BAE Systems said it has been selected by the Republic of Ireland’s National Transport Authority (NTA) and Alexander Dennis Limited (ADL) to supply up to 600 electric power and propulsion systems for its new fleet of buses in Ireland.

The powertrain is designed so that no mechanical link exists between the diesel engine and the axle. All power comes from the electric motor and power flows in series from the engine to the generator to the traction motor. Source: BAE SystemsThe selection includes an initial order for 100 systems.

The buses will use BAE's Series-ER technology, enabling them to drive on electric power through designated low- and zero-emission zones. The system uses global positioning software to enable the buses to run in full electric mode when they enter the zones, then switch back to conventional diesel power when they exit the zones.

The buses include an onboard generator that reduces the need to provide a separate battery charging infrastructure. The batteries allow the buses to operate on electric power around 35% of the time with the engine off.

Earlier, the San Francisco Municipal Transportation Agency set up zero-emission zones using Series-ER buses equipped with geofencing technology. The nine green zones are located in neighborhoods that are most affected by air pollution.