[TrainedMonkey]

The missing link is to build up solar capacity to refill your battery.

To refill the battery you need to generate 57600MWh each day. Assuming that we get 12 hours of sunlight per day at 50% efficiency, you that comes down to 2 (efficiency factor) * 57600MWh / (12 hours / day) = 9600 MWh solar installation.

At $1 / Watt, 9600 MWh solar installation comes down to $9.6 billion.

Assuming my math is correct, this seems pretty competitive. In particular, I am assuming that $1 / Watt means $1 per Watt of electricity at max luminosity. If $1 / Watt means $1 per 1 Watt of absorbed solar energy, the efficiency should be 10% - 15%.

Large scale installation cost per watt: https://www.greentechmedia.com/articles/read/doe-officially-...

[wbl]

The winter vs. summer amount can be far more, and then you have heating costs to provide power for.

[sokoloff]

And not infrequent spells of winter weather that are a week or more long without ever seeing the sun.