Add product of green iron

[nworbmot]

I.e. iron ore reduced with hydrogen to HBI.

[DiederikJaspers]

Perfect idea to add HBI/DRI iron!

But this 'vector' for hydrogen can work reversibly quite efficiently by feeding of steam. So iron can act as an energy dense storage medium (IRHYS, https://www.wevolver.com/article/iron-based-hydrogen-storage) for hydrogen, which can be shipped like methanol and ammonia.

Aluminium, having an even higher energy density, would also be a possible candidate to offer a reversible redox reaction, but has a higher complexity due to the presence of a dense oxide skin.