Iron is here used as an energy storage system. That is the whole point. You store excess energy from wind and solar power e.g. in iron to use later. Yes for sh

Iron is here used as an energy storage system. That is the whole point. You store excess energy from wind and solar power e.g. in iron to use later. Yes for short term batteries are better but for say seasonal storage or when power is generated far away from where it is used then metal is better.