I think that the author’s point was the nuclear power isn’t going to be the panacea that McCain or anyone else(including me) thought it was going to be. Seriously, I thought outside of the need for potable fuels, nuclear power could solve all our problems if it wasn’t for those lefty “I watched China Syndrom” idiots who dismiss the benefits of nuclear power out of hand. This article puts forth the idea that nuclear power can be only part of the mix(and to a much lesser degree than I had previously thought).
There is another part of the night time analysis that also bears consideration. Supposing one goes to a transportation system based on battery storage of electricity or synthetic fuels. Then the night-time capacity drop is irrelevant because it can be used to charge cars (at cheaper rates) or provide the heat or electricity for electrolysis of hydrogen for synthetic fuels.
One can also imagine electric powered rail for freight transportation which can, again use electricity at favorable times of the day.
The idiot's thinking is all in the box - replace coal central power by nuclear central power and change nothing else about our energy economy or our behavior. With expensive, and climbing oil, we will have plenty of incentives to adjust our behavior.