It's because local photovoltaics can save a lot of infrastructure and can require nearly no labor.
You don't buy cold air piped from across the city, you make it locally. Why?
You don't buy cold air piped from across the city, you make it locally. Why?
In Sweden it is quite common to pipe hot air (and to a lesser extent cold air) across the city rather than each house making it locally. Once of have the basic infrastructure in place it is a lot cheaper and more efficient.
No, they don't. You still need almost the entire national power grid to supply your home with night-time electricity... That infrastructure won't be going anywhere.
An even worse outcome will be every home having local power storage infrastructure. Tens, or hundreds of thousands of dollars for a power wall, or a compressed air storage system is much more expensive then maintaining the grid.
"Just buy a $15,000 PowerWall, which you will need to replace every 10 years" is, compared to grid electricity, incredibly wasteful.
There's a reason why customers and users overwhelmingly prefer centralization, even if its harmful for them in the long-term. It's cheaper, and people would prefer it to be someone elses' problem.
There's also the matter that if, say, 40% of the population disconnects itself from the grid, that doesn't mean that the cost of maintaining that infrastructure will drop by 60%. Someone will have to pay for it.
You are right that it does not yet work out, it's $0.17/kWh for the powerwall (assuming you fully charge/discharge it each night) + cost for panels. Given that grid-disconnected users would want some buffer, an off-grid system probably works out to ~$0.40/kWh all in for battery-stored electricity
You could save a big chunk of this by some habit changes, most of the cost comes from the batteries, so scheduling energy intensive activities to run during the day reduces your cost for them to $0.10/kWh or so.
Honestly I am surprised how close these numbers are. I initially was sure the grid would survive in cities, but now I am not so sure. In 10 years these numbers will likely be half what they are now (batteries in particular will be way cheaper). It might all be enough to kill the grid in many places.
Photovoltaics can¹ change the other side of the equation² so that locally generating it would be better.
1 - But it's not certain by any means. The current biggest obstacle is battery storage and maintenance.
2 - losses and infrastructure costs vs. gains from scale.