Why not go propane for the back up, that way you're not paying a ******* gas company a standing charge.
Actually it's not as brilliant as it sounds. If you work it out (which, sadly, I did once, with the help of a student friend with a pet hamster) the cost of the hamster food is greater than the cost of mains electricity for charging your phone. Not only that, the hamsters have to be replaced every 2 years or so, so there's the capital cost to consider. I suppose you could grow your own hamster food in the garden, but then there'd be the cost of fertilizer etc and (in my case) a gardener to do all the work. There is one massive advantage. Hamsters are nocturnal, so they produce electricity when the sun has gone down.
I wondered about that, but we've got a propane gas tank at our cricket club and they charge us monthly for it. Early days yet and we'll look into all this when the time comes. Interesting stuff though.
Hang about for a few months. There's loads of developments going on in the solar cell field and there's some major breakthroughs expected. These are mainly in the area of efficiency, which means that you will be able to get more power from the same area of roof.
you used to be able to get a nice bit of kit from the pit electricians that had exactly the same effect on a electricity meter,not saying I ever had one like