[Report] "Coal Power Plants Grow Vegetables and Make Sparkling Water"... The Magic of CCU

Korea Midland Power's Boryeong Thermal Power Plant
Capturing and Liquefying Carbon Dioxide from Exhaust Gas
Utilized in Facility Horticulture and Carbonated Water Production
A Key Technology for Achieving Carbon Neutrality
High Costs Hinder Expansion... "Government Support Is Urgently Needed"

On May 23, I visited the Boryeong Thermal Power Plant of Korea Midland Power in Boryeong, South Chungcheong Province. Two liquefied carbon dioxide storage tanks, labeled in large letters as "for food and beverage use," were placed side by side outdoors.

"Each tank holds 450 tons of liquefied carbon dioxide. We produce between 120 and 150 tons per day. In eight days, both storage tanks are filled," explained Choi Seungyeol, Head of the Chemical Technology Department at the 3rd Power Plant of the Boryeong Generation Headquarters, who guided us around the facility. He added that once the liquefied carbon dioxide storage tanks are full, external companies with purchase contracts come to collect the product.

The liquefied carbon dioxide produced in this way is used for facility horticulture to promote crop growth, welding gas, dry ice production, and carbonated water manufacturing. Supplying carbon dioxide to greenhouses during the day stimulates photosynthesis, allowing plants to grow better. The "for food and beverage use" label on the liquefied carbon dioxide tank indicates its high purity, and it has been certified by a global food and beverage company.

Liquefied carbon dioxide storage tank installed at Boryeong Thermal Power Plant of Korea Midland Power Co. Photo by Heejong Kang

The raw material for liquefied carbon dioxide is the exhaust gas from units 7 and 8 of the Boryeong Thermal Power Plant, located right next door. Korea Midland Power has installed a carbon capture and utilization (CCU) facility that captures carbon dioxide from a portion of the exhaust gas from the thermal power plant and then liquefies it. The capture facility was completed in 2013, and by 2017, facilities for compression and liquefaction were also established. The CCU facility at Boryeong Thermal Power Plant is 10MW-class, making it the first and largest of its kind in Korea.

Carbon capture technology is a core technology for responding to the climate crisis and achieving carbon neutrality. It is essential not only at coal-fired power plants but also in industries such as steel, cement, and petrochemicals, where carbon dioxide emissions are unavoidable, in order to realize carbon neutrality. This technology is also used to capture carbon dioxide generated during hydrogen production from natural gas reforming. However, carbon capture technology in Korea remains at an early stage. The domestic technological level is estimated to be about 80% of that of advanced countries.

The carbon dioxide capture facility at Korea Midland Power was originally part of a government policy project involving Korea Electric Power Corporation, five power generation companies, private enterprises, and academia. Even after the project was completed in 2021, the facility has continued operation and is being used for various research and development projects, such as deep-cold capture technology using LNG regasification cold energy and the production of Greenol, a high-value-added fuel converted from captured carbon dioxide. To date, the facility has achieved over 10,000 hours of long-term continuous operation.

10MW-class carbon dioxide capture facility at Boryeong Thermal Power Plant of Korea Midland Power. Photo by Heejong Kang

To capture carbon, the power plant exhaust gas is sent to an absorption tower. When an amine-based absorbent is sprayed from the top of the absorption tower, the absorbent selectively captures only the carbon dioxide.

Next, when high-temperature steam is supplied in the stripping tower, the carbon dioxide is released again. The separated carbon dioxide is then compressed, refined, and cooled to produce liquefied carbon dioxide, completing the entire process. The facility at Boryeong Thermal Power Plant has a capacity of 200 tons per day and can produce up to 150 tons per day, or 35,000 tons of liquefied carbon dioxide annually.

The key to carbon dioxide capture technology is the absorbent. The efficiency of carbon dioxide capture depends on the performance of the absorbent. Depending on whether the absorbent is liquid or solid, the capture facility is classified as either wet or dry. At Boryeong Thermal Power Plant, "Kosol 6," a liquid amine-based substance developed by the Korea Electric Power Research Institute, is used. Korea Midland Power explained that Kosol 6 achieves an efficiency of over 90%, meaning it captures more than 90% of the carbon dioxide in the exhaust gas.

Carbon dioxide liquefaction facility installed at Boryeong Thermal Power Plant of Korea Midland Power Co. Photo by Heejong Kang

The exhaust gas from coal-fired power plants contains environmental pollutants such as sulfur oxides and nitrogen oxides. In Korea, strict environmental regulations are enforced, so these pollutants are removed before discharge. Last year, the average concentrations of sulfur oxides and nitrogen oxides emitted from units 7 and 8 at Boryeong were 8.8?14.8 ppm and 6.9?9.2 ppm, respectively, which are below the permissible limit of 40 ppm. The average concentration of emitted dust was 2?2.3 mg/m³, meeting the regulatory limit of 9 mg/m³. By also capturing greenhouse gas carbon dioxide, it is possible to produce clean electricity.

Although carbon dioxide capture technology is a core technology for advancing toward carbon neutrality, there is a major obstacle to its wider application: economic feasibility. Building facilities and operating the capture process for carbon capture involves significant costs, but profitability is still out of reach.

At Boryeong Thermal Power Plant, it is said that 2.3 gigajoules (GJ) of energy are required to capture one ton of carbon dioxide, including for steam production. Boryeong Thermal Power Plant uses some of the steam intended for power generation. The plant captures carbon dioxide using steam that would otherwise be used to generate electricity by turning turbines. In other industrial settings outside of power plants, steam must be produced separately, which incurs additional substantial costs.

Currently, the cost of capturing one ton of carbon dioxide in Korea is known to be around $150. If Boryeong Thermal Power Plant captures 150 tons of carbon dioxide per day, the cost amounts to $22,500 (about 30 million won) per day.

In the United States, under Section 45Q of the Inflation Reduction Act (IRA), part of the carbon capture costs are offset through tax credits, but there are no such support measures in Korea. As a result, Korean companies are limited to demonstrating CCU technology and are hesitant to apply it to industrial processes or move toward commercialization.

Lee Wanhee, Head of the Carbon Neutrality Department at Korea Midland Power, said, "Sales of liquefied carbon dioxide generate only enough profit to cover operating expenses," and added, "For the commercialization of carbon capture technology, continuous policy support is needed, including improving capture efficiency and revising regulations related to finding new applications."