You need carbon to reduce the iron ore to iron. Coal to heat and melt the iron. And carbon to harden the iron to steel. If I understand it correctly the innovat

You need carbon to reduce the iron ore to iron. Coal to heat and melt the iron. And carbon to harden the iron to steel. If I understand it correctly the innovation here is that step 1 is done using hydrogen, presumably the heating is done with (green) electricity, and the last step does not bind the carbon to oxygen, so they are carbon emissions free, not carbon free.