Adding to the complexities of the current supply-demand balance in NSW, this afternoon we saw Vales Point unit 6 trip offline via a ‘Notification’ (alert) in ez2view:
From this we see that the unit tripped from 190MW (FinalMW at 14:15) to 0MW (FinalMW at 14:20 NEM time).
Recent run of performance of Vales Point unit 6
Remember that this unit was not the Vales Point unit that tripped early on Wednesday morning 8th May, but rather it’s the unit that’s been struggling along with only partial availability for a number of days. We can see some of the details here in this snapshot from ‘Bids & Offers’ widget in ez2view:
See many of the rebid reasons referencing ‘PA Fan Limitations’:
1) my (quite aged) power station experience revolved around the descriptors of:
(a) FD (Forced Draft), upstream of the boiler; and
(b) ID (Induced Draft) fans, downstream of the boiler.
2) but I believe a PA Fan (Primary Air Fan) is similar in purpose to the FD Fan, just different in some details I’m not familiar with.
… so a limitation in PA Fan ability would clearly limit the unit capacity. Whether this was the reason for the unit trip, or not, is unknown at this point.
Has it changed the prognosis for Monday morning?
We’d noted earlier that ‘AEMO ‘forecast LOR2’ for Monday morning 20th May 2024 currently growing tighter’ … I wondered whether the trip of VP6 had propagated into a discount on Available Generation capacity forecast for Monday morning:
But, as highlighted in the zoomed-in ‘Forecast Convergence’ widget snapshot at 17:10 today (i.e. almost 3 hours after the trip) that that’s currently not the case.
ID fans are downstream and maintain a small negative pressure in the boiler, precipitators/baghouses to keep things inside. FD fans provide the bulk of the mass of hot (ish) combustion air to the furnace to ensure complete combustion occurs. Generally, controls to around 3% residual oxygen in flue gas stream to prevent CO formation. PA fans provide hot air to the mills to dry pulverized coal and transport the milled coal from the mills to the burners. No PA fans = no fuel.