Korean Utility Plans First Underground Combined Cycle Power Plant

The oldest power plant in South Korea is making way for something so new that no one has even attempted it before. Korea Midland Power Corp. (KOMIPO) announced earlier this year that Seoul Thermal Power Station, built in the 1930s, would be replaced with a new 800-MW two-unit combined cycle power plant—one that will be built entirely underground. Two units of the old plant are still in operation, but will be decommissioned and remodeled into a creative cultural center once the new plant comes online.

The new Seoul Combined Power Plant will be the first underground grid-scale power plant in the world. The plant facilities will be built on a 194-m x 164-m pad at an average depth of 25 m. Excavating the site will require removing 40,000 25-ton truckloads of earth. In addition, the close proximity to the Han River will require thick barrier walls within the pit to prevent water intrusion. At surface level, the site in the Mapo-gu district of central Seoul will become a combined cultural complex for city residents, and will feature an eco-park, sports facilities, performance facilities, a library, and an observatory that will be built by utilizing the power plant stacks.

Engineering and construction, which began earlier this year, is being handled by a consortium of Korean firms Posco Engineering & Construction, Keangnam Enterprises, Sambu Co., and Yooho Development & Construction. The plant, which will also supply district heating to the surrounding area, is expected to be ready by September 2016.

—Thomas W. Overton, JD, gas technology editor (@thomas_overton, @POWERmagazine)