[JamesP81]

There will be some additional costs for energy storage so you can turn on a light bulb at night and use power at a higher surge rate than the sun is providing.

I'd imagine that you'd probably remain hooked up to the main grid in order to make up any shortfall. It would likely be cheaper than banks of storage batteries, at least.

[P8riot]

Many utility companies will credit you (or even pay you) for power you return to the grid. The night time usage costs, provided they are not excessive (gaudy Christmas lights etc...) could be dramatically offset by such an arrangement.