[tgflynn]

In that case how far are we from being able to supply all US electric needs with solar ?

I think I've heard that with current solar cells you could produce that much power with a 100 mile x 100 mile installation in a sunny location.

If battery storage and power transmission are solved problems, are the obstacles now only economic ?

[Retric]

Wind and Hydro are going to be part of the mix. So, outside of Alaska it’s largely a question of economics at this point. We already have huge investments in Coal and Nuclear which are being phased out of the market. But, cheap natural gas is a very different beast. As long as supply is abundant market forces are going to keep the price low enough to be attractive vs storage.

IMO, we are headed to about 70% renewables in 30 years baring major changes.