The Opel Flextreme is a diesel plug-in hybrid concept small family hatchback created by Opel in 2008. The Opel Flextreme shares the same GM E-Flex platform as the Chevrolet Volt (front engine, four door).

It is based on the same GM E-Flex series hybrid platform used in the Chevrolet Volt,^[1] but using a diesel rather than gasoline engine.^[2] It can travel 55 kilometres (34 mi) on its lithium-ion battery before a small diesel engine starts charging the battery.

The Opel Flextreme is a small family car with a 5-door hatchback body styling with 5 seats.

In January 2008, a rebadged version of the concept was introduced at the North American International Auto Show as the Saturn Flextreme.^[3] The Opel Flextreme is expected to emit 40 grams of CO₂ per km or less (according to European test procedure ECE R101 for range extender vehicles).^[4] It is expected to reach approximately 153 mpg_‑US (1.54 L/100 km; 184 mpg_‑imp).^{[citation needed]}