From what I have seen of him, Shellenberger is a single issue nuclear advocate. He has an awful lot promoting nuclear, and little else. The few pieces I have read seem very sloppy on fact. I haven't the time to debunk and cite point by point, but to try and give a little food for thought:

+ He mentions storage once, talking of 1931. No mention of interconnects, dismissal of hydro, but no mention of pumped storage or batteries. Nothing about the appropriate selection for the location, just "solar and wind". It's an empty rant, not a credible case or decent article. There are decent criticisms of renewables, but this is not one.

+ No one in their right mind promotes 100% wind and solar only, without storage, interconnect or base to cover intermittency. UK has, interconnects to other countries - to export when there's excess and import when there's deficit, and significant pumped storate, and some nuclear. Only those seeking to disingenuously discredit talk of 100% wind and solar. The right answer is the correct mix of renewables for each country, taking account of latitude, climate and surrounding interconnects, storage possibilities, geothermal potential etc.

So no, I can't name a country with 100% solar and wind, without other sources and storage as it's not a sane, or even proposed solution anywhere. There's only a tiny number of states that hit 100% by renewables of all sources - the world has been avoiding this climate thing for 50 years.

+ Now you look to a smart and flexible grid. To cope with and capitalise on many smaller often intermittent sources. When it's windy in the north, it might be calm in the south. Albania is 100% renewable generation - mainly from hydro. They still have excellent wind potential, and are building wind to Interconnect into the European super-grid[1]. The chances of it being calm in Albania and UK at the same time are vanishingly slim. Those with an agenda for other sources spin use of interconnect as failure. "oh, Denmark had to import", etc. Yet it's one of the design goals. Which is why dozens of new interconnects are proposed around Europe. USA would do similar but with state level interconnects, along with Canada and Mexico.

+ By 2025 UK will have, I think, 40GW of wind for a grid that requires 30-40GW. Intermittency of wind is covered by (at present) biomass, pumped storage, solar, gas, hydro and interconnects. Right now mainly gas, but as said we seem to have peaked and started on the decline. There might be a very unusual day or two where wind is such that 100% of a day's generation is wind, and it will be meaningless but for a silly headline. Mainly it will be a mix of sources, including that pumped storage most days (it pumps at low demand, and fills peaking needs).

+ There's one nuclear plant going ahead in the UK from the six recently proposed, planned and heavily promoted and subsidised by government. Value for money is atrocious. Fifty+ years ago, nuclear was the clear fast route to climate fix. Today, it's fool's gold, purely on cost. Hinkley point C is still being built, has an agreed strike price of £92.50/MWh at 2012 prices, locked in for 35 years, compared to offshore wind that's just gone through the latest auction with a strike price of £40/MWh. That's an insane premium for nuclear baseload. They weren't supposed to hit parity until mid 2020s or 2030! Solar and wind are still plummeting, where will the disparity be in 2050? Build £22bn of pumped storage or add building insulation and other demand reduction nationally, solar, LiIon battery or combined waste heat and power. You could build a hundred GW or more of extra offshore wind for that...

That should be more than enough. :)

[1] https://en.wikipedia.org/wiki/European_super_grid