Original sentence: "It uses more energy than present in the bond itself" said X.According to X this concept violates the first law of thermodynamics and is met with much skepticism.Car prototypes seemingly powered by a water fuel cells have been assembled.The water fuel cell is a device that breaks water into hydrogen and oxygengases.The water fuel cell was claimed to produce several times more energy than it consumed (for instance, by connecting it to an engine that would burn the hydrogen back into water)
Edited sentence: Since this concept violates the first law of thermodynamics  it was met with much skepticism.The water fuel cell is a device that was supposed to function by breaking water into hydrogen and oxygen gases using less energy than that present in the bond itself.The water fuel cell was claimed to produce several times more energy than it consumed (for instance, by connecting it to an engine that would burn the hydrogen back into water), and a car prototype powered by a water fuel cell was assembled