This is $5k for 2 kW * 24 hours. So 3 of these at $15k total would roughly replace my $700 generator + $10 worth of gasoline for emergency situations.

To truly run my house where it would be adequate at 20 kW or 24 hours or so, I'd need 10 of these at $50k. To run my house of for a week (where I live, the last major power outage lasted three weeks), I'd need $350k. For that amount of money, I can just buy a very nice house in Florida and go down there when the power goes out.

Now, if I go top of the line, I can get a 22kW generator (http://www.homedepot.com/p/Generac-22-000-Watt-Air-Cooled-Au...) for $4,700 + gasoline at $2.30/gallon where I live. This will not even require me to go out and start the thing as it kicks on automatically, much like a battery backup does.

Battery powered houses just don't make sense cost-wise, and at this price disparity it's not a question of spending a little more: $350,000 vs $4,700. That's two orders of magnitude. It's not the clean option, but given that it's standby power, I'd rather see us invest in more efficient power plants (nuclear and wind) than home batteries.