According to a 2010 report, cost-minimized combinations of wind power, solar power and electrochemical storage could power the full electric grid up to 99.9% of the time by the year 2030 creating the potential for them to become major sources of power for the nation.

via The Energy Collective – The world’s best thinkers on energy & climate http://theenergycollective.com/miashaw/269021/studies-suggest-combining-renewables-can-fully-cover-energy-needs-2030