Using their data for the UK (2011 weather) and the 2020 technology scenario (rather than the projections which conveniently make renewables and storage significantly cheaper and Nuclear costs constant) and requiring that the system be carbon neutral it only takes very small tweaks to their assumptions to make Nuclear a clear winner. They are assuming by default that countries will be able to use salt caverns for hydrogen storage, which seems unrealistic given the amount of it their scenarios require. Using the numbers they give for steel tank storage instead, it only takes a 5% cost reduction for nuclear (which seems self-evidently possible with economies of scale) to make the optimal solution a 100% nuclear grid.

Right now I don't think people are pragmatic enough for that to be politically viable in most western countries, but that may shift as the adverse effects of AGW start to be more acutely felt (and, hopefully, as more and stricter carbon taxes are implemented across the world).