We know of people on the mainland who see Tasmania’s role in the NEM as nothing more than an alternating load or generation at the end of the Basslink subsea DC interconnector, but we have a number of clients on the island so (for this and other reasons) do take an interest in what’s happening there.
We noticed this morning a significant drop in demand starting in the 1:05 dispatch interval this morning (so 2:05 Tassie time) – as can be seen here in this snapshot from a beta of the new NEM-Watch v10:
As shown, the Basslink interconnector tripped this morning around 1:55am Tassie time. Because Basslink was importing to Tasmania at the time, and because night-time Tasmanian demand was already low – hence local spinning reserve capability was low, this triggered the tripping of a number of approximately 600MW of load (industrial loads and probably residential load as well).
AEMO published 3 Market Notices early this morning (highlighted above in NEM-Watch, and opened below) that explain further:
As shown in the Market Notices highlighted, AEMO had to intervene in the market to direct a participant to maintain the system in a stable operating state (there’s not many participants in Tasmania, so you can probably guess who).