[bluquark]

The last ten years' experience with renewables has shown that local-scale generation is underwhelming and large-scale deployments are the way to go.

With the exponential recent declines in production cost, most of the cost of solar is now in deployment, not manufacturing the cells. This has made huge desert installations much cheaper per watt than rooftop -- as a result, large-scale installations is where almost all the growth is coming from.

As for wind power, efficiency increases superlinearly with blade length. As a result of this, and improving material science and production/deployment tech, turbines have been getting enormous (Eiffel-tower-sized or more) and no longer fit outside of dedicated wind farms.

As for nation-wide grids, they're are a central part of the solution to solar/wind intermittency (because weather patterns average out over long distances).