Hydrogen Photobioreactors (Hydrogen from Algae)
Currently the only way to get Hydrogen is from Ice. The ice gets melted in the Oxygen Generator and the Oxygen & Hydrogen are reduced down from the resulting water.
Oxygen can also be produced by Oxygen Farms, which are a kind of Photobioreactor... so why not a similar thing for Hydrogen too?
Given certain conditions, some types of algae, when deprived of Sulphur will swap from producing Oxygen to producing Hydrogen.
On Earth this tech is limited by economic factors such as the amount of land required for production to be on a viable scale and the difficulty in maintinaing the correct conditions for Algae to produce Hydrogen... but in space and 60 years from now...
We wouldn't even need a new block (though one might be nice) - presumably the bioreactors we're already using as Oxygen Farms would comprise of algae...
Flip a toggle switch on the control panel and deprive that Algae of Sulphur and voila, it produces Hydrogen instead.
Or the toggle switch could represent swapping the type of Algae in the tank for a strain that's more efficient at producing Hydrogen than Oxygen.
Or sure, we could have a whole new block dedicated to Hydrogen if people want that...
Either way the science is sound and we do need an alternative way of obtaining Hydrogen.
Production would be about the same as an Oxygen Farm, so quite slow unless you build lots.
If anyone's interested, here's how it works...