Hydrogen buses: an alternative with tradition

The MAN Group has been researching hydrogen drives for decades. The MAN Engines business unit is building on this knowledge and is therefore now ideally positioned to quickly bring this sustainable technology into series production.

First hydrogen-powered bus from MAN in 1996 — A pioneer: 60,000 passengers travelled on this MAN hydrogen bus in Erlangen in 1996.

MAN Truck & Bus exhibited the first hydrogen-powered bus at the Hannover Messe trade fair in 1996. The SL 202 city bus was powered by a natural gas engine that had been modified for hydrogen operation. However, it could also be run on conventional petrol. Following the Hannover Messe trade fair, the vehicle completed a nine-month trial phase in Erlangen, during which it covered 13,000 kilometres and transported 60,000 passengers. In 1997, the bus finally made its way to Munich where it was used successfully in regular service.

This example shows that the MAN Group has a long tradition of developing and testing hydrogen drives. The first hydrogen bus was followed by three articulated buses for Munich Airport in 1998, which were used until 2008, and another 14 hydrogen-powered buses between 2006 and 2009. Alongside its early and most recent experience with commercial vehicles, the commercial vehicle manufacturer MAN Truck & Bus is now also developing and testing the hydrogen engine in a wide range of applications on and off the road, as well as on water. “In some cases, our colleagues’ knowledge from the 1990s and early 2000s has been incorporated directly into these new developments,” reports Christian Gruber, Senior Expert New Energy for Alternative Drives at MAN, who has been involved in all hydrogen projects almost from the outset. “The success was thanks to the close and intensive cooperation between colleagues from the complete vehicle, powertrain and external engine business sectors. This allowed a hydrogen engine of the latest generation to quickly be put into operation and integrated into the vehicle technology of a semitrailer combination for the first time.”

The MAN Engines business unit, which develops engines for external customer applications, benefits from the experience of developers from the truck and bus sector, as it does in the case of conventional combustion engines. Combined with expertise in the design of drives in special applications, this results in the creation of highly efficient drives for applications in a wide variety of fields. The hydrogen combustion engine is also of interest here due to its robustness, simple structure and high performance. It is particularly well suited for heavy-duty applications, special vehicles, trains on non-electrified routes as well as for diggers and cranes. Use in cogeneration units is also sensible if the generated heat can be used in addition to the electricity.

MAN hydrogen buses at Munich Airport — Clean energy: three hydrogen-powered articulated buses transported passengers at Munich Airport in 1998.

Growing customer interest in hydrogen drives

The MAN Engines business unit is seeing growing interest in climate-friendly drive technology. “It started a few years ago,” recalls Werner Kübler, Head of Development. “More and more customers had been asking about how high the proportion of hydrogen could be for our gas engines. We then began carrying out corresponding tests at our test stations.” Enquiries for dual-fuel engines that can be operated with diesel and hydrogen were streaming in, particularly from the marine sector. MAN Engines now offers dual-fuel engines for ships, and the gas engines are approved for the addition of hydrogen.

Like Gruber, Kübler also predicts promising fields of application for the hydrogen engine. “It is suitable, for example, for the reconversion of green hydrogen, but I also think there are interesting possible applications beyond this.” At present, the constraint is not related to the technology, but rather to the availability and current price of hydrogen. Nevertheless, MAN Engines is already preparing for rising demand and is developing, among other things, a powerful V8 hydrogen engine. During this process the engineers can draw on the knowledge of their colleagues at MAN Truck & Bus, so they do not have to develop everything from scratch. “As soon as our customers show interest, we can flip the switch and offer a well-engineered product,” says Kübler. This would add another sustainable drive to the MAN Engines product range.