How sustainable is exporting excess power?

This weekend I found the Agorameter. It is a tool that shows German electricity data in real time. Not only production, but also import/export and prices. Initially I just used it to compare with the Belgian situation, but after some playing around, there was something that surprised me. Just look at this screenshot of the import/export of Germany:

I heard many times that Germany exports a lot of its electricity to its neighboring countries in the context of the energiewende, but I certainly didn’t expect it to be that much. It is clear that Germany exported much more than it imported last week. This is mostly being reported as a positive thing: much more electricity is produced than what they can use, so they can export their excess. But there is much more to it than just that and not all of it is as positive.

Let’s start with the most obvious. Wind and solar energy are intermittent energy sources. They produce energy when wind is blowing and the sun is shining. With little wind and sun → not much production. With much wind and solar → huge production. When increasing the capacity of those intermittent sources, the valleys will not be that deep, which is good, but the peaks will be growing too. Doubling a small number will not make much of a difference, but doubling a large number might be. Just look at the solar/wind production during last week:

We clearly see that there was not that much production of wind and solar in the beginning of the week. There was a lot of production of wind and solar in the weekend (when energy consumption is lower in the first place). We see a range of production of wind/solar going from 2% of consumption (Friday, February 19 at 06:00 when advancing to the morning peak when more energy is needed) to 58% (Sunday, February 21 at 21:00 when the evening peak is already over and less energy is needed). Luckily that weekend production peak was in the evening hours and not during a sunny day, this would have even add to the production.

Just imagine what would happen in such a situation when Germany would manage to double its wind and solar installations… At its lowest there still will not be much production. But at its peak, production will go completely through the roof.

Germany, being hailed as an example how to do the transition, it was a surprise to me to see how little balancing was done. This balancing was done in the first place by coal and also somewhat by natural gas and lignite. Pumped storage capacity is ridiculously low and was even used at peak production by wind. So what they seem to do is using the international grid as some kind of a battery. I can understand why. It takes away the need to make (huge) additional costs of storing that excess energy at peaks in order to put it to use when production is low. I am not really sure if that is sustainable.

Just imagine what would happen if all countries in their neighborhood would do the same. Belgium is following Germany’s example and is building more wind turbines without any measures to shave of the peaks. Also the Netherlands and United Kingdom are betting on wind energy. Even France seems to start taking steps in that direction. Suppose we all become dependent on a considerable share of solar and wind energy for our electricity needs and there is a huge production by wind and solar. Then we all would have the same problem at the same time. We all would want to export that excess. But then who will be there to absorb it?


1 thought on “How sustainable is exporting excess power?

  1. TinyCO2

    Unlike solar that is largely uncontrollable, wind power can be turned off if there’s too much production.

    However, Germany sometimes has to pay other countries to take the electricty, and it’s making even Switzerland’s hydro uncompetative. Those who dream of 100 renewable power, consider pushing electricity ebb and flow over more and more countries in the hope that the irregular waveforms can be ironed out. Weirdly it usually ends up with a vision of massed ranks of solar in northern Africa. I’m guessing that World Peace is on their to do list.

    The next problem on the agenda is aging. Windmills don’t last as long as conventional power and the more usefuls ones at sea are aging even faster. Maintenance is turning out to be as expensive as putting up new ones. The carbon fibre blades can’t be recycled. Last I heard, Denmark was dumping theirs at sea. It’s all a massive white elephant.



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