Stockholm tests ethanol-fuelled hybrid buses

Sweden’s Scania has started full-scale operational trials with six ethanol-fuelled hybrid buses on the streets of Stockholm.

Run in cooperation with Stockholm Public Transport and Swebus, the trials aim to further improve environmental conditions in the Swedish capital. The buses’ hybrid technology is expected to reduce fuel consumption by 25 percent, while the use of ethanol will cut net carbon dioxide emissions by up to 90 per cent.

During the two-year trial period, the buses will serve one of the more demanding and heavily used lines in Stockholm.

“These operational trials will give us valuable experience of how hybrid technology shapes up in real life, as well as of its environmental effects,” said Göran Hammarberg, head of bus development at Scania. “Long-term, hybrid technology will help us reach even more ambitious environmental objectives for urban traffic.”

The Scania OmniLink buses feature a series hybrid powertrain in which there is no mechanical connection between the combustion engine and the propulsion motor. Electrical power is generated by a diesel engine adapted to run on ethanol. Mechanical energy is converted to electrical energy in a generator.

The six buses are driven by an electrical motor that doubles as a generator when braking. Energy is stored in supercapacitors with considerably longer service life than today’s batteries.

Since 1989, Scania has supplied some 400 ethanol city buses to Stockholm Public Transport.