There has never been a denial that shutting down nuclear power plants will result in some level of increase in carbon emissions.
Discussion related to that fact centers in two areas, neither of which is favorable for nuclear when properly analyzed.
First is the claim by the nuclear industry that nuclear has an advantage over renewable because renewable supposedly requires more fossil fuel back up power than nuclear. This is part of a larger argument by the nuclear industry that seeks to exaggerates the significance of the variable nature of wind power.
In fact, as we see with the OP, nuclear power is also intermittent, and the consequences of its intermittency are significant, both in the area of carbon emissions but also in costs for replacement power (being out of service for months and years at a time is not uncommon) and in terms of grid reliability since the unexpected loss of power from a nuclear plant is a far more significant event to the grid than foreseeable variations associated with wind and solar.
The second area of discussion is that renewable energy sources, when properly assembled work in much the same way as the present grid, but the emphasis on energy efficiency and distributed generation, combined with the fact that all of the alternative generation in the system is also renewable, means the problems that go with centralized nuclear are not present with distributed renewables.
Nuclear simply perpetuates the present system oriented around fossil fuels. This means that instances like Germany and Japan are cases where short term increases in carbon emissions are the price of removing the obstacle nuclear presents to moving forward with distributed generation.
See also:
http://www.democraticunderground.com/112715525
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