The problem with a "cost" analysis is that you're comparing apples and oranges. If it was only a matter of cost/kWh then solar and wind would be fine and dandy. There'd be no question that that would be the way to go.
Unfortunately running on unreliable sources like solar and wind doesn't work as our use of the grid presumes stability of delivery and being able to follow load. We're already having problems in Europe due to wind having to be dumped at negative cost on the market (i.e. they produce more wind than we can use); wind being especially problematic in that the power delivered varies as the cube of wind speed. You only get nominal power in a very narrow range of wind speeds.
Now, of course, these aren't problems that are insurmountable, but it would take a substantial change of the grid with large scale long range interconnects (to even out differences in wind/sun) and storage (to further even out e.g. day/night). These costs are substantial, and must be factored in when talking wind/solar.
As it stands now we have the figures already. Sweden with a hydro+nuclar mix where we've switched as much to electricity as possible we emit roughly half as much CO2 per capital as the "forerunner" Germany. If we factor in industry production we're even better of. Germany's getting rid of nuclear means in actual fact that they have tied themselves to lignite coal (the largest source of particulate pollution in Sweden is actually coal power refuse blowing here from Germany and Poland). They pay about three times as much for electricity as we do, and hence do not use it if it can be avoided. They use fossil fuel for as much as is practical. (I.e. heating their houses etc.) Same is true of the Denmark to a large extent.
But with the current government here, they'll finish off our nuclear in short order, and we'll be changing our energy mix to the same dirty mix as Germany in short order. Don't you worry... All in the name of becoming "green". It's enough to make you bloody weep.