Solar panel -> 12v Battery -> 12v bus
Works fine for caravans and boats. Only need a backup charger in case of emergencies like 6 weeks of rain. Or an English summer.
Next time I wire our house there will be some kind of 12v and balanced serial bus cabling installed so lighting, sensors and switching need no batteries or wireless between themselves, and the MCP can live on a computer in the house with no access to the internet.
Could even have a 12v fridge freezer so the smart meter brigade can't turn it off :)