It's already doubled Duncan, always has been, we pay more than double per KWhr for utilities energy than the US does. Why does only a measure of energy independence appeal to you, why not all, if you have the choice? Even better why not use hydrogen as the backup, its more expensive for now than batteries, but if you were independent of grid, intentionally generating more hydrogen then you need for your own use from solar, you could go into business as a small hydrogen supplier

The revenue from that would make your future installation maintenance and scaling costs zero, as well as making you wealthy :)