For a few hours in May this year Germany got over half of its electricity from solar power. A much hyped event that Bill McKibben claimed demonstrates we already have the technology to solve climate change. However, there is a great danger that selectively reporting peak production of different renewable energy sources will lead to public misunderstanding of the relative merits of different renewable energy sources.
Let’s consider Germany. Yes, it got just over 50% of its power from solar on a Saturday afternoon in May. However, for the entire month it only got 10%. May is also a lot sunnier than the rest of the year, and as you can see below was the best Month this year for German solar.
In contrast, solar PV has supplied about 5% of Germany’s electricity this year. A much lower figure than the hype would suggest. The 50% figure however appears to have become a zombie stat, with a recent New York Times piece claiming that Germany has enough solar to get 50% of its electric from solar (though eventually corrected to say it was only 5%).
I don’t think it would be particularly unfair of me to suggest this is intentionally misleading.
[UPDATE: This post actually got me labelled anti-renewables by Craig Morris, one of the authors of the Energy Transition website. I'll leave it to the reader to decide if this is a fair characterisation.
— Craig Morris (@PPchef) December 21, 2012
Why is selective reporting of “record highs” potentially damaging? Let’s consider a simple system with 30 GW solar PV and 30 GW onshore wind. In more or less every country in the world onshore wind will generate significantly more power than solar, at least double in most cases. On the other hand the “record high” recorded for each will be about the same. In simple terms reporting record highs makes solar PV look far better than wind than it really is. This is a problem because in countries such as Germany it is wind power that has the real potential to power countries, and not solar. You can see this by looking at the monthly variation in solar and wind power this year, keeping in mind Germany’s electricity use peaks in Winter, not Summer.
Wind has the potential to supply over 50% of Germany’s power. Solar on the other hand cannot, or at least it will require huge energy storage options. The lack of sunlight in winter is a problem that no technological breakthrough can fix.
A final point. Germany getting 50% of its electricity from solar one afternoon may turn out to be less a sign of just how much electricity it can get from solar, but perhaps how little it will get. In May Germany had a total installed solar capacity of 26 GW. Doubling this capacity will clearly lead to it regularly producing more electricity from solar in Summer than it really needs. By coincidence, or not, Germany has recently decided to completely end its feed in tariff for solar panels when installed capacity reaches 52 GW. At this stage it will be producing about 10% of its electricity from solar.
Unless Germany can put large scale energy storage in place, then this appears to be a likely place to end new solar in Germany. The alternative is a flood of useless electricity in Summer, and even more increases to consumer electricity bills. Another alternative is that solar reaches grid parity, and householders continue to buy solar panels in the belief that they this will mean they have to pay less for electricity, all the while pushing up the costs of the electricity they are trying to avoid paying for. An absurd possibility, but maybe not that impossible.