[cratermoon]

How much money was or will be lost as a result of this? Is this a Knight Capital -level error?

[fulafel]

Going by the trade value:

-203.40 per MWh, 5787 MW for 24h, 203.40578724 = 28M € - so about 5% of Knight Capital $440M

Of course this may not be all, as they still have to buy the electricity from somewhere that they are selling for negative price...