One process of creating HHO is by arcing two carbon electrodes under water. The carbon molecule attached to the HHO to make a stablized fuel. In otherwards you could generate and store you water gas.

Carbon is a natural conductor and I don't see why it cannot be put into the water in the same way pure silver is used to make colodial silver water. Anyone have any comments on this?

Maybe crushing and making coal into a powder and adding this to the water may make the water conductive enough to generate a high production of HHO. I've heard that coal submerged in water creates a kind of coal gas or hydride. I stand to be corrected.