© SSB
Stuttgart has officially launched its first fleet of hydrogen fuel cell buses, marking a decisive step in its long-term plan to eliminate diesel-powered public transport. On April 14, 2025, officials from the city and the Stuttgarter Straßenbahnen AG (SSB) presented the first of ten Mercedes-Benz eCitaro G articulated buses that are now in operation.
The new buses, developed by Daimler Bus, run exclusively on hydrogen using the newly introduced “H2 Mode,” without relying on grid charging. Each vehicle features a 60 kW roof-mounted fuel cell module, six hydrogen tanks, and four NMC3 battery packs totaling 392 kWh, offering a range of up to 360 kilometers.
“A new era of propulsion is beginning for SSB city buses,” said Dr. Frank Nopper, Mayor of Stuttgart and Chairman of the SSB Supervisory Board. “With these state-of-the-art fuel cell articulated buses, Stuttgart and SSB are embarking on a zero-emission future.”
From Setback to Opportunity: Gaisburg Depot Fire Accelerates Transition
The shift to hydrogen technology gained momentum following a 2021 fire at the SSB’s Gaisburg depot. In the aftermath, SSB accelerated its plan to modernize its fleet. Gaisburg now hosts a hydrogen refueling station, currently supplied by trailers, but a pipeline connection is planned.
By 2027, SSB aims to operate only emission-free buses within Stuttgart’s city center and expects to transition the entire network by 2035. A total investment of €31 million is planned, with €1.4 million in state funding and €3.4 million from the city of Stuttgart.
Transport Minister Winfried Hermann stressed the broader impact of the initiative: “The transition to alternative drive systems is crucial for advancing climate protection in transport. Public transport has a clear role model function. The new buses bring clear benefits: cleaner air, less noise, and modern, comfortable vehicles.”
Hydrogen Power Meets Stuttgart’s Terrain Challenges
Stuttgart’s demanding geography, characterized by steep inclines like those on the Weinsteige route, played a central role in the choice of technology. The combination of fuel cells and high-capacity batteries allows the buses to maintain efficient performance even on challenging routes without forcing the fuel cell to operate inefficiently.
Thomas Moser, Technical Director and Spokesperson of the SSB Board, called the transition “one of the biggest changes to our core business since the switch to light rail.”
SSB collaborated closely with Daimler Bus in planning the routes and vehicle specifications. “We must skillfully combine the respective strengths of different drive systems within the fleet,” added Markus Wiedemann, Head of SSB’s Bus Division.
Modern Features Enhance Passenger Experience
Each 18-meter eCitaro G bus can transport up to 124 passengers and includes amenities such as Thermatronic air conditioning, USB sockets, LED lighting, and intelligent eco steering. Safety systems like Sideguard Assist 2, Frontguard Assist, Attention Assist, and a five-camera surveillance system further enhance operational reliability. The buses are also fully accessible, featuring folding ramps and large spaces for wheelchairs and strollers.
