BAE Systems says Massachusetts Bay Transportation Authority (MBTA) has ordered 194 electric-hybrid buses using its Series-ER extended range propulsion system.

Half BAE’s 10,000 system deliveries were made in the past three years.

The company is delivering its Series-ER system with a higher capacity battery to help Massachusetts reduce emissions and noise pollution on its transit bus routes. The Series-ER system – which uses electric motors instead of diesel engines to power the buses – builds on the company’s technology, which it claims is saving more than 22m gallons of fuel and 250,000 tons of CO2 each year across the globe.

The battery is recharged by both an on-board generator set, using a down-sized internal combustion engine and by regenerative energy produced when the bus slows to a stop. By moving to a Series-ER system, a fleet can operate a portion of the day electrically with the engine off, reducing maintenance, idling, fuel use and emissions.

Cities such as Nashville are using Series-ER technology to drive battery-electric power near hospitals, schools and in the downtown tourist area, while Boston plans to use the technology for its tunnels.

“Our new technology provides Massachusetts with a practical electric-hybrid solution,” said BAE Systems Power and Propulsion Solutions VP and general manager, Steve Trichka.

“This system provides clean electric operation that can be rapidly scaled now to help Massachusetts reap the benefits seen in thousands of buses worldwide.”