Siemens just unveiled the world's first hybrid-electric aircraft, the DA36 E-Star. It uses an unique power train to do the seemingly impossible: take off and land on nothing but batteries.

It's received wisdom among pointy-headed energy thinkers that the one thing batteries can never, ever power are airplanes. Pound for pound, even the best batteries store only a tenth of the energy of gasoline, not to mention jet fuel, which is even more potent stuff.

But electric engines are smaller and lighter than their gasoline counterparts, which helps make up for the extra weight of the batteries the plane must carry. The DA36 E-Star's 70 kilowatt Siemens engine powers its propeller, and can draw electricity from a small Wankel combustion engine or from batteries.

It might seem like a toy, but Siemens claims that this system could be "scaled up for use on a large passenger plane," reports CNET. Ultimately, this drive train could save up to 25 percent in fuel consumption.

A battery powered jet engine (or a plane that runs solely on solar power) it's not, but Siemens' solution could represent a reasonable compromise in a world in which liquid fuels are only going to become more expensive.