This idea is not the same as something like a capacitor or battery. This perhaps store each individual electron inside of a container not attached to an atom. I guess an electron not attached to something like an atom are as a free electron. Compared to something like a capacitor or battery have a solid perhaps conductive material which store each electron inside of.

Also like regarding with each electron is perhaps since an electron does not stop moving maybe like as zero point energy then perhaps can be used to generate energy. Also listed other possible ways could generate energy in this post.