Last time, I introduced Europe's ambition to produce its electricity 100% from renewable sources. (Their plan is technically possible, although politically infeasible.)
Now a state in the United States claims it can do that kind of things, too.
The author of the paper did a great job. He field-measured availability of wind (3 sites) and solar (3 sites) energy over 123 days (in January, July, October, and April).
1. Complementary sources of renewable electricity
1) Day vs Night
Day: Solar radiation is strong.
Night: Wind blows stronger than it does during daytime.
2) Summer vs Winter
Summer: Solar radiation is stronger than that in winter.
Winter: Wind velocities are higher than those in summer.
12%: biomass cogeneration
100%: renewable electricity
Here, 100% means that renewable power measured in 2009 could sufficiently meet all the average hourly loads of North Carolina recorded in 2006.
3. Means to solve the intermittency of wind and solar energy
2) Pumped Storage
3) Ice Storage
I don't think many people will buy the 'ice storage' idea, while the stable supply of hydroelectricity and the potentials of pumped storage are well-known.
However, the idea of complementary wind and solar is very persuasive.
I hope the administrative authorities in North Carolina could put this grand plan into practice!
Source: Blackburn, J. (2010). Matching Utility Loads with Solar and Wind Power in North Carolina Dealing with Intermittent Electricity Sources. Takoma Park, MD: Institute for Energy and Environmental Research. Retrieved from http://www.ieer.org/reports/NC-Wind-Solar.pdf