The Yuldong-With-U apartment complex in Ulsan, South Korea, has introduced the world's first 'hydrogen apartment' complex, a pioneering move in sustainable urban living. This innovative building harnesses heat and electricity from hydrogen fuel cells, potentially leading to significant energy cost savings. The complex, comprising 437 apartment units, relies on the Yuldong Combined Heat and Power Plant located nearby to efficiently produce electricity and heat with minimal environmental impact. By utilizing hydrogen pipelined from various industrial activities to the plant, it achieves cost-effectiveness in energy production. The rooftop of the complex houses three container-sized fuel cells that generate 1.32 MW of electricity from hydrogen per hour, providing ample power for the apartments while storing heat for heating purposes. The official operation of the complex on June 1 marked the successful production of around 840 MW of electricity, valued at approximately US$109,000. This initiative highlights the growing importance of hydrogen as an alternative energy source, setting a new standard for sustainable urban living and showcasing the possibilities of carbon-neutral housing.