You would be MUCH better off looking for hand crank or treadle machines. I've never heard of or seen any kind of solar-powered setup, other than people who have solar systems built into their house and use regular sewing machines plugged into the wall.
Hand crank and treadle machines are still out there. You just have to look for them. I have a friend whose mother passed, he was going to junk her hand-crank Singer because he thought it was worthless but I knew better, sold it on FB marketplace for him. Lots of people like them for remote summer cabins, traveling RVs, etc.