Yes you will still need some kind of power supply, you can set up a node with a UPS too so that it gives you time to spin up electricity again like a generator and keep your node operational, or have a fall back node in another region of the world that will manage async payments for you so you can just send or receive funds when you get internet access or if you can broadcast a signal to someone who has an internet connection.

I don't think the tech is really geared for that use case yet, but its coming and Africa is a great testing ground for it, if it can survive here, it can survive anywhere lol