Construction to build the world\'s first-ever underground thermal power plant in an urban area kicked off Friday in Seoul, developers said. The project entails building two underground generators directly under two thermal generators currently in operation in Mapo, central Seoul, according to Korea Midland Power Co., Ltd. The construction is expected to cost a little over 1 trillion won (US$931 million), and be completed by September 2016. As the only power plant in capital Seoul, the new and expanded Mapo facility will also supply up to 9.8 percent of Seoul\'s entire power consumption. It will also provide heat from its generators to heat nearly 100,000 homes in the Mapo and Yeouio areas, the company said