Ultimately, projections about demand for aluminum and steel fall into a category of observations with broad significance to the energy transition: 29 that cheap energy drives production of energy-intensive goods. Energy expenditures have been relatively consistent as a share of economic output for centuries. As energy has gotten cheaper, though, we've used more and more of it to produce increasingly functional, energy-dense materials, from plastics to silicon to carbon fiber. This trend will likely hold through a period of decarbonization. Arguments about cheap electricity that fail to acknowledge our appetite for energy-intensive materials and goods -in this case, aluminum and other light metals over iron and steel -risk underestimating the cost and importance of certain pathways toward industrial decarbonization, and overestimating others.