July 12, 2026. The Société des Transports de l’Agglomération Stéphanoise (STAS) has launched its first Bio-CNG buses on the M5 line in Saint-Étienne, France, which were inaugurated on July 9. Seventeen vehicles run on biomethane produced from organic waste and wastewater in the region, representing an investment of €16 million.
Just weeks after the arrival of its trolleybuses on the M6 line, Saint-Étienne Métropole is opening a second front in the decarbonization of its network. This time, the focus is on a fleet of Bio-CNG buses. The seventeen vehicles—11 standard and 8 articulated—have been in operation since June 17 and replace diesel buses that had reached the end of their service life on one of the network’s main lines.
The M5 line, which connects Saint-Étienne and Rive-de-Gier, carries 9,100 passengers a day, or more than 1.6 million a year, making it a demanding operating environment for a first rollout. The buses are air-conditioned, have an interior rearview mirror instead of exterior mirrors, and are advertised as being 50% quieter than a comparable internal combustion engine bus.
