The effect of this was that for the Tauranga node and trading period 36 a relatively ‘normal’ dispatch price of $68.88/MWh was followed by a five minute price (averaged over the half hour) of $54,901.85/MWh and a provisional price of $8,242.67/MWh.

The Electricity Commission Board considered the circumstances and the claim and found that because of a Transpower error in failing to remove a constraint when it had advised participants that it would, an undesirable trading situation existed during the trading period in respect of the Tauranga node. Following consultation with affected participants, the Commission directed the pricing manager to calculate the prices for trading period 36 on the basis that the Tauranga Constraint was removed.