A quick first record of some FCAS volatility in TAS on Monday 14th September 2026

On Monday 14 September 2026 at 14:40, Tasmania experienced binding constraints on Regulation and Contingency Frequency Control Ancillary Services (FCAS), with both Raise and Lower services hitting the Market Price Cap. The state was running high wind output while Poatina Hydro remained on planned outage and Tungatinah Power Station was offline following fire damage. Tamar Valley CCGT was operating. The constraint event drove elevated FCAS costs across the affected services and flowed through to Frequency Keeping Payment (FPP) costs for generators in the region.

Where this fits

FCAS shortfalls under high-wind, low-hydro conditions expose a structural brittleness in the grid. Tasmania's dispatchable thermal and hydro capacity is shrinking: Tungatinah offline, Poatina unavailable, Tamar Valley gas bearing the firming load. When wind is high and hydro is constrained, the system cannot secure the synchronous inertia and regulation services needed to hold frequency during disturbances. This is a cost problem (prices to cap) and a reliability problem (binding constraints mean the grid is operating closer to its minimum safe margin). It is also a sovereignty problem: the state is leaning harder on a single gas plant for system strength at precisely the moment that firm dispatchable power is being decommissioned faster than firming alternatives are built.

What it means

As hydro availability tightens across the NEM and coal retirements accelerate, FCAS scarcity events will recur. Tasmania's experience shows that high renewables penetration alone does not solve frequency control. The grid requires either dispatchable thermal generation, committed storage, or synchronous condensers running continuously. Each costs money and takes years to build. Waiting for the market to signal the need after the fact is a strategy for price shocks and narrow reliability margins.