The big unknown to me here is the impact of the interconnects. It's obvious that the intermittency problem gets smaller with better transmission infrastructure.

The big unknown to me here is the impact of the interconnects. It's obvious that the intermittency problem gets smaller with better transmission infrastructure. What I can't recall seeing is actual studies of how much transmission capacity would be needed to average the renewable input over large enough an area so that existing storage solutions are adequate. Also, not all renewables are intermittent. Apart from hydro, geothermal comes to mind. (Although with climate change-induced changes in rainfall it's not clear that hydro will be reliable on the timescales we talk about either....)