The idea behind this concept, which will debut at the Geneva Motor Show, is to show how the Volt’s extended-range electric vehicle drivetrain can be used in a larger vehicle, in this case a mid-size five-door hatchback. So far, every vehicle shown by General Motors with an ER-EV drivetrain, including the Volt, Ampera and Cadillac Converj concept, has been compact in size.

By paying attention to aerodynamics, the Flextreme GT/E still achieves a low 0.22 coefficient of drag despite its bigger dimensions and large 21-inch wheels. It even employs active aerodynamics in the rear where panels extend out from the air extraction slots behind the rear wheels at speeds above 50 km/h (31 miles per hour). Opel also used carbon composite panels for the body and aluminum for the vehicle structure to keep weight down.

Powered by an electric motor producing 120 kW and 273 pound-feet of torque, the Flextreme GT/E is augmented by a 1.4-liter four-cylinder gas engine/generator. It will travel 37 miles on battery power alone before the generator kicks in to keep supplying electricity to the motor, at which point its range extends to 311 miles. CO2 emissions are kept below 40 g/km and Opel pegs fuel consumption at 1.6 liters/100 km (converted straight that’s about 147 mpg).