I think they would need free electrons as the result of a chemical reaction, not just a voltage? For an organism to make use of a high voltage, it would need to physically connect to a lower voltage and allow current to flow, which is not possible for a microorganism that small given that the high voltage lines are isolated by several feet.

Cool concept for a GMO electro-snake though.

Yah, I think they feed off ions, not voltage.

There are similarities, but they are not the same.

Trees evolving the ability to grow taller left large forests of dead lignin (tree trunks) lying around with no natural bacteria to decompose it. It's similar to our modern landfills and plastic patches in the ocean. Eventually life finds a way to use it.

Extremophiles have evolved and live around volcanic vents, so I wouldn't put it past nature.