~28 Years of History for the VIC-SA Interconnector, in One Chart

Key Takeaways

• Early 2025 saw capacity jump with PEC Stage 1 testing.
• 1999‑2017: VIC net exported ~44 MW to SA.
• 2017‑2020: SA net exported ~49 MW to VIC.
• 2021‑2026: VIC net exported ~44 MW, reversing prior trend.
• 57% months SA price spikes >$1,000 (≈$660 USD) over VIC.

Pulse Analysis

The Victorian‑South Australian (VIC‑SA) interconnector, often referred to as Heywood, has been a barometer of Australia’s evolving electricity market for nearly three decades. Early data (1999‑2017) show a steady north‑to‑south power flow, with Victoria supplying roughly 44 MW on average to South Australia. This pattern underpinned regional price convergence and helped balance intermittent renewable output in both states. The subsequent 2017‑2020 period marked a pronounced reversal, as South Australia became a net exporter of about 49 MW, driven by the closure of the Hazelwood coal plant and a surge in SA’s solar and wind capacity.

A pivotal shift arrived with Project Energy Connect (PEC) Stage 1, which temporarily lifted the interconnector’s transfer limit in October 2024 and formally entered operation in January 2025. This capacity jump enabled higher bidirectional flows, smoothing price differentials that historically spiked—57 % of months saw South Australian prices exceed Victorian prices by more than $1,000/MWh (≈$660 USD), with 30 % of those spikes surpassing $10,000/MWh (≈$6,600 USD). The enhanced bandwidth also provided a safety valve during extreme events, allowing surplus renewable generation to move where needed and reducing the frequency of extreme price spikes.

Looking ahead, the forthcoming PEC Stage 2 promises a permanent uplift in transfer capability, positioning the VIC‑SA corridor as a critical conduit for the National Electricity Market’s low‑carbon transition. Greater capacity will facilitate deeper renewable penetration, improve grid resilience, and create new arbitrage opportunities for traders. Stakeholders—from generators to retailers—must monitor these developments, as the interconnector’s evolving dynamics will shape investment decisions, market pricing, and the broader strategy for Australian energy security.