Key Events Timeline – NSW Friday 10 Feb 2017

A timeline of key market events & announcements in NSW last Friday, now that the dust has settled somewhat. The reasons for and full details of some of these events are not yet fully clear. No doubt more information will emerge in coming days.

Times are given in the format “Market Time (Sydney Time)” to reduce confusion. Market Time is Australian Eastern Standard Time and Sydney Time is one hour later because of daylight saving.

• Thu 17:15 (6:15pm) AEMO issues “Predispatch PASA” LOR (Lack of Reserve) notices showing the following forecast Lack of Reserve conditions in NSW for Friday. AEMO’s maximum Scheduled Demand forecasts for Friday afternoon at 14,581 MW (half hourly basis).

LOR1 : 11:30 (12:30pm) to 13:30 (2:30pm)

LOR2: 13:00 (2:00pm) to 15:00 (4:00pm)

LOR3: 15:00 (4:00pm) to 17:30 (6:30pm) : maximum deficit  –419 MW

LOR2: 17:30 (6:30pm) to 19:00 (8:00pm)

LOR1: 19:00 (8:00pm) to 20:30 (9:30pm)

“Reserve” is the surplus of available supply (online generation and available interconnector flows) over demand. LOR3 means negative reserve ie insufficient supply to meet demand. “Actual LOR3” would represent load shedding (as occurred in South Australia on Wednesday 8 Feb). LOR2 means that one defined contingency – typically loss of the largest generator in the region – would result in negative reserve, ie LOR3. LOR1 effectively means that two successive contingencies – ie loss of largest two generators – would result in negative reserve.

• Fri 10:36 (11:36am) AEMO updates LOR notices for the afternoon / evening of Friday. Maximum Scheduled Demand forecasts steady at 14,587 MW:

LOR1 : 12:00 (1:00pm) to 14:30 (3:30pm)

LOR2: 14:30 (3:30pm) to 16:00 (5:00pm)

LOR3: 16:00 (5:00pm) to 17:00 (6:00pm) : maximum deficit  –77 MW

LOR2: 17:00 (6:00pm) to 18:30 (7:30pm)

LOR1: 18:30 (7:30pm) to 20:30 (9:30pm)

This represents some forecast easing of the situation  – in particular the negative reserve / LOR3 window is now one hour with a minimum deficit of 77 MW vs two and half hours previously with a deficit of 419 MW.

• 11:30 (12:30pm) AEMO’s maximum Scheduled Demand forecasts now peaking at 14,735 MW for the half hour ending 16:30 (5:30pm).
• 13:00 (2:00pm) AEMO announces Actual LOR1 condition commencing from 12:50 (1:50pm) forecast to remain until 20:00 (9pm), broadly in line with the morning update. Maximum Scheduled Demand forecast unchanged.
• 13:16 (2:16pm)  AEMO updates forecast LOR2 conditions as:

LOR2: 14:30 (3:30pm) to 16:00 (5:00pm) and 17:00 (6:00pm) to 18:30 (7:30pm) – (effectively no change on morning update)

AEMO determines that the latest time at which it would need to intervene to increase system reserve would be 14:30 (3:30pm)

• 13:28 (2:28pm) AEMO updates forecast LOR3 condition as:

LOR3: 16:00 (5:00pm) to 17:00 (6:00pm) : maximum deficit  –189 MW

– A slight worsening of the forecast reserve deficit

• ~14:00 (3:00pm) Press reports appear online indicating that electricity supplier AGL has issued a curtailment notice to the Tomago aluminium smelter for rolling supply interruptions at each of its three potlines (~310 MW of load each) for successive periods of up to 1 hour and 15 minutes, ie 3 hours and 45 minutes in total, commencing from 14:45 (3:45pm). A later media statement from AGL provides further details of the contractual arrangement relied upon by AGL in issuing this notice.
• ~14:05 (3:05pm) NSW demand which had been growing strongly through the day in line with or above AEMO’s forecasts, begins to flatten / grow more slowly, falling below AEMO forecasts (shown below in a view from ez2view’s Forecast Convergence widget). Actual demand for the day ultimately peaked at around 14,000 MW (slightly lower on a half hourly basis, slightly higher on a 5 minute basis), but significantly lower than the original maximum forecast:

• 14:35 (3:35pm) Colongra open cycle gas turbine power station located between Gosford and Newcastle, owned by Snowy Hydro, commences unloading from output of 644 MW, in accordance with bid prices & volumes submitted earlier in the day. Output reduces to zero by 15:15 (4:15pm). Snowy’s Tumut 3 hydro station commences ramping up from 640 MW towards 1,700 MW. Spot price in NSW has remained below $300-$340/MWh through the day so far.
• 15:35-16:10 (4:35-5:10pm) several dispatch price spikes to 4-digit levels as demand continues to grow, highest $7,565/MWh.
• 16:19 (5:19pm) AEMO cancels LOR3 condition previously forecast for 17:00 (6:00pm) to 18:00 (7:00pm).
• 16:20-16:25 (5:20-5:25pm) EnergyAustralia’s Tallawarra gas-fired combined cycle power station located south of Sydney on Lake Illawarra trips from near full load of 408 MW to zero output due to a plant failure / forced outage. Dispatch price spikes to $14,000/MWh essentially remaining at that level until 18:10 (7:10pm). Highlighted below is EnergyAustralia’s capacity rebid entered at 16:26 (5:26pm) shown in a view from ez2view’s Bids & Offers tool:

• 16:30 (5:30pm) Import flows and scheduled targets on interconnectors supplying NSW from Queensland and Victoria commence exceeding system security constraint limits, remaining outside these limits by up to ~800 MW until 17:10 (6:10pm).
• 16:34-16:54 (5:34-5:54pm) Colongra makes a rapid series of rebids, initially showing the entire station as unavailable for the rest of the day, then reducing the period of unavailability until 17:30 (6:30pm), then showing 3 units as available from 17:00 (6:00pm) – the resulting availability profile is shown below in a further ez2view screenshot. Information in the rebid reasons given for these and later availability changes indicate that the station may have been preparing to switch between gas and liquid-fuel firing at this time. The location of Colongra on the gas supply network limits the amount of pipeline gas that the station can draw in a day to the equivalent of 5 hours running at full capacity:

• 16:44 (5:44pm) AEMO declares Actual LOR2 condition for the period 16:35 (5:35pm) to 17:30 (6:30pm), states that minimum forecast reserve level is 675 MW.
• ~17:00-17:10 (6:00pm – 6:10pm) Large fall in 5 minute demands seen in NSW, ~600 MW. Interconnector flows return within security limits.
• 17:20 (6:20pm) AEMO announces that an Actual LOR3 condition has existed from 16:50 (5:50pm), forecast to remain until 18:00 (7:00pm) . “Actual LOR3” means actual interruption of customer load as stated in AEMO’s notice, however unlike South Australia two days earlier there was no general rotational load shedding, so presumably the load interrupted was that at Tomago

• 17:15 – 17:40 (6:15pm – 6:40pm) Colongra gas turbines recommence production, reaching maximum output of 480 MW (one out of four units not running).
• 17:43 (6:43pm) AEMO issues market notice indicating that it has Directed a Market Participant, Direction issued at 16:58 (5:58pm) and expected to be in place until 18:00 (7:00pm)
• 18:10-18:15 (7:10-7:15pm) Dispatch price falls from $14,000/MWh to ~$100/MWh
• 18:12 (7:12pm) AEMO announces cancellation of Direction from 18:01 (7:01pm)
• 18:26 (7:26pm) AEMO announces cancellation of Actual LOR3 effective from 18:05 (7:05pm)

The final chart below summarises graphically movements in some of the key market data referred to in this timeline, with references to a number of the events listed above: