Actually though, I do agree with that bit: you really can't do much better than solar and wind for simplicity. And I believe since this article was written, it has only gotten better.
But, battery technology has been at a standstill for a while. New battery technology seems as far away as cold fusion some days. And without battery storage, I don't think you could really serve the world's power needs with just wind and solar. (But I'm also 100% a layperson, so hell if I know.)
Battery technology has been as far from a standstill as it would be possible to be. New chemistries, new electrolytes, new anodes and cathodes. Batteries are improving faster than almost anything else.
But most of the world's energy storage is not and will not be chemical batteries.
people forget hydro - the most sustainable and cheap energy source.
you can use hydro power as energy storage as well, just pump some water back uphill into water reservoir and use it later to generate electricity when you need it.
that way you can store energy in form of potential energy of water
But, battery technology has been at a standstill for a while. New battery technology seems as far away as cold fusion some days. And without battery storage, I don't think you could really serve the world's power needs with just wind and solar. (But I'm also 100% a layperson, so hell if I know.)