The buses, which began service in 2011, are being trialled by the CHIC (Clean Hydrogen in European Cities) project.
The fuel cell buses travel daily like conventional buses, and have also been used as shuttle buses at different events such as the World Economic Forum in Davos (Switzerland).
CHIC is currently assessing the possibility of continuing the operation of the buses after the official end of the project in December 2016.
The CHIC project is co-funded by the Fuel Cells and Hydrogen Joint Undertaking (FCH JU), a public-private partnership supporting research, technological development and demonstration activities in fuel cell and hydrogen energy technologies in Europe.
The three members of the FCH JU are the European Commission, fuel cell and hydrogen industries represented by the NEW Industry Grouping and the research community represented by Research Grouping N.ERGHY.
For more information, visit chic-project.eu.