The Denver Regional Transportation District has awarded UQM Technologies a contract to retrofit generators and motor controllers for 18 hybrid electric mall shuttle buses. A 35 kW UQM generator and two UQM power electronic motor controllers will be installed to control the electric propulsion motors in each bus. The other 18 buses in Denver’s mall shuttle fleet have already been retrofitted.

The hybrid electric buses are powered by a compressed natural gas-fueled 2.5 liter Ford industrial engine that operates at 2,200 rpms and will turn the UQM generator to produce electricity to recharge the bank of batteries that power the shuttle. The UQMmotor controllers feature regenerative braking.