German wind + solar push power prices way down on Sunday
Based on our best estimate, Germany managed to get 34 percent of its electricity from wind and solar over a 24-hour period on Sunday – measured in gigawatt-hours, not gigawatts. Prices on the exchange were quite negative.
We often read of German records in solar power production, but these are often expressed in peaks – the greatest amount of solar generated at a single time. On the date in question behind the link in the previous sentence, Germany got 33.5 percent of its power from solar and wind combined, almost all of which was solar that day (Sunday, July 21).
There is another way of expressing that: watt-hours instead of watts. Then, you are not talking about peak production at any one moment, but the share of power over a given timeframe. For instance, Germany posted record solar power production in July at 5.1 TWh – still less than a fifth of the conventional power generated.
On Sunday, we seem to have reached another near-record peak of 34 percent wind + solar, with the absolute record possibly being 46 percent wind + solar on December 31, 2012 (almost all of which, naturally, was wind power).
Unfortunately, in looking to see what the actual record is in terms of watt-hours, we found a bit of a gap. Bruno Burger’s popular PDF lists peak production by the watt, with no indication of maximum watt-hours for combined wind + solar on a daily basis.
Our colleague Bernard Chabot produced this overview of solar and wind power production on Sunday:
We can see what the impact of all of that wind and solar power was on demand for conventional power in this chart from the EEX:
For most of the afternoon, conventional generation fell below 24 gigawatts. And if we look at the EPEX for prices, we see that they fell through the basement:
The downturn also affected the Swiss and French exchanges, both of which posted clearly negative power prices on Sunday (see the EPEX website), but closer to 5 PM – and not quite as low as in Germany.
The situation is unfortunate for conventional power plants that do not ramp down easily (mainly nuclear and coal), which then try to pay people to consume. Such firms are seeing their profitability hit hard, and another chart in Burger's collection shows us why even proponents of renewable should care. On December 19, just 12 days before wind + solar made up 46 percent of total demand, German wind power production reached its low for the year (see chart 30 in the PDF linked to above). Clearly, we will need dispatchable capacity in the winter. (Craig Morris)