Both steel and aluminum production depend mostly on the cost of energy, so any improvements that would make aluminum cheaper would also make steel cheaper. Stee

Both steel and aluminum production depend mostly on the cost of energy, so any improvements that would make aluminum cheaper would also make steel cheaper. Steel also has the benefit of being ferromagnetic so it’s a lot cheaper to pull scrap steel out of the garbage stream and recycle it, but that depends on having lots of scrap steel to begin with. There’s really not a lot of room to make aluminum as cheap as steel, as all economies of scale have by now been mostly realized. The cost of energy is so dominant that it makes sense to run smelting plants idle most of the time with the crucible heated constantly just to take advantage of negative power prices (although there are other factors at play like subsidies and national security concerns). Barring some sort of seismic scientific breakthrough in metallurgy, the current ratio of 2-3x the cost of steel is here to stay. There’s maybe a little room if we reach “peak aluminum” as the fraction of recycled scrap approaches 100%, but I don’t think that would make that much of a difference because we’re likely to hit “peak steel” before then (and again, its just easier to recycle from a logistics standpoint).