NEM market conduct monitor
Price events where bidding may warrant a closer look. A flag is a prompt for review, not a finding that a rule was broken.
Three kinds of indicator:
- Rule-based (National Electricity Rules 3.8.22 and 3.8.22A): late rebids that move capacity to higher prices, availability cuts with no matching cut in PASA (physical) availability, and rebid reasons with no verifiable detail.
- Market power, lawful but monitored by the AER: cheap capacity withdrawn against the day-ahead offer, and capacity priced at $5,000/MWh or more while the group was pivotal.
- Context: the price event itself. A spike alone is not evidence of anything.
An event is a run of 5-minute intervals in one region where the price spiked, stayed high, reached double its 30-minute-ahead forecast or hit the floor, or where an FCAS price spiked. The method notes give the thresholds. Groups are the companies holding each unit's trading rights.
Last 12 months
- price events
- reached $5,000/MWh
- reached double the 30-minute-ahead forecast
- energy cost in event intervals
Price events by month, and how many the forecast missed
A price the P5MIN forecast did not see 30 minutes earlier means something changed late: a trip, a demand surprise or a late rebid.
Rebids against their own 7-day average, by the day's maximum price
Rebidding rises with price, because rebidding when forecasts change is allowed and routine. What stands out is one group rebidding far above its own norm on a spike day.
Price events, last 12 months
Newest first. Click a day to load it in the panels below the calendar.
One day at a time
Click a day in the calendar, or a day in the price event table above, and every panel below the calendar shows that day in the selected region. Rebid counts cover scheduled coal, gas, hydro and liquid-fuel units.
Daily maximum price, last 12 months
The redder the day, the higher its maximum price. A spike on its own proves nothing, so click a day to see who rebid and what they offered.
Selected day
- click the calendar to change
- maximum price
- region of the maximum
- minutes at $300/MWh or more
- rebids
- the previous 7-day average
Rebids on the selected day against each group's previous 7-day average
Most groups rebid more on a dear day. A group far above its own average, rebidding in the half hour before the price rose, is the one to read in the reasons table.
Cheap capacity withdrawn is MW offered at $300/MWh or less in the day-ahead offer, minus the same in the bid in effect; late rebid shift compares with the bid in effect 30 minutes earlier. Pivotal share is the share of the day's $300/MWh intervals in which demand could not be met without the group. Review needs the group pivotal, 100 MW cleared, capacity withheld or priced at $5,000/MWh, and a rule-based flag; Watch is any single flag.
Conduct indicators on the selected day
Review rows combine market power (pivotal, with capacity held back or priced at $5,000/MWh) with a rule-based flag. Faults, fuel limits and forecast changes are legitimate reasons, so read the rebid reasons before drawing a conclusion.
Rebid reasons on the selected day
Each rebid must carry a brief, verifiable and specific reason (NER 3.8.22(c)). Reasons with no time, MW or price, and bursts of rebids just before the price rose, deserve a second look.
Method and caveats
- Events: an interval counts when the price reached $5,000/MWh, held at $300/MWh or more for 30 minutes, or fell to -$900/MWh. It also counts at $1,000/MWh when that is double the P5MIN forecast made 30 minutes earlier, and when an FCAS price reached $1,000/MW. Intervals under 30 minutes apart are one event.
- Data: AEMO dispatch prices, P5MIN forecasts, dispatch unit solution, regional demand, interconnector limits, energy offers (BIDDAYOFFER, BIDOFFERPERIOD) and the bid in effect.
INTERVENTION = 0throughout. Times are NEM time (UTC+10). AEMO publishes bids the next day, so the page runs to yesterday. - Rebid counts leave out batteries, whose bidding is largely automated and would swamp the counts. Batteries, wind and solar still count in the pivotal test.
- The pivotal test compares dispatch availability plus interconnector import limits with regional demand (residual supply index below 1). It ignores network limits inside a region, so it understates market power behind local constraints.
- Offered MW are capped at MAXAVAIL, filling from band 1 up, and band prices are divided by the unit's loss factor before they are compared with $300 or $5,000/MWh.
- Hydro and battery offers price stored water or charge, so a high price or a withdrawn band from them can be an energy-management decision.
- Cheap capacity can leave the market after a plant fault, a fuel limit or a forecast change. The reasons table shows what the participant told AEMO. Whether a reason states a time, MW figure or price is a text test, not a compliance test.
- The thresholds (50 MW or 10% of day-ahead availability, 100 MW cleared, $300 and $5,000/MWh) are starting points, not regulatory limits.