UTS 19 May 2009

UTS claim

Contact Energy submitted a claim that a UTS occurred on 19 May 2009.

The claim alleged there were issues in processes and calculations for a high spring washer price situation in the North Island, leading to elevated final prices.

Our investigation

Contact Energy lodged a claim that a UTS occurred during trading period 16 on 19 May 2009.

The claim alleged there was limited explanation on how final prices of up to $6268/MWh were calculated and whether the modelled spring washer solution for these high prices was consistent with actual transmission flows.

We ordered the delay of final prices for the day while the claim was investigated.

Our investigation found the prices calculated for 19 May were correct and that the pricing process was also performed correctly. The system operator also confirmed that the modelling data used was in accordance with the latest grid owner offers.

Spring washers are valid solutions from the scheduling, pricing and dispatch model and reflect the laws of physics on power sharing through circuits.

Our decision

We found that a UTS did not occur as the situation did not threaten the wholesale market for electricity.