I like to tell my physics students this story. A man made a perpetual motion device, and dared the community to disprove him. After several had tried and failed, a physics professor looked at the layout of the device. In the center was a permanent magnet. He took reading of the magnetic field strength of the magnet, ran the machine for a day, and then measured the field strength a second time. The permanent magnet was being demagnetized by it’s operation. What the man had done was turned the magnet into a limited fuel source.

This was fine and didn’t violate any conservation laws: the energy for the device was originally from the magnetization process that created the magnet. It actually was quite cleaver. One could just chuck a new magnet in every once and a while and the machine would keep running. The fuel source was also quite small. But, all things must be practical and efficient if they are to be industrally implemented. The process of creating permanent magnets is quite wasteful. The amount of gas needed to generate an electromagnet strong enough to create the permanent magnet was actually more than the gas needed to produce the movement from the perpetual motion device.

Though disproven, the professor said that this was on the right track. “Instead of magnetic storage, while not use electric storage devices like super-capacitors? They are much more efficient, both because they have much less loss in creating them, and because the efficiency of electric generators increases with size - and we have a very efficient electric distribution system that connects us to giant generators already installed in every home.” Soon after, electric cars became a thing.