Been thinking (daydreaming) a lot about a fully off-grid house and how in the summer, you get more solar than you need and in the winter you use much more electricity than you produce. What I'd love to see is some sort of system that used batteries for short term storage, and then during the summer, would convert excess energy to a long-term storage format like methane or LNG.

I have not run any numbers on this, but the idea behind it is to stockpile your energy in the summer to be able to make it through the winter without having to resort to some outside source of energy like wood or gas delivery.

I initially thought about hydrogen, but given it's storage density, and the problems that SLS has had with leaks, taking the additional step to convert into methane would greatly simplify storage and use, and likely improve reliability since you'd be able to use COTS products for natural gas instead of custom hydrogen storage