The truth about Germany's nuclear phase-out | Duncan Clark | Environment | guardian.co.uk:
If you look just at Germany's emissions and you compare "before the nuclear switch off" with "after the nuclear switch off", then you might conclude that turning off atomic plants cut carbon emissions. But that would be the wrong conclusion. For one thing, the carbon savings in Germany were – as Carrington points out – partly or perhaps entirely the result of a mild winter. The obvious point here is that if you'd had the nuclear plants running and a mild winter, emissions would most likely have been lower still.
More importantly, though, in a continent-wide energy market it doesn't make sense to look only at Germany. You also need to consider the implications of the fact that switching off the nuclear plants led to Germany's exports of electricity falling through the floor – by a massive 63 trillion units, according to Carrington.
Unless you think the countries which would have used that power simply turned the lights off, the unavoidable implication is that somewhere a bunch of fossil fuel plants were ramped up to pick up the slack. And not just any fossil fuel plants, but those with available capacity – which will generally mean dirty old ones because the cheaper and more efficient ones, along with all the renewables and nuclear, will already have been working at full capacity.
The core point is this: until we get a 100% decarbonised grid, the marginal impact of turning off any existing low-carbon electricity source – or indeed adding to demand by switching a light on – is virtually always to add more coal to a power station.
