Cummins has developed a modular engine block with interchangeable cylinder heads and injection systems to be powered by a multiple of clean fuels namely hydrogen, biogas, diesel and HVO (biodiesel).

The total number of alternative drivelines in city buses in European Union 27 countries plus the UK, Norway (NO), Iceland (ICE) and Switzerland totalled 8,911 units accounting for 59.2% of total city bus registrations in 2021 of 14,990 units, according to market analysis by Wim Chatrou of Chatrou CME Solutions of The Netherlands.

While hydrogen still has less of a market share than many other alternative fuels, it has some compelling advantages as a fuel: It offers zero emissions, especially for heavy-duty vehicles that require fast fill times and a lot of on board energy storage, stated Erik Bigelow, Center for Transportation and the Environment.