Hansen is wrong. I think in general the two part article I linked to rebuts this. Here is the link again.
Jacobson, Mark Z. and Mark A. Delucchi. 2010a. "Providing all global energy with wind, water, and solar power, Part I: Technologies, energy resources, quantities and areas of infrastructure,and materials." Energy Policy. doi:10.1016/j.enpol.2010.11.040. www.stanford.edu/group/efmh/jacobson/Articles/I/JDEnPolicyPt1.pdf
Jacobson, Mark Z. and Mark A. Delucchi. 2010b. "Providing all global energy with wind, water, and solar power, Part II: Reliability, system and transmission costs, and Policies. "Energy Policy. doi:10.1016/j.enpol.2010.11.045. www.stanford.edu/group/efmh/jacobson/Articles/I/DJEnPolicyPt2.pdf
Wind is a variable source, but it blows at different times in different places. So connect widely dispersed wind sites, and it becomes closer to reliable. Solar energy tends to be available in a very different pattern than wind.Now add solar to a grid with a lot of wind, and becomes still closer to reliable. Add some storage and it becomes reliable most of the time. Add some hydroelectricity and geothermal to fill in when wind and sun both die, and it does become reliable. If that does not quite do it, you can provide 2% of your power from natural gas or biogas.
Incidentally nuclear and renewable are not complementary. If you have a lot of renewable energy, then you need shaping energy, on demand energy. Nuclear is baseload. If you use it for shaping you waste most of its capacity and it becomes extremely expensive. If you have a lot of nuclear, using nuclear for base load and maybe for load following, you need peaking power and spinning reserves. Renewables (except hydro and geothermal whose potential are limited) are lousy for that. So if you want to go carbon free you go nuclear or renewable. Splitting this baby just gives you a dead baby.