Opel Flextreme

This showcases “E-Flex,” the latest thinking from GM’s European subsidiary on how its gargantuan investment in fuel cells and electric drive might — eventually — lead to real cars for real people. The core principle of “E-Flex” is electric propulsion, with the clever bit being that there are many possible sources for the electricity. In the terrific-looking Flextreme, the source is a small diesel engine linked to a generator (not the wheels). It will supposedly burn just 1.5 liters per 100 km (155 mpg), and emit 40 g/km (or 40 g/.62 mi.) CO2. The Segways in the trunk may be a fantasy but the diesel-electric idea isn’t — it’s been used in diesel-powered trains for decades.