I've searched for this but if I missed it and it’s already out there sorry. I was wondering if anyone had considered using compressed air as a way to store energy. My father had cabinets built by an Amish cabinet shop, when we were in their shop I noticed a lot of their equipment was run by compressors, if solar panels were used to power an air compressor to fill a large tank/tanks then the air could run machines at night instead of using batteries. I also thought that it could be used to generate electricity. Batteries eventually die, how long do you think it would stay pressurized before it went bad? Do you think a large tank would be more expensive than a bank of batteries? Any thoughts or additions?