FRANKFURT - General Motors’ E-Flex powertrain will be the key to cutting CO2 emissions, product chief Bob Lutz said at the unveiling of an Opel concept wagon with the powertrain, according to Business Wire.

The Opel Flextreme wagon mates the E-Flex’s electric motor and lithium-ion battery pack to a 1.3-liter diesel engine. The diesel turns a generator for electricity when the battery pack is drained. The battery, which provides a range of 55 kilometers (35 miles), can also be recharged by plugging it into an electric outlet.

GM claims the powertrain in the E-Flex cuts CO2 emissions to 40 grams per kilometer, well under the European Union’s proposed standard of 120 g/km.

The Flextreme is more than just a powertrain showcase. The concept’s sleek design language will influence all future Opel models, said Mark Adams, head of design for GM Europe.

Among the standout items on the Flextreme concept are a panoramic glass roof, rear-hinged doors and small cameras in place of rear-view mirrors to cut down on wind resistance, reported Business Wire.

“This is about showing that you can have a dramatic design statement and high technology go hand in hand,” Adams said. Size wise, the Flextreme fits in between the Opel Astra and Zafira wagons.

GM said a vehicle based on the Flextreme will reach production, but it did not disclose any timing for that move. GM has set a goal of getting the E-Flex powertrain into production by 2010.