Recently, South Korea's largest automaker, Hyundai Motor Company, peeled back the curtain to unveil the latest addition to its sub-brand Blue Drive; the compressed natural gas (CNG) hybrid Blue-City bus. Hyundai's hybrid bus features the automaker's 237-horsepower G-CNG engine, which is connected to a 6-speed automated manual transmission. The Blue-City sports a 60kW electric drive motor and 3.8kWh lithium-polymer battery pack.
The National Renewable Energy Laboratory (NREL), which is part of the US Department of Energy, has been monitoring the performance of three types of buses in New York City for the past year and now has some results to share. They looked at buses powered by conventional diesel drive-trains, compressed natural gas and diesel-hybrids built by DaimlerChrysler. The hybrid buses won out by a huge margin. They had 34 percent better fuel efficiency than the diesels and 60-120 percent better than the CNG