Croatia – City of Zagreb & REGEA
Zagreb’s Shared Vision for Hydrogen Mobility
The City of Zagreb and REGEA developed a vision of hydrogen-powered urban transport, set targets for bus and refuelling deployment, and mediated conflicts between municipal budget constraints and national infrastructure priorities.
Overview
The City of Zagreb, the capital of Croatia and the country’s main economic and innovation hub, is positioning itself as a national leader in the development of hydrogen-based clean mobility. It has long been committed to improve the sustainability and efficiency of its public transport system. In line with the City’s broader decarburization goals and European Union climate targets, Zagrebački električni tramvaj (ZET), the city’s public transport company, launched a pilot project to test a hydrogen-powered bus within Zagreb’s public transport network. This initiative formed part of the Green Hydra project under the JIVE 2 program, which promotes the introduction of hydrogen technologies into public transport systems across Europe.
The pilot’s main objective was to evaluate the technical performance, operational feasibility, and environmental benefits of hydrogen fuel-cell buses under real urban conditions. Through the Zagreb’s Shared Vision for Hydrogen Mobility initiative, the City aims to integrate renewable and low-carbon hydrogen into public and commercial transport systems, complementing Croatia’s Hydrogen Strategy 2050 and aligning with the EU’s decarbonization goals.
Implementation and Key Activities
In December 2022, the pilot was implemented in close cooperation between the City of Zagreb, ZET, the Croatian Hydrogen Association, and the Croatian Hydrocarbon Agency. The hydrogen bus, equipped with a modern fuel-cell system, was tested during a Central and Eastern European road-show that included several cities, with Zagreb serving as one of the main testing locations. The vehicle was operated in real driving conditions, including city routes featuring hilly terrain and sub-zero winter temperatures, providing valuable insights into its performance in demanding environments.
Although the bus did not carry passengers during this particular trial - due to administrative and safety restrictions - it was run as part of the regular operational framework to collect accurate technical data. The pilot involved continuous monitoring of fuel consumption, driving range, maintenance requirements, and energy efficiency.
The lack of hydrogen refueling infrastructure emerged as the most pressing challenge. Many countries in the region still have few or no refueling stations, and there is a general shortage of operators willing to invest in the construction of new facilities. The economic viability was another major concern. The high purchase costs of buses and hydrogen refueling stations make it challenging to build a strong business case. Despite these challenges, the roadshow proved highly successful in raising awareness and generating enthusiasm. Demonstration drives allowed citizens, operators, and city officials to experience hydrogen buses firsthand, leading to overwhelmingly positive feedback.
Results and Policy Impact
The hydrogen bus trial yielded positive operational results and significant policy insights.
Beside Croatia, the course trial included Slovenia, Czech Republic, Slovakia and Hungary, covering approximately 1,641 kilometers, consuming around 125 kilograms of hydrogen, with an average fuel consumption of 7.6 kg per 100 km. The vehicle performed well even in low temperatures and on challenging terrain, proving the reliability and resilience of hydrogen fuel-cell technology under Zagreb’s climatic and topographical conditions.
The initiative has become a valuable source of information, inspiring other urban areas and counties to consider hydrogen in their sustainable mobility plans. By combining local mobility needs with European decarbonization goals, Zagreb is laying the foundation for a scalable, sustainable hydrogen ecosystem that contributes both to Croatia’s energy transition and to the EU’s broader climate-neutrality agenda.
Transferability and Lessons Learned
Zagreb’s hydrogen bus pilot offers a transferable model for other European and regional cities exploring zero-emission mobility solutions. The project demonstrates that even without an established hydrogen infrastructure, it is possible to carry out meaningful pilots using mobile refueling systems and short-term demonstrations.
Lessons learned include:
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Access to low-cost, renewable energy will be essential for producing hydrogen in a cost-effective manner.,
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As with all innovative technologies, hydrogen fuel buses require comprehensive training compared with diesel buses,
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Hydrogen refueling stations must be planned strategically, they should be scalable, located close to depots, and integrated into normal operational routines,
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Larger fleets will lower capital and hydrogen costs, enhance maintenance efficiency, and support long-term market development.
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Several elements were critical to the success of the hydrogen bus pilot in Zagreb:
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Strong partnerships and institutional coordination between ZET, the City of Zagreb, and national energy and hydrogen associations,
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Real-world operational testing, providing credible data and direct experience with hydrogen technology,
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Visibility and public outreach, achieved through media coverage and stakeholder workshops, which increased awareness of hydrogen as a viable clean public transport option,
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Technical reliability demonstrated by the bus’s performance in cold, hilly conditions, showing that hydrogen can complement battery-electric solutions
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