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Electric and hybrid solutions

Completely electrifying bus power and propulsion in a hybrid system

Series-E & ER

Transit bus systems around the globe are driving into the future with BAE Systems’ advanced Series-E & ER electric hybrid bus propulsion systems.
Our Series-E & ER smart electric hybrid propulsion systems power your buses completely electrically, and even operate in zero emissions mode. That gives transit systems a healthy edge in achieving energy efficiency and clean air goals.

Over 10,000 of our electric hybrid bus systems now operate around the globe, providing power for both electric bus accessories and electric propulsion. BAE Systems offers two electric hybrid solutions — the Series-E and the Series-ER – to provide zero emission operations where your transit system needs them the most. Both of these systems operate on all electric power. All of the hybrid electric bus accessories are powered with our auxiliary power electronics. The electric motors drive and associated power electronics are designed for full motive power. The only difference is the energy storage systems.

The Series-E system

With our smart Series-E drivetrain technology in your buses, all of your bus accessories – air conditioning, power steering, air compressors, etc. – can be powered by our electric system, and our stop/start function can be used to decrease engine idling at stops. Furthermore, the combustion engine that keeps the batteries charged can be shut-off for short distances – in and around a bus depot or hotel stop, for example – to eliminate emissions and reduce noise.

The Series-ER system

For more "engine-off" electric bus time, you want the Series-ER. Its higher capacity energy storage system allows drivers to operate the bus up to 35% of the time with the engine off, increasing low and zero emission travel options. Recently, Nashville’s WeGo Public Transit set up zero-emission zones using Series-ER paired with geofencing technology. They use Series-ER to provide zero emission zones in their high traffic downtown area, and near hospitals and schools.

Another advantage is that Series-ER can also be implemented without high infrastructure costs. This system has an onboard generator, so Nashville – and your city – can operate electric drive buses without needing to install charging infrastructure and without scheduling times for buses to stop and recharge. With Series-ER installed, once the bus drives out of the geofenced area, it will automatically switch back into electric-hybrid mode. Click here to see a video on how Nashville's WeGo Public Transit describes the Series-ER.

Complete Integration & Support

BAE Systems provides our customers with the most comprehensive power and propulsion systems integration and support in the industry. While others often just ship their system parts to prime bus manufacturers to install, we've sent a certified Application Engineer along with our cutting edge power systems to make sure they are integrated properly from day one, including on-site technical advice and thorough training. Then we back that work with our Flexible Service Plan – customized to fit the customer's business model – including a coordinated spares management program.


Learn more. Visit our electric hybrid bus, electric bus, hydrogen fuel cell electric, and other transit bus power system pages below. Download our Advancing Electric Solutions brochure. Or contact our electric and hybrid solutions director of business development today to arrange a meeting.

Electric and hybrid solutions

See Product Family