Reasonability check is a on-best effort service provided by Nord Pool where submitted curve orders are compared with previous trading days. A substantial deviation based on the reference day price will flag the submitted curve order, thus making it easier to identify erroneous bids. A similar functionality is also available on the Nord Pool Operator UI side. 

Members will be notified directly in the Trading UI if their orders deviate from previous days. In case a curve order does not pass the reasonability check, it will be flagged and shown with a yellow bar. From the curve order detail view, participants will have access to view the values from the Reasonability check calculation for the flagged hours.  

Please note that the responsibility to submit correct orders lies with the members and that unintentional errors or ignorance can be seen as market manipulation under REMIT Article 5 (or NEM §5-4 in Norway). Reasonability check tool in Trading UI will hopefully help to identify and correct erroneous bids.


Flagged order

  1. When an order is flagged, it is highlighted (in yellow) in the Trading UI. The member can “approve” the order from this view, if wanted.
    Note that the approval has nothing to do with the order being accepted in the orderbook or not. Orders market in yellow are part of the orderbook, it just highlights that it deviates from the volume at reference price.


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  1. When the member clicks the portfolio to see the order detail view, the flagged hour(s) are shown in yellow. The member can hover over the flagged hour to see the reference day, reference price and the volume deviation. The same volume deviation is also shown in the Operator UI on Nord Pool side. 


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  1. When a flagged order is approved in the Trading UI, the yellow marking will disappear. In addition, the order will also be marked as approved for Nord Pool Operators. 


        d. Tick of “approved by” in the drop-down menu to view who approved your order.

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Validation rules

Current reasonability check consists of three chained calculations for all time periods of a curve order in order to pass the validation. An order will be flagged if none of the three calculations are passed. The calculations executed are following (in order):

  1. Absolute volume difference 

  2. Percentage difference 

  3. Standard Deviation


Any curve order change (new or update to existing) will trigger an asynchronous calculation of the reasonability results. For all calculation methods, a reference day is used to define prices (and orders for some calculation methods) to be used as part of calculations to see if there is significant difference in the order compared to the historical orders. Reference day is defined with following principles:

  • If Delivery Day is a weekday, the previous weekday with results is used as reference day price.
    • Example: For delivery day Tuesday (trading day Monday), results for delivery day Monday (trading day Sunday) is used as reference day price.


  • If Delivery Day is a weekend day, the previous weekend day with results is used as reference day price.
    • Example: For delivery day Sunday (trading day Saturday), results for delivery day Saturday (trading day Friday) is used as reference day price. 


NOTE: There is no established logic to handle bank holidays. This may lead to more orders being flagged by reasonability check tool due the reference orders and prices corresponding with “normal” workdays rather than weekend or public holidays. 


Important remark: Reasonability check tool does not prevent any orders from being part of the auction. It is meant as a tool to help distinguish anomalies compared to normal behavior in member bids, so that members can adjust/remove their bids before GCT if needed.

Disable/Enable Reasonability check

The Reasonability check tool can be disabled/enabled from the user Settings. By default, it is enabled. 

  • Click your user name to open the Settings
  • In Settings, click to disable/enable