According to scientists, if an object approaches the speed of light, a stage is reached where the object's speed is responsible for the increase in mass of the object. Beyond that stage, all the acceleration will increase the mass of the object. So where does this mass come from and how this mass created?
Uranium is dug up from the ground, some of its mass is converted to energy in a powerplant, then the energy is transferred all around along powerlines.
It happens to be so that heating an object increases its mass. So when mass of frying pans and boilers and other thing increases, mass of some radioactive matter decreases. Also the mass of a battery increases when it's charged.
Now is it correct to say that the extra mass that appears in a battery that is being charged comes from the fuel in a powerplat? Well I don't see anything wrong in that.
Finally to get to the subject of acceleration, I note that heating an object is about the same as increasing the speed of the object's molecules.