So far organs have proven to be too complicated to be easily printed let alone made artificially entirely. The only internal organ we even stand a chance at right now is the heart. The heart is surprisingly easy as it's just a sack of muscles, with blood vessels running around it. All the other organs are far too intricate and finely structured.

Looking into the future I would say, that organs grown from your own DNA in Zero G in orbit would be our best bet. A lot of things have to happen to make this affordable.

The most important part to remember about Hydrogen: It's currently made out of natural gas and not water. The ones pushing for Hydrogen right now are fossil fuel companies, because they are producing it.