The wire Bavaria buried

The Windiest Day Ever Recorded

On 21 December 2023, storm Zoltan crossed Germany, and the country's wind fleet produced 1.112 terawatt-hours of electricity in a single day. Not a record for the month, or the winter, or the decade: the windiest day ever recorded in Germany, on Fraunhofer ISE's tally. Output passed 50 GW, and the federal maritime agency logged two severe North Sea storm surges in the space of a day and a half. December 2023 closed with 72 hours of negative day-ahead prices and six consecutive days on which the price fell below zero at some point.

What that day cost to manage is not a number this editorial can give you: Germany's regulator publishes congestion figures quarterly and annually, not daily. What can be said is that a day like Zoltan produces two entirely different and equally official accounts of itself, and the gap between them is the subject of everything that follows.

In the first account, the one the market keeps, Germany is a copper plate. The day-ahead auction clears the German–Luxembourg bidding zone at one price for every hour, as though any generator anywhere in Germany can serve any load anywhere in Germany. The market does not know the grid exists.