efforts to repurpose carbon dioxide as a “second oil” resource through a reverse-thinking approach. The resource utilization of carbon dioxide, known as CCUS (Carbon Capture, Utilization & Storage) technology, is already being commercialized in some fields and is rapidly emerging as another form of renewable energy for humanity.

◇ The Transformation of Carbon Dioxide is Innocent

On the 25th of last month, at a laboratory in the Korea Research Institute of Chemical Technology (KRICT) in Daejeon, a researcher operated a complex machine, causing a transparent bottle to begin filling with a yellow substance. This substance is naphtha, which is currently obtained only by refining petroleum. It is an essential resource often called the “rice of industry” because it is used as a raw material for gasoline and various plastic products. According to KRICT, this machine is designed to capture carbon dioxide from by-product gases generated during steelmaking processes and convert it through a transformation process to produce naphtha. The greenhouse gas, which is the main cause of global warming as it is emitted when animals breathe or carbon fuels burn, has been transformed into a “second oil.”

Until now, carbon dioxide has been treated as waste after use, with the best-known method being its sequestration underground, underwater, or in oil fields. However, as climate change has become more severe recently, CCUS technology?which can reduce the absolute amount of carbon dioxide in the atmosphere in the short term to slow warming and can be used as a resource to replace petroleum in the future?is rapidly advancing as a “two birds with one stone” solution.

Jeon Gi-won, head of the Next-Generation Carbon Resource Research Group at KRICT, said, “In the future, fossil fuel prices will rise, and the prices of fuels and materials utilizing carbon dioxide will fall, causing a reversal. Right now, the issue is not economic feasibility but the urgent need to actively develop and commercialize CCUS technology for carbon neutrality.”

◇ Limitless Utilization Technologies

Carbon dioxide is mainly generated after using fossil fuels, biomass, or during industrial processes such as steelmaking and power generation. Of course, it is also present in large quantities in the air. The process of converting it into useful products through chemical or biological transformation is called “conversion technology.” It can be used for fuels (methane, methanol, gasoline, diesel, aviation fuel), chemicals (polymers, chemical intermediates), and building materials (aggregates, cement, concrete).

Specifically, when carbon dioxide reacts with hydrogen (H₂) using electricity and catalysts, substances that can replace fuels derived from petroleum are obtained. When epoxides react with carbon dioxide, polymer materials are formed, which can be used for various plastics, foamed rubber, resins, and other materials. Carbonates produced by reacting carbon dioxide with steel slag or coal ash can replace limestone, a raw material for cement. There are also technologies that use carbon dioxide without conversion. Carbon dioxide is used as a solvent for enhanced oil recovery (EOR), for decaffeination, and dry cleaning. It is also used as a heat transfer fluid in refrigeration, air conditioning, and supercritical power generation, as well as in food and beverage, welding, and medical applications.

◇ How Far Has Commercialization Come?

Research on producing carbonates from carbon dioxide for use in building materials such as concrete has already entered the commercialization stage. Companies like CarbonCure and Solidia Technologies in the United States have already started producing building materials using carbon dioxide. In Korea, CO₂-reducing waterproof cement and mine-filling materials have been developed and are at the commercial stage. During the 2018 Pyeongchang Winter Olympics, precipitated calcium carbonate (PCC) paper made using carbon dioxide instead of limestone filler used in paper manufacturing was used for the event. The process of converting carbon dioxide into polymers, raw materials for plastics, has also begun commercial production at companies like Asahi Kasei in Japan.

On the other hand, chemical product conversion and fuel production are just moving beyond the laboratory stage and entering the demonstration phase. The market for utilizing carbon dioxide as a resource is growing steadily. In 2016, the Global CO₂ Initiative predicted that by 2030, 7 gigatons of carbon dioxide annually would be used as various resources. This is 3 to 10 times more than the 0.57 to 1.87 gigatons annual demand forecasted by the non-profit research institute GCCSI in 2011.

◇ Challenges to Overcome?

The main issue is economic feasibility. Although CCUS technologies using expensive catalysts such as platinum and iridium were developed initially, their high costs have led to the development of technologies that use cheaper materials like iron oxide or recycle small amounts. Also, with current technology levels, improving economic feasibility often requires input of energy from fossil fuels or existing petrochemical products, which reduces the contribution to carbon emission reduction. Experts explain that although polymer production, which is already in the early commercialization stage, has symbolic significance, its actual emission reduction impact is not large. Aggregate production using waste slag has a low entry barrier and can reduce carbon emissions from cement production, making it suitable for the early stages of the CCUS market.

Power-to-X (P2X), which converts carbon dioxide into chemical products and fuels, is especially attracting attention. The European Union (EU) is so committed that it included P2X in its 2050 carbon neutrality scenario. Producing naphtha by reacting carbon dioxide to convert it into chemical products and fuels can reduce greenhouse gas emissions by 3.51 million tons annually when producing 2 million tons per year, demonstrating excellent effectiveness. Given current technological development, it is expected that by around 2050, production costs will be about 90% of petroleum-based products, requiring steady investment.

Currently, South Korea consumes about 63 million tons of naphtha annually, of which 40 million tons are used as fuel oil. Using naphtha produced by P2X can achieve the dual effect of reducing greenhouse gases and substituting petroleum. Experts analyze that importing P2X naphtha is more efficient in terms of transportation and storage than importing green hydrogen such as ammonia from overseas.

Jeon said, “The challenges remain to lower catalyst costs, improve process design and reactors to increase efficiency relative to energy input, and scale up to mass production processes. Just as electric and hydrogen vehicles are being promoted with government support to achieve carbon neutrality goals, carbon dioxide resource utilization technologies are in a similar situation.”