A Plane That Runs on Hydrogen

Boeing has successfully tested the world’s first manned, hydrogen-powered plane, the BBC reports, with one executive calling the three flights in Spain “a historical technological success.” The propeller-driven two-seater runs on a hydrogen fuel cell that emits only heat and water. Boeing engineers say they doubt the cells alone could power full-scale passenger planes.

With the airline industry concerned about greenhouse-gas emissions and rising fuel costs, it’s more likely the cells will someday contribute to a hybrid fuel system on big jets—and even that could be decades off, one engineer said. Other hydrogen-powered planes have flown before, but never with a human pilot; other manned prototypes are in the works, including several from NASA. (More clean energy stories.)