No it will not not 'pay dividends' in the long run because the coal they are burning now instead of perfectly fine nuclear plants will already be in the air.
No amount of future renewable energy justify this policy move.
But I think they know that, yet have chosen a path that is feasible both socially and economically. The end goal hasn't changed, I still think they're in the process of making a transition that (hopefully) will serve as a template for the rest of us Europeans on the long run. The approach is radically cynical and pragmatic, but I think the future will go to prove that it was the best way forward.
I'm saying that as a citizen of a country that has deep involvement and investment in those "perfectly fine nuclear plants". I can tell you that the dramatic aging of some of the most ancient nuclear facilities in the country is worrying (to say the least) and the shady business we have to get into to get (and dispose of) the needed fissile material is a terrible burden on our ability to be a voice for good on the world scene.
Is burning coal the perfect solution? Surely not. Yet, our neighbors beyond the Rhine are already world-class producers of solar panel, they've steered away from nuclear energy and their ability and willingness to explore energetic alternatives is an encouraging sign for our collective future.
Coal power is about economics, not energy. Germany could easily cover its energy demands. In a wurst case scenario (german pun intended), France and Hungary are able and willing to sell nuclear power.
I think a big thing is the demand of having 100% uptime of the grid for everyone.
If there was a list where you could sign up and get paid for having something like an hour of notice until a power cut of one or two hours I think it would be doable to be less perfectionist about this requirement and actually save a lot of peak demand resources and dirty back-up plants.
That would be impossible to get through. Currently we’re trying to get downtime to below 5 minutes per year for the average German (it’s at 17 minutes per year currently). That’s 4 nines of reliability, with a move to 5 nines. For every citizen. Many people will not even see any interruption for many years.
This means that Google will be more often down for you than your power.
Going from that standard to the constant failures you suggest would be impossible.
No amount of future renewable energy justify this policy move.