One day I have opened some major parts of the map, and watched picture of dozens unused geysers, so there must be a solution how do deal with it, and here I'm proposing you one of them, nothing special with simple mechanics, but must works well. So, system is build near geyser and using it as water source, then via electrolytes it turn H20 into hydrogen and oxygen which are separated. Hydrogen can be used for purposes of power/cooling, and oxygen can be used by dupes. Power grid: