A couple days ago, I came across this curious message from a wind energy news site from the Netherlands (translated from Dutch):
German economy runs on green energy
Germany can generate sufficient electricity from solar cells and wind turbines to run the entire German economy. Last Sunday, 45.5 gigawatts was delivered (according to Agora Energiewende). There was even a surplus during 15 minutes. Despite that, our Eastern neighbors are expanding clean energy
A quarter of an hour the price dropped under €50 per megawatt-hour because of the oversupply. The Danes delivered 140% of the demand for cleaner energy last year with their windmills and solar parks. Already now they are looking for good storage in order to store surplus production of green energy.
That didn’t make much sense to me. If it is really true that wind and solar were sufficient to run the entire German economy, then how is it possible that there was only 15 minutes of oversupply? Wind and solar are intermittent, it would be one in a gazillion chance that the output of wind and solar coincides exactly with only 15 minutes of overproduction…
It was also rather sloppy reporting. The last sentence of the first paragraph was for example cut off and, although the article was about Germany, in the second paragraph Denmark was mentioned out of the blue. Was this the intention or did they wrote “Denmark” in stead of “Germany”? Or was the connection explained in the cut off sentence in the first paragraph? My guess was that this was a badly executed copy/paste from an article somewhere else.
My guess seemed to be correct. The original article was published in a Dutch news paper. There was the same cheering, but at least it had somewhat more information about what was going on.
The information was still confusing though. The story seemed to be that on Sunday May 15, wind and solar produced “45.5 GW” while the demand was “45.8 GW”. I read the same figures in other cheering media reports and that didn’t make any sense. 45.5 GW is a capacity, not a production and 45.5 is lower than 45.8 anyway. So how could they claim that production was sufficient to match consumption with even a small surplus? Time to go to their source to look what really happened that day.
This is the energy generated by wind and solar compared to the consumption of that day according to the Agorameter:
Firstly, the production from wind and solar was well below the consumption during the entire day. Wind and solar reached their peak production at 13:00: solar had a production of 16.227 GWh and wind of 22.246 GWh. Together that is 38.473, while the consumption at that moment was 58.199 GWh. That is 19.726 GWh short of being sufficient, even on the maximum production.
Secondly, production was at that moment more than 12 GWh higher than the published value of 45.8. Even when we take biomass and hydro into account, we don’t even get production at the same level of the consumption. Not even close:
Production stayed well be production even if we include biomass and hydro. So what about this claim? Maybe the production matching consumption was on a very brief moment in which solar peaked and consumption temporary dropped? Or maybe those who were looking at the Agorameter graph on Sunday saw incomplete data? It is explained below the graph that there is a delay in the gathering of some data and if they didn’t look at this, they maybe could get the impression that the power supply in Germany was covered completely by renewable sources?
But even if we assume that renewable production matched consumption, then I can’t really understand what the cheering is all about. This is probably only during a really small time frame and for the rest of the time wind and solar were NOT matching the German consumption.
More, May 15 was a Sunday and on Sunday most economic activity is very low anyway. So claiming that renewables were running the entire economy on that day is a bit stretching the truth. Even more, it was an extended weekend (Whit Sunday and Whit Monday) and consumption was lower than usual (the previous Sunday the maximum consumption was 64,427 GWh).
The financial consequences of this production are another matter. The article explained that the price dropped during that 15 minutes below €50 per MWh, seemingly suggesting that it was a good thing. Again, this didn’t make much sense, so let’s look at the Agorameter data:
The price of electricity that day was well below €50/MWh the whole day (maximum price was €24.28/MWh). However, the price around and after that glorious moment was negative for more than four hours! Lowest value was €-35.02/MWh. In other articles I found that this €57/MWh (in negative) was the bottom spot price at that day, so this was the price that Germany had to PAY to its (commercial and export) customers to consume electricity.
To close, I would seriously doubt that the Germany economy was running on wind and solar last Sunday, certainly not entirely. It doesn’t show in the data. If it was true that production of green electricity matched consumption, it probably would be for a very, very brief moment.
Production by renewable sources didn’t match the consumption on May 15 in Germany. As suspected, it has indeed to do with the delay in showing some of the data in the graph. You can read it on the Agora site: Why there was not 100 percent power consumption from renewable energies on Whit Sunday after all.