Len;
Did I mention the Rods are consumed and that it likely requires more to create those than it will ever extract by galvanic corrosion. What happens when the ph of the soil gets altered significantly enough that the process stops?
Hardly "renewable" energy. It does come up occasionally but I don't believe we have seen anyone actually using one for any useful purpose. Just another toy and science trick but certainly not a true storage device more of a one time source and not quite renewable.
Just the view from here.
A google search yielded a lot of info including my statements earlier in this comment and, no, I did not even look at wikipedia.
Anyway, good luck and please report back any outcomes of attempting this. Always good to have some Macguyver tricks up your sleeve if you get shipwrecked on a deserted island with a container of copper and zinc plated wire, a flat battery and a shortwave radio.
T