The Second Transformer at Waratah BESS Is Operational (for Testing)

Key Takeaways

• HVT2 returned to service, now in testing phase
• PASA availability shows 700 MW capacity, but only 350 MW active
• Third transformer (HVT3) remains offline, repair ongoing
• Full three‑transformer operation targeted by end‑2026
• Battery continues delivering 350 MW under SIPS

Pulse Analysis

Waratah’s 350‑MW battery storage project is a cornerstone of South Australia’s transition to a low‑carbon grid, providing fast‑response ancillary services and firming intermittent wind and solar output. The facility relies on three high‑voltage transformers to move large power blocks in and out of the network; any outage reduces its ability to meet market demand and can affect price volatility. After a failure in late 2025 that sidelined one transformer, operators have been methodically restoring capacity while avoiding the aggressive ramping that precipitated the earlier incident.

The recent return of the second transformer (HVT2) to service marks a critical step forward. Although the National Energy Market’s PASA data now lists a 700‑MW availability, the battery’s commercial dispatch remains capped at 350 MW until HVT2 completes rigorous performance testing. This cautious approach prevents premature exposure to market stress while still allowing the unit to appear in market bids, offering transparency to traders without inflating actual supply. Observers note that the ramp‑rate during the testing window appears more conservative than the October 2025 event, suggesting lessons learned are being applied.

Looking ahead, the third transformer (HVT3) is still under repair, with full three‑transformer functionality projected for late 2026. Achieving that milestone will double the battery’s effective capacity, reinforcing South Australia’s ability to absorb renewable generation and provide grid‑balancing services during peak demand. Market participants will likely adjust their bidding strategies as the battery’s firm capacity expands, potentially smoothing price spikes and supporting the broader rollout of large‑scale storage across the NEM.