That was a question by John D. Morgan directed at me with this tweet. This is an interesting question. I don’t know the answer, and I think no one can know the exact answer, since it depends on future developments. It also depends on what phase out one is talking about. I will assume that it is the decision in 2011 and therefore contemplate as alternative what would have happened under the earlier 2000 phase out decision without the 2011 one.
The simple answer would of course be “zero”. Some people point to the fact that Germany, as a member of the European Union, is part of the Emission Trading System, which puts a hard limit on all emissions from large installations (power plants are included) in Europe.
That of course means that whatever additional CO2 gets emitted in Germany will be canceled out by less emissions somewhere else.
But I think that is too simple an answer.
That’s because the absolute cap could be reduced faster if CO2 goes down faster than the 1.74% per year required by Article 9 of Directive 2003/87, as amended by Directive 2009/29. People could say “wow, we have all this low carbon electricity from German nuclear power plants, let’s get that up to 1.89%” or some other value.
That’s the part where any answer to the question necessarily involves prediction of future policy decisions. If one assumes no change to the 1.74%, well, the answer to the question permanently remains zero.
So then, how much low carbon electricity is gone because of the 2011 phase out decision?
For discussing that, one needs to know that the nuclear phase out in Germany already was decided in 2000 by an agreement between industry and the government, which was later (in 2002) incorporated into law. From 2000 on, nuclear power plants were allowed only a limited number of electricity production, which was set at 2482,18 TWh. See this source from the German government (in English).
Of that number, 980.7 TWh was left as of December 31, 2010. From that one needs to subtract production of 2011 (108.0) and 2012 (99.0) (Arbeitsgemeinschaft Energiebilanzen), which leaves us with 773.7 at the end of 2012.
With the remaining operation periods under the 2011 decision maybe some of that low carbon energy won’t be able to be generated. Maybe they all need to shut down before generating their remaining energy.
But if you look at the German Wikipedia article on nuclear power stations in Germany, there is a nice table on when which power station will be phased out under the 2011 decision, and when that power station will shut down because it has no allotment left.
For all of the remaining 9 plants, the shutoff date under the 2011 decision is actually later than that when remaining generation allotments run out.
So that would be, again, zero TWh in low carbon energy lost to the 2011 phase out. Disclaimer: I have not checked the calculations at Wikipedia. But they do seem to make sense at first glance. The 773.7 TWh remaining at the end of 2012 are only about 77 TWh per year until the final shutdown of the last three power plants on December 31, 2012.
So, to sum it all up: The answer to the question is “zero” if one does not assume that a large lost number of low carbon energy would have brought faster reductions than the 1.74% per year. But the “large lost number” seems to be zero as well, since there was already a cap on nuclear in place since 2000, and the 2011 phase out doesn’t do much to accelerate what would have happened anyway.
This result is slightly surprising to me, I would not have expected it before writing this post. So thanks again to John D. Morgan for asking this interesting question.