Barcelona Electric Bus Opportunity Charging

Urban bus operators share the challenge to run city buses in an especially sensible environment, where NOx, PM and HC emissions same as noise pollution have high effects on the population’s health and well-being. For these reasons, electric buses become an alternative to replace ICE (internal combustion engines) from this specific use.
A bus in an urban route usually requires 16 h of operation because it is used for two shifts of 8 hours in a row. The actual state of art in the battery market, allows the possibility to mount up to 400Kwh on board, with a weight of 4 tons, but this energy is not enough to assure 16 h of operation during summer time (with air conditioning). Hence, the bus must be replaced before finishing its daily service. In this case, the operator needs two buses for a daylong service of 2 shifts. Therefore, this solution is not viable.
To solve this problem, TMB has implemented an Opportunity Charging strategy consisting in a special kind of batteries (LTO) that allow frequent charging of smaller amounts every half route (12/15 km) in a very short time (3 minutes). This guarantees the operationality of the bus during the full 16 h of service.
Considering the infrastructure, one fast charger is placed at each side of the line where the bus charges the necessary energy to arrive to the other side. The bus has however enough autonomy to run 60 km without charging. This strategy allows the vehicle to run more than 24 hours without returning to the depot.