Ulsan City in South Korea has unveiled the world's first carbon-neutral apartment complex powered by hydrogen instead of city gas for heating. The city's hydrogen fuel cell power plant in Yuldong District generates electricity using hydrogen sourced from the Ulsan Industrial Complex, with excess heat utilized for water and space heating in nearby apartment buildings. This transition has led to a significant reduction in heating costs for residents, with the heating expenses being 70% lower compared to city gas, saving households an average of 10,000 won per month. Ulsan City plans to further expand its hydrogen infrastructure by connecting industrial complex hydrogen pipelines to charging stations and hydrogen trams, fostering a unique approach to hydrogen utilization beyond conventional vehicles. Additionally, the city aims to establish a large-scale hydro electrolytic hydrogen production facility by 2028, promoting clean hydrogen production using surplus electricity from nuclear power plants. This initiative not only promotes sustainability and energy efficiency but also positions Ulsan as a leader in innovative green technologies and urban development.