Introduced at the 2008 Detroit Auto Show, the Saturn Flextreme Concept is actually two concept vehicles in one. Co-developed with General Motor's European arm, the same vehicle was shown at the 2007 Frankfort Auto Show wearing Opel badges.

Saturn Flextreme Concept
Saturn Flextreme Concept

Designed to compete in the growing compact crossover segment, Flextreme expands on GM's "E-Flex" technology first seen at the 2007 Chicago Auto Show on Chevrolet's Volt concept.

E-Flex uses an electric motor powered by a lithium-ion battery, supplemented by an auxiliary power source, which can be a gasoline or diesel internal combustion engine or a hydrogen fuel cell. The system is designed to provide up to 40 miles of driving solely on battery power.

Once the battery is depleted, the auxiliary power source kicks in to power the vehicle and recharge the batteries. Flextreme can then be plugged into a household electric outlet overnight to completely recharge the system. The concept uses a relatively small 1.3-liter turbocharged diesel engine as its auxiliary power source.

Saturn Flextreme Concept
Saturn Flextreme Concept

Saturn claims Flextreme has a driving range of 444 miles from a single tank of diesel fuel. According to Saturn, most Americans commute between work and home in less than 40 miles, making it theoretically possible for some drivers to rarely or never engage the diesel engine.

Like GM's other E-Flex concept vehicles (Chevy Volt and Cadillac PROVOQ), production readiness hinges on the advancement of lithium-ion battery technology, needed in order to make the hybrid system practical and affordable. If all goes well, E-Flex vehicles could reach consumers' hands in the early part of the next decade, well before stringent fuel economy regulations go into effect in 2020.