There are thousands of retro-fit-kits. They are just in pieces, not kits.
It is just solar or wind power. You work out how much energy you use, and then figure out how much solar panels and wind turbines you need to buy to fill that.

Like the Tesla Powerwall. You can buy more for less, it just doesn't come with a spiffy looking cover.

The one thing that is very different when you are living off of battery power is that you can't just plug things in. Like, your TV, it is always on and draining your batteries even when not in use. Off-grid people put a switch going to the outlet to turn it ALL off. Or similar with a power strip.

There are thousands of articles on solar living. To me it is all very simple. But, I guess it needs to be made even simpler for this current generation that never had a shop class.