The 7700 Hybrid features a parallel hybrid system with the Volvo MD5 diesel engine and Integrated Starter Alternator Motor (I-SAM). The 4-cylinder, 4-stroke turbocharged and intercooled in-line diesel engine delivers 158 kW (212 hp) of power at 2,200 rpm and 800 Nm (590 lb-ft) of torque at 1,200 to 1,700 rpm. Continuous output from the I-SAM motor is 70 kW (94 hp), with 120 kW (161 hp) peak; continuous torque is 400 Nm (295 lb-ft), with 800 Nm peak. A 600V, 4.8 kWh Li-ion battery pack is roof-mounted and water-cooled. (Earlier post.)

We reduce energy consumption per passenger by 50-75%, compared with using an automobile. With such major environmental gains and such large savings in fuel costs, we are convinced that hybrid buses will become extremely attractive and a difficult-to-beat alternative for personal transportation within a few years.

—Edward Jobson, Environmental Director at Volvo Buses

Volvo expects to start series production of hybrid buses at the beginning of 2010. The company has already received its first orders for the bus, including customers in Luxemburg and Switzerland. The field tests now starting in Göteborg are intended for making the final fine adjustments. In the near future, Volvo Buses will also start field tests with the first of six hybrid double-decker buses in London.