Hydrogen is looking more and more dubious as a useful tool for decarbonising. Not withstanding the murky nature of hydrogen's many names, it's just so difficult to transport, and store, and... more.

Now one of the use cases I believed was sensible - hydrogen as a reduction element in steel manufacture - looks as dubious as rainbow hydrogen.

The Economist recently described a cheap and efficient way to upgrade existing Steel Plants to remove the need for coking coal in steel manufacture, and to produce oxygen as a byproduct. And it uses a new spin on the Perovskite family of minerals.

The modification ... cuts coke out of the loop by pumping CO directly into the blast furnace. The clever bit is where this gas comes from. It is made by capturing the CO₂ produced in the furnace and recycling it by splitting it into CO and oxygen. The oxygen thus released can then be used in the second part of the steelmaking process, in which that gas is blown through molten iron in a differently designed furnace, to burn off part of the carbon now dissolved in it and arrive at the optimum ratio of iron to carbon to create the type of steel required.

With a pay back in a few years due to the removal of expensive coking coal from input costs it is likely that this process, or one similar, will be the future of steel manufacture. New hydrogen reducing steel plants would take decades to build out and replace existing plants. Modifying existing ones, with a short pay back is a no brainer.

No more rainbow hydrogen - which is a silly name. Hydrogen is colourless - like its future.