Well. I mean, if you'd like to know, it's specifically for the practical application of macro-robotics. Not to be confused with the programming definition of macro, but for the powering of large kinetic structures.

See, one of the biggest problems that modern robotics is facing isn't actually how to generate power, but the storage of it. In order to power a structure of sufficient size meaning anything larger than a dog, the size of the battery would have to be huge. Infeasibly so, to the point where the vast majority of the robot's bulk would just be for power storage. A way to subvert this is to make the power source a generator that is constantly renewable.

So you would think! You'd think, why not go with kinetic energy, or solar? Those would still require storage! The structure has to be able to draw upon power before it moves, or if it's in the dark. If you have it drawn directly off its generator however, then you just have to worry about safe harvesting and capacitors and bypass the storage stage altogether!