I don't think they mean this as power storage, rather, shifting the location of power usage to the place where power prices could be ridiculously low. Smelting

I don't think they mean this as power storage, rather, shifting the location of power usage to the place where power prices could be ridiculously low. Smelting bauxite is an energy-intensive process. If you do it in China, you need to import the energy to do it. If you instead send bauxite to KSA they could use their cheap energy and send the resulting aluminum to China. It's not storing the energy, it's making energy storage and transport a redundant step.