The Lotte World Tower, at 123 stories, is hard to miss as it sits at the hub of downtown Seoul. At more than a dozen years in the making and another seven in construction, the building officially celebrated its opening four years ago as the tallest building in Korea and the fifth tallest in the world.

Perhaps even more impressive than its towering height is what’s buried six floors beneath the street level: a 20,000-square-foot energy center that is the heart of the structure. The center manages energy from hydrothermal sources, geothermal heating and cooling, heat-insulation glass, solar generations, wind power generators, water recycling facilities (both heavy water and rainwater), and waste heat recovery systems. Taken together, these produce more than 12 percent of the energy needed to operate the massive building. 

In March, a host of dignitaries visited the Tower to recognize the accomplishments of the building towards Korea’s goal of a carbon-neutral nation by 2050. The attendees included Kim Sung-hwan, chairman of the 2050 Carbon Neutrality Committee, and Park Jae-hyun, president of Korea Water Resources Corp., and 10 lawmakers all gathered to see and celebrate Korea’s largest hydrothermal energy facility. 

Employing state-of-the-art technologies, the hydrothermal portion of the Towe’s energy center utilizes the difference in temperatures between the nearby Han River and the atmosphere to harvest emissions-free energy. By leveraging this natural differential—the temperature of the river water is lower than that of the atmosphere in the summer and higher than in the winter—the energy center reduces greenhouse gas emissions year-round. 

It takes in more than 50,000 tons of water every day, and from that supplies 3,000 refrigeration tons accounting for 10 percent of the energy used for cooling and heating the building. It reduces energy consumption by 36 percent and cuts CO2 emissions by 38 percent over other buildings in the nation. In addition, the generation of hydrothermal energy does not require a cooling tower on top of the building. 

As a result of its incorporation of clean and renewable energy solutions into the Tower, it received LEED (Leadership in Energy and Environmental Design) certification from the U.S. Green Building Council in 2017.