UN sees $15 trillion global renewables investment to keep emissions in check - POWER-GEN WorldWide

You don’t need much of a share of this to be implemented to see the upside in solar over the next 20 years.

http://www.powergenworldwide.com/index/display/articledisplay/7267753456/articles/powergenworldwide/renewables/wind/2011/05/un-sees__15_trillion.html