The whole story is from AutoBlogGreen but the short version is that this car runs on electricity for 40 miles and you plug it in at night. But, it also has on board a little 1L internal combustion engine that does not produce torque but rather electricity. This keeps the batteries charge level stable and can fully re-charge them in 30 min. It only runs at a single PRM point so it doesn't waste any energy switching gears like normal cars. It can run on normal petrol, E-85, or put in a little diesel engine, or hydrogen, or natural gas .. anything!
General Motors doesn't believe that there will be any one silver bullet to the energy problem. Instead, the future energy supply will be more regionally diversified and decentralized. Energy sources will be based on what is available locally, such as solar, wind, biomass, geothermal etc. Some future vehicles will be driven by hydrogen, some by batteries, and still others for the foreseeable future will be internal combustion. E-Flex allows GM to tailor vehicles to the energy infrastructure vehicles of a given market, such as biodiesel made from wood chips in Sweden or sugar-cane ethanol in Brazil.(link)
I think that makes perfect sense, and from GM from all places. As for the design of their concept I think it is bad ass but I am sure others will hate it. It looks very American in a good way, but its only as long as a Toyota prius.