Interestingly both of the use cases you mentioned are quite amenable to demand response. Big freezers can be set to a few degrees cooler and be switched off dur

Interestingly both of the use cases you mentioned are quite amenable to demand response. Big freezers can be set to a few degrees cooler and be switched off during peak electricity demand. In [1] the researchers even call them "ideal candidates for implementing demand response strategies". For aluminium smelters, you are correct in that they can't be turned off entirely (the cryolite will solidify) but it is often possible to reduce energy demand significantly by stopping the electrolysis reaction but still heating the mixture to keep it molten. Then later, when peak demand has passed you can switch on the electrolysis process again. [1] https://www.osti.gov/servlets/purl/1237687 https://www.osti.gov/servlets/purl/1237687