[trenchgun]

> I imagine that it is cheaper for you to provide energy to the grid (once the grid is already established) than for the power companies to provide energy to the grid.

This is a bit inaccurate. Utility scale solar is cheaper to produce than rooftop solar generally.

But there are a lot of other things in play too, such as markets, subsidies etc.

Also: power companies don't just provide the electricity to the grid, they keep the grid running and in balance. If the consumption does not equal the production at all times you are going to get blackouts.