Study Insights
As the world races toward net-zero carbon emissions by 2050, South Korea has placed hydrogen mobility at the forefront of its green energy revolution. With ambitious targets under the National Hydrogen Economy Roadmap, the nation is heavily investing in clean transport—particularly hydrogen-powered public transit—to reduce urban pollution and fossil fuel dependence.
One city stands out: Ulsan, an industrial powerhouse transitioning toward sustainability. Its pioneering hydrogen tram and bus projects offer a compelling blueprint not only for Korea but for global cities aiming for zero-emission transit. This case study delves into the technological, environmental, and policy dimensions of Ulsan’s hydrogen mobility journey.
Hydrogen Public Transport in South Korea: A National Context
South Korea’s Hydrogen Economy Roadmap
Hydrogen is a key pillar of South Korea’s 2050 carbon neutrality pledge, backed by robust investments in infrastructure and mobility. The government’s 3UP strategy—Scale-Up, Build-Up, Level-Up—targets clean hydrogen deployment in transport and industrial sectors. By 2030, the plan envisions tens of thousands of hydrogen vehicles and expanded refueling infrastructure.
Hydrogen Buses in South Korea
Since 2019, the Hyundai Elec City FCEV bus has been operational, and by late 2024, cumulative sales exceeded 1,000 units. In the southeastern megacity cluster of Busan–Ulsan–South Gyeongsang, trial services began in 2022 under a Hyundai-led initiative, with an ambition to deploy over 600 hydrogen fuel cell buses by 2025. Hydrogen buses offer fast refueling (~10–20 minutes) and long ranges (up to 500 km), addressing operational efficiency.
South Korea’s Hydrogen Trains and Trams
The government, in collaboration with Hyundai Rotem, is developing hydrogen fuel cell trams, merging zero-emission transport with catenary-free flexibility. A prototype was unveiled in 2021, followed by a commercial model under development by 2024 through a Ministry-led R&D project.
Ulsan as South Korea’s Hydrogen Capital
Why Ulsan? Industrial Strength Meets Clean Energy Vision
Ulsan has long been recognized as the industrial powerhouse of South Korea, home to some of the nation’s largest shipbuilding yards, petrochemical complexes, and automotive manufacturing plants. This heavy industry legacy created an advanced infrastructure base—pipelines, refineries, and logistics systems—that now serves as a natural springboard for hydrogen innovation. Rather than viewing its fossil fuel–intensive history as a limitation, Ulsan has leveraged it into an opportunity for transformation.
Designated as one of South Korea’s first Hydrogen Pilot Cities in 2019, Ulsan has committed itself to becoming a global leader in hydrogen-based clean mobility. The city invested approximately KRW 250 billion (about USD 200 million) in 2018 to establish hydrogen as a core energy vector. This ambitious initiative included not only expanding refueling stations and pipeline networks but also integrating hydrogen fuel cells across multiple sectors, such as public transport, industrial machinery, and even residential energy systems.
Today, Ulsan boasts one of the most comprehensive hydrogen ecosystems in the world. The city is pioneering hydrogen-powered trams, buses, and logistics vehicles, while also developing large-scale hydrogen production and storage facilities. This combination of industrial expertise, government backing, and corporate leadership positions Ulsan as the “Hydrogen Capital of South Korea”—a role that has global implications for the clean energy transition.
Government-Industry Collaboration in Ulsan
The success of Ulsan’s hydrogen strategy lies in its deeply collaborative model, where government policies align seamlessly with private-sector innovation. Multiple stakeholders across industries and research institutions have joined forces to accelerate hydrogen mobility projects.
- Hyundai Rotem, a key player in rail transport manufacturing, has spearheaded the design and development of hydrogen-powered trams, marking the first of their kind worldwide.
- The Korea Railroad Research Institute (KRRI) and the Korea Automotive Technology Institute (KATECH) have contributed cutting-edge research on hydrogen fuel cells, storage systems, and vehicle integration.
- Ulsan Technopark, a regional innovation hub, plays a vital role in bridging academia, government, and industry by providing R&D support, testing facilities, and commercialization pathways.
At the policy level, both the national government and the Ulsan Metropolitan Government co-invest in infrastructure projects, share R&D costs, and provide regulatory support to fast-track hydrogen deployment. This model ensures that the burden of high initial investment in hydrogen technology is shared, thereby reducing risks for private companies and encouraging continuous innovation.
Such public–private synergy has transformed Ulsan from a traditional industrial hub into a living laboratory for hydrogen solutions. The city’s collaborative ecosystem is often cited as a model for how governments and industries can jointly build the foundations of a sustainable, hydrogen-driven economy.
Hydrogen Tram Networks in Ulsan
World’s First Hydrogen Tram Project
In November 2023, Hyundai Rotem’s hydrogen-electric tram successfully completed test runs: a 35-meter, five-carriage tram ran a 4 km route at a top speed of 40 km/h and a range of 150–200 km per charge. Demonstration runs covered more than 5,000 km by early 2024, with 3,000 citizens and experts attending promotional ride-alongs.
Construction is slated to begin in 2026, with the first line—a wireless hydrogen tram line featuring 15 stations over approximately 10.9 km from Taehwagang Station to Sinbok Rotary—expected to launch in 2028, serving around 24,000 passengers daily.
Infrastructure and Hydrogen Refueling Stations
Ulsan is building depots and hydrogen refueling hubs to support tram operations. As part of Ulsan Green Hydrogen Town, the city has laid 188 km of underground pipelines channeling industrial byproduct hydrogen to charging stations and residential heating grids.
Economic and Environmental Benefits
- Emission reductions: The tram emits only water vapor, cutting greenhouse gases and local pollutants.
- Tourism and branding: Positioned as a flagship attraction tied to the upcoming International Garden Show and enhanced access to cultural sites.
- Green jobs and supply chain growth through construction, operation, and hydrogen logistics.
Hydrogen Bus Networks in Ulsan
Deployment of Hydrogen-Powered Buses
Ulsan has taken a bold step in advancing hydrogen-powered public transportation, positioning itself as a testbed for clean mobility solutions. In 2022, the city, together with neighboring Busan and South Gyeongsang Province (collectively known as the Bu-Ul-Gyeong region), launched hydrogen bus trials spanning 3,500 kilometers across five dedicated routes. These demonstrations were not simply symbolic but part of a structured program to evaluate key aspects of hydrogen bus adoption—including vehicle performance, passenger safety, comfort, and operational cost-effectiveness under real-world conditions.
The early trials provided valuable insights: hydrogen buses proved capable of maintaining consistent power delivery on both flat and hilly terrains, handling Ulsan’s mixed industrial–urban landscape with ease. This data has reinforced the viability of hydrogen as a scalable alternative to diesel buses, particularly for regions with long-distance commuting patterns and high passenger volumes.
Refueling Infrastructure and Efficiency
One of the major advantages that hydrogen buses bring over battery-electric buses is their rapid refueling capability. Whereas charging an electric bus can take several hours depending on grid conditions, hydrogen buses can be refueled in just 10–20 minutes, similar to the turnaround time for conventional diesel refueling. This makes them exceptionally well-suited for high-frequency public transport systems, where downtime directly translates to reduced service efficiency.
Hyundai Motor Company, headquartered in nearby Seoul but with extensive R&D presence in Ulsan, has equipped these buses with state-of-the-art hydrogen fuel cells, enabling ranges of up to 500 kilometers on a single fill. This range not only reduces the frequency of refueling stops but also ensures reliability on long intercity routes.
To support this network, Ulsan is steadily expanding its hydrogen refueling infrastructure, integrating it with the existing industrial pipeline systems that already transport hydrogen as a by-product of petrochemical processes. This approach lowers costs while ensuring a more sustainable supply chain for the city’s hydrogen transport fleet.
Social and Economic Impact
The deployment of hydrogen buses in Ulsan is not just a technological upgrade—it represents a transformative shift for society and the local economy.
- Cleaner Air and Healthier Communities: Diesel buses are among the largest contributors to particulate matter (PM2.5) and nitrogen oxide (NOx) emissions, both of which are directly linked to respiratory illnesses. By replacing diesel with hydrogen, Ulsan reduces urban air pollution, delivering tangible health benefits to its residents.
- Boosting the Hydrogen Innovation Hub: The bus project strengthens Ulsan’s role as a hydrogen ecosystem hub, spanning research, manufacturing, infrastructure, and end-use applications. It also complements South Korea’s national strategy to achieve net-zero emissions by 2050.
- Economic Spillover Effects: The hydrogen bus network stimulates demand across multiple industries—from fuel cell development and storage technologies to station construction and maintenance services. This creates new jobs, attracts R&D investments, and fosters Ulsan’s image as a global pioneer in sustainable mobility.
By integrating hydrogen buses into daily transport, Ulsan is demonstrating that clean energy mobility can be both practical and scalable—a message that resonates not just in South Korea but worldwide.
Challenges and Opportunities for Hydrogen Transport in Ulsan
Technical Challenges
- High infrastructure costs for hydrogen production, storage, and refueling stations.
- Logistical complexity in hydrogen distribution networks.
- Efficiency concerns, as hydrogen conversion remains less efficient than batteries.
Policy and Market Challenges
- Hydrogen must compete with electric vehicles gaining traction.
- Sustained subsidies, clear regulation, and supply chain support are critical for scalability.
Opportunities Ahead
- Positioning Ulsan as a hydrogen export center, especially in mobility tech.
- Serving as a model Hydrogen City, attracting international delegations for benchmarking.
Global Comparisons: How Ulsan Stacks Up
Hydrogen Transport in Europe
Cities in Germany, France, and the UK have piloted hydrogen buses and trams with varied success. Ulsan’s tram stands out as one of the first full-scale urban hydrogen rail systems.
Hydrogen Mobility in Japan and China
Japan and China are progressing rapidly. Ulsan’s model showcases competitive policy alignment and industrial partnerships that other Asian leaders are watching closely.
What the World Can Learn from Ulsan
- Effective government–industry collaboration.
- Emphasis on integrated hydrogen infrastructure, from generation to end-use.
- Use of pilot demonstrations to build public trust and gather performance data.
Future Outlook for Hydrogen Public Transport in South Korea
Scaling Hydrogen Buses and Trams Nationwide
Following Ulsan’s success, cities like Daejeon are launching hydrogen trams (Metro Line 2 by 2028). Nationwide deployment of 30,000 commercial hydrogen vehicles by 2030 is the broader goal.
Integration with Renewable Hydrogen Production
Expansion of offshore wind and solar projects will enable green hydrogen production, reducing reliance on imported fossil-derived sources—key for sustainable scaling.
Hydrogen Cities of the Future
Ulsan—through tram, bus, power, heating, and residential pilot—becomes a living laboratory for hydrogen-based smart cities of tomorrow.
FAQs on Hydrogen Tram & Bus Networks in South Korea
What makes hydrogen buses and trams better than electric ones?
Hydrogen vehicles offer fast refueling (10–20 minutes) and longer driving ranges (~500 km) without the need for extensive catenary wire systems. They reduce reliance on heavy batteries and emit only water vapor—crucial for large-scale public transit operations.
How many hydrogen buses are currently running in Ulsan?
As of 2025, trial operations are underway with hydrogen buses deployed regionally across Bu-Ul-Gyeong, with more than 600 buses planned by 2025.
Is hydrogen fuel safe for public transport?
Yes. Hydrogen systems in Ulsan include extensive safety validation—covering fuel cells, storage devices, and operational protocols—before the tram line opens.
How does South Korea produce hydrogen for buses and trams?
Ulsan repurposes byproduct hydrogen from its industrial complexes, delivered via an advanced network of pipelines. Investments also support renewable hydrogen scale-up.
Will hydrogen trams and buses replace diesel entirely in South Korea?
They are intended to augment and gradually replace diesel fleets, particularly on high-ridership corridors. National goals foresee hydrogen mobility as a leading alternative, but full replacement will take years with scaling infrastructure being key.
What is the cost of building hydrogen fueling stations in Ulsan?
Exact station costs are not publicly detailed, but the overall hydrogen city infrastructure—including pipelines, power systems, and charging stations—has seen investments in the hundreds of billions of won.
How does Ulsan’s hydrogen project compare with Japan’s Tokyo fuel cell buses?
While Tokyo runs hydrogen buses, Ulsan’s integrated tram system, pipeline delivery, and hydrogen-powered housing showcase a more systemic, city-wide approach to hydrogen integration.
Can hydrogen mobility create new jobs in South Korea?
Absolutely. Infrastructure projects, R&D ventures, and operations create green-sector employment and strengthen South Korea’s global leadership in hydrogen technologies.
Conclusion: Ulsan as a Blueprint for Hydrogen-Powered Public Transport
Ulsan’s hydrogen tram and bus initiatives represent a pioneering synthesis of industrial capacity, public policy, and environmental vision. Together, they illustrate how carefully designed pilot projects can evolve into scalable solutions that reshape urban mobility. The city’s experience demonstrates the interdependence of infrastructure, technology, and policy in driving systemic change, while also underscoring the potential of zero-emission transport to reduce air pollution and foster more sustainable urban systems.
As Ulsan moves toward full-scale operations between 2027 and 2029, it stands as a living case study for cities worldwide that are seeking effective pathways toward clean and resilient transport alternatives. For students, professionals, and researchers alike, Ulsan offers a wealth of insights—encouraging us to stay engaged, learn from its data and design, and apply these frameworks globally to accelerate the transition to sustainable mobility.
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South Korea’s Hydrogen Tram & Bus Networks
