The world’s first fast-charged hybrid bus, the "Arctic Whisper" has been unveiled in Sweden.
The bus, the Bůsbaar, is said to combine the no-emission benefits of an electric bus with the reliability of a diesel bus. The Bůsbaar charging station provided by Spanish firm Opbrid SL will be located at one end of the bus route that will fast charge the bus for a few minutes at the end of each trip. This will extend the all-electric range of the hybrid bus from two hours to 18 hours. And, since this is a serial hybrid bus with a backup diesel generator, the bus can continue running on bio-diesel in case of brown-outs, traffic jams, or very cold weather.
The city of Umeå, in the far north of Sweden, where the bus was unveiled, has found a solution to electrifying its bus system. Umeå is a university city with many daily bus riders but it’s very cold weather in winter. It has access to large amounts of clean electricity from hydro and wind power. Both diesel fuel and bio-fuels such as ethanol are very expensive in Sweden so converting the city buses to electricity makes good economic sense, and it supports the city’s goal of reducing CO2, noise, and air pollution.
The city’s vision is to fill Umeå’s streets with a number of these fast-charged hybrid buses by 2014, the year that Umeå will be the Cultural Capital of Europe. Since there are no gears or differential, the wheel motors make no perceptible noise.
The e-Traction – an energy focused transport firm – converted Volvo 7700 is a “battery dominant” hybrid bus. This means that it has the ability to run on battery only, with the diesel generator turned completely off. The Arctic Whisper has 100kWh of Valence Li-Ion batteries, typically enough for 1-3 hours of fully electric operation due to the high efficiency of the e-Traction wheel motors. With the addition of the Opbrid Bůsbaar fast charging station, the all-electric operation can be extended to 18 hours.
At the end of the route, the driver pulls up underneath the Opbrid Bůsbaar charging station, and the tram-like pantographs on the bus roof quickly raise up to contact the Bůsbaar. The charging process is completely automatic, with the driver never having to leave the bus. When the batteries are charged, the driver continues on as normal. The batteries are fully charged at night, with the Bůsbaar providing the additional electricity needed for a full day of electric driving.
One of the biggest advantages this system has over other electric bus systems is the backup on-board diesel generator. For example, if there is a power shortage or traffic jam, the bus can switch over automatically to using the backup generator and continue running on bio-diesel indefinitely. This additional source of power gives the system the reliability and confidence of diesel in all weather, traffic, and operating conditions.
Testing of the first bus and charging station has begun and will continue through the spring and summer of 2011, with a second bus arriving soon.
