Responding to peer comments:

This is pretty clearly NordPool's fuckup. There's no way in hell this bid should have gone thru without human review. Seems clear that their UI is to some degree - in some critical spot - fragile, user-hostile, ill-designed.

You can say that in analogous cases, finance firms have been put out of business by bad bids caused by slipped fingers. Granted. But in this case you're throwing a wrench into a power grid, with the potential to cause a system disruption, in winter no less.