AEMO High NSW Prices and Negative Queensland Prices – 10 August 2010
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This report has been prepared to explain the unusual market outcomes and circumstances that led to high energy prices in New South Wales and negative energy prices in Queensland on Tuesday 10 August 2010.
New South Wales experienced energy prices of $6266.50 per MWh and $5738.78 per MWh for trading intervals (TIs) ending 0830 and 0900 hrs respectively, and Queensland experienced energy prices of -$488.22 per MWh and -$326.88 per MWh respectively in the same TIs.
Wallerawang Power Station Unit 7 (WW7) in New South Wales was being returned to service with the Marulan–Mt Piper (36) 330kV transmission line out of service for construction work. Returning the unit to service required short notice system reconfiguration switching, resulting in lower thermal ratings for the Mt Piper–Wallerawang (70 and 71) 330kV transmission lines. An outage and a system normal constraint equation both violated for 4 dispatch intervals (DIs) due to the lower line ratings, setting the NSW 5-minute dispatch prices at the market price cap (MPC) of $12,500 per MWh.
Immediately following the first high price in New South Wales, a number of rebids by Generators in New South Wales resulted in approximately 11,000 MW of capacity being offered at negative prices, with high ramp-up and low ramp-down rates of change. This resulted in a rapid increase in the amount of generation dispatched in New South Wales, reducing imports from Queensland. With excess generation in Queensland, an energy offer of -$1,000 per MWh was marginal during the four over-constrained DIs, resulting in negative Queensland prices for the two TIs in question.
For further information on this document, please contact: Brian Nelson, Electricity Market Performance.
Market Event Report : High NSW Prices and Negative Queensland Prices – 10 August 2010
06 Sep 2010 | filename: 0180-0007.pdf