Graph of the Day: German Solar Energy Exports
- Jul 16, 2013 9:00 pm GMT
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Here is a rather obvious cycle. Solar power output goes up during the day, and down to zero at night. Remarkably, Germany’s electricity imports and exports now follow an identical cycle. Electricity is exported when the sun comes out and is imported when it goes down. At least during summer. Here is what happened in June this year:
The peak in exports and the peak in solar power is more or less identical. So, when the sun comes up German power prices go down (relative to its neighbours) and it starts exporting power. When it goes down German power prices go up (relatively speaking) and Germany starts importing power again.
You can also see that exports increase significantly when it is very windy on the 2nd June.
This shows just how difficult it is to work with high accuracy how much renewables, or nuclear, reduce emissions. Not only do you need to consider what renewables are displacing within a country, but also what is displaced via exports. And if you want a real mental challenge try estimating how much Danish wind farms reduce emissions. Denmark more or less has two electricity grids, and often imports and exports from and to Sweden and Germany at the same time. And does a MWh from a Danish wind farm that displaces a MWh of Norwegian hydro reduce emissions at all?