Does that mean all smelters have to use hydrocarbons, if a means can be created to not use them at a cost efficiency that meets the price of hydrocarbons or beats it?
Some here are sounding like a native who complains about oil being used to create heat when he needs to patch his canoe.
That's a pretty darn big "if". Maybe you can do it in a laboratory, but on an industrial scale? We shall see.
“Does that mean all smelters have to use hydrocarbons”
The process of converting pig iron to steel consists of removing some of the carbon from the pig iron. The removal of the pig iron is done by a process using pure oxygen resulting in the carbon being converted to carbon dioxide.
Thus, the steelmaking process doesn’t use hydrocarbons.
Pure heat, whether from the sun or an electric arc, doesn’t do the conversion of pig iron to steel which is what a smelter does.