I don't think it actually produces 1.5V per cell, like the first page shows. I can't remember, but I think it's less than that.
LoL, but I find it really funny to see in the following pages they are suggesting 8 feet deep, and the deeper you go, the more amperage. Or combine in parallel as well.
You could spend thousands on the materials for a few batteries
On the other hand, if you got a bunch of scrap laying around, hey...why not. It may make a good battery trickle charger