I think you're looking at this only from an economical point of view and not factoring in environmental concerns. In CA, though solar continues to be installed

I think you're looking at this only from an economical point of view and not factoring in environmental concerns. In CA, though solar continues to be installed, we've reached a point--due to a lack of good/cheap storage ability--that at the end of the day (where Solar has been working fine all day), in order to meat evening demand, the only way to address steep demand is to fire up coal-fired plants. They work, but they're not only expensive, they're dirty.