Comment by jwingy

A significant impediment is handling peak usage power. Maybe solar can provide most of our energy needs, but for those times where peak power is needed, it's probably more sensible to take a more balanced/mixed approach.

*edit looks like the article has a convenient link to another article talking about this exact problem:

http://www.vox.com/2016/2/12/10970858/flattening-duck-curve-...