In a groundbreaking move towards sustainable urban living, South Korea has introduced the world's first 'hydrogen apartment' block in the city of Ulsan. The Yuldong-With-U complex, consisting of 437 households, has successfully transitioned to using hydrogen fuel cells for 100% of their heat and electricity needs. The innovative approach is a result of the Yuldong Combined Heat and Power Plant, which utilizes hydrogen as a byproduct received through a 10 km pipeline from nearby industries. The project has proven to be highly efficient, generating 840MWh of power in June alone, which in traditional utility bills would have cost 150 million won. With three container-sized fuel cells on the complex's rooftop, the plant can produce 1.31 megawatts of electricity from 51 kgs of hydrogen per hour, ensuring a steady supply of electricity for the residents. Apart from electricity, the process also produces heat, which is captured and stored for further use. The heated water, reaching temperatures up to 70 C, is then distributed through pipelines directly into homes for efficient heating. This method of utilizing hydrogen not only reduces environmental impact but also proves to be the most cost-effective option compared to other processes. Fuel cells, which operate similarly to batteries, offer high efficiencies and sustainability benefits, making them an ideal choice for powering urban complexes. The Yuldong-With-U project signifies a major step towards eco-friendly living in urban environments, with plans to further amend regulations to provide residents direct access to cost-effective hydrogen-generated electricity.