What is RTP (Real Time Pricing)?

Real time wholesale spot prices for energy and instantaneous reserve in each trading period are determined through the dispatch process the system operator uses to run the power system in real-time. The system operator produces 'dispatch prices' whenever they issue new dispatch instructions, typically every five minutes or so (and at least once for each 30-minute trading period).

How is it calculated and published?

Interim prices

The interim price (energy/reserve) for a trading period is the time-weighted average of the set of dispatch prices visible on WITS during that period. Any dispatch price produced by the system operator but not visible on WITS will be discarded when calculating interim prices. The interim prices are calculated and published by WITS immediately after the trading period ends.

The methodology for calculating interim prices is set out in clause 13.134A of the Code amendment.

Final prices

Price status change from interim to final happens at 14:00 on the first business day after the trading day if there is no claim of a pricing error (under clause 13.182A), or one hour after the Authority determines no pricing error has occurred or rejects a pricing error claim (under clause 13.182B). The Clearing Manager validates the interim prices and then publishes the final prices on WITS.

Pricing error

As per the code, a pricing error is defined as an error in an interim price or interim reserve price as a result of,

i.        a dispatch price or dispatch reserve price that was not made available on WITS being used to calculate the interim price or interim reserve
          price; or
ii.        the clearing manager having followed an incorrect process in calculating that interim price or interim reserve price, in contravention of this
           Code.

Pricing error claim process:

Item	Date / time	Action	Responsibility
1	D1 Trading day, end of each trading period	Calculate and publish interim prices	Clearing Manager via WITS
2	By D2 Next business day, 12:00	Submit price error claim (PEC) (Clause 13.170)	Participant and system operator may submit PEC. Clearing Manager may self-investigate
3		Receive PEC	Clearing Manager
4	By D2, 13:00	Notify participants and Authority of PEC (Clause 13.173)	Clearing Manager
5	By D2, 14:00	Make interim prices final (Prices with PEC upheld stay interim)	Clearing Manager
6	D2 - D4	Investigate PEC (Clause 13.170A)	Clearing Manager
7	By D4, COB	Notify the Authority of the result of the PEC investigation	Clearing Manager
8	By D6, COB	Decide to uphold or reject PEC	The Authority
9	As soon as practicable	Notify Clearing manager of decision	The Authority
10	As soon as practicable	Implement Authority decision	Clearing Manager

As per 13.170, an error claimant must include the following information in a written notice to the clearing manager (cm@nzx.com) no later than
1200 hours on the 1st business day following the publication of the interim prices,

1. How the error claimant has been affected by the claimed pricing error; and
2. What the basis of the pricing error claim is; and
3. Other relevant information (e.g., trading date, trading periods, participant code etc).