Australia's National Electricity Market (NEM) is sitting on an enormous backlog of energy projects. More than 56 GW of large-scale generation and storage capacity is in the development pipeline, including 26 GW of battery storage. That is more than twice the size of the existing operational renewables fleet. But the grid cannot absorb it. Curtailment – the forced reduction of output from solar and wind farms – has climbed sharply. By Q3 2025, total wind and solar curtailment reached roughly 3.9 TWh, or about 6 percent of potential renewable generation. The numbers tell a clear story. We are building generation and storage faster than we are upgrading the grid that connects them.

AEMO's data shows that while new renewables continue to queue for connection, grid approvals have slowed to a crawl. Only eight new projects were approved in Q3 2025, compared with more than sixty a year earlier 3. Developers are not only waiting for capacity, they are waiting for clarity. Each new solar, wind or battery project must now be modelled against every other proposal in its renewable energy zone. Connection reform has improved transparency but also introduced recursive complexity. Each adjustment triggers another cycle of stability studies and harmonic reviews.

At the same time, system strength has emerged as the quiet constraint behind many connection delays. As synchronous generation retires, new renewables must carry more of the burden for voltage and frequency stability. AEMO and the transmission network service providers (TNSPs) are still catching up, which means even projects that have technically "passed" their studies can remain stalled. The outcome is a paradox: a grid that appears underutilised but is effectively saturated.

The opportunity

Building new 500 kV transmission lines is essential for the long term, but it is slow, expensive and politically charged. In the meantime, there is untapped capacity sitting right above us.

Across the NEM, thousands of kilometres of 220 kV and 330 kV corridors still use aged ACSR conductors with temperature limits around 75 to 90 °C. By replacing these with modern high-temperature low-sag (HTLS) conductors, such as ACSS or ACCC, we can increase the current-carrying capacity by 40 to 100 percent 4.

When paired with Dynamic Line Rating (DLR) systems – sensors that measure temperature, wind and sag in real time – operators can safely gain another 10 to 20 percent headroom under favourable conditions 5.

This approach is already proven overseas. In Texas, ERCOT has upgraded hundreds of kilometres of 345 kV lines with higher-capacity conductors, unlocking multiple gigawatts of extra transfer capability without building new easements. In Europe, transmission operators use DLR to match network capacity to weather conditions, turning wind from a constraint into an enabler. Australia can do the same, and do it fast.

The engineering reality

Reconductoring may sound simple, but it is technically intricate. It starts with tension tables, pull-through spans, conductor creep and sag control. Each degree of thermal expansion must be accounted for.

Running a line hotter means fittings and insulators must tolerate higher temperatures, clamps must maintain tension, and towers must withstand added load. The upgrade process typically involves:

• Installing new conductors on existing towers using live-line or planned outage methods
• Verifying clearances and sag at maximum temperature and load
• Upgrading fittings, dampers and joints to handle heat and vibration
• Adjusting relay and protection settings within SCADA and energy management systems

It is engineering work of precision and coordination, but without the hardest part of new transmission projects: fighting for land and community acceptance.

The systems view

The current Regulatory Investment Test for Transmission (RIT-T) framework favours large, new transmission projects over incremental upgrades. Smaller works like reconductoring or DLR often fall below formal review thresholds. They deliver high benefit-cost ratios but struggle for visibility.

This bias toward greenfield infrastructure leaves flexibility on the table. If just a small portion of the investment planned for new transmission was redirected to reconductoring and line-rating upgrades, the NEM could unlock several gigawatts of additional transfer capacity in the near term, within the corridors we already have.

Encouragingly, momentum is building:

• Transgrid has trialled line-rating analytics on its 330 kV network
• Powerlink and ElectraNet are incorporating HTLS replacements into their asset renewal programs
• AEMO's 2025 ISP explicitly acknowledges the role of intra-regional augmentations and non-network solutions in relieving congestion while major projects proceed

The next step is a regulatory incentive mechanism that recognises these interventions as legitimate capacity investments.

What that looks like

The method is straightforward:

• Phase 1: Use DLR to release latent capacity from existing lines
• Phase 2: Identify and reconductor the most constrained spans with HTLS or ACSS
• Phase 3: Scale both upgrades corridor by corridor, creating an adaptive, staged expansion strategy

The biggest advantage is time. DLR can be rolled out in under a year. Reconductoring can typically be completed within 18 months. By contrast, new transmission lines often take eight to ten years from concept to commissioning.

The comparative frame

Other markets have demonstrated that this works at scale.

In ERCOT, ambient-adjusted line ratings have been in place for over a decade, safely boosting transfer limits during cooler or windier periods. In the United Kingdom, National Grid ESO's "Dynamic Contingency Thermal Rating" system adjusts limits in real time based on weather telemetry, adding as much as 15 percent extra transfer capacity across parts of the 400 kV system.

Each of these efforts began modestly and scaled up as confidence grew. Australia's long, radial network makes it even more suitable for this kind of targeted, staged deployment.

The technical lift

Reconductoring and DLR complement each other. One increases the thermal limit, the other adjusts the operational limit in real time.

A 100 km reconductoring project can unlock up to 600 MW of extra transfer capacity, roughly equivalent to adding a mid-sized interconnector but at a fraction of the cost and with near-zero land impact.

The social and sustainability dimension

Every new transmission line must navigate its way through landholder negotiations, biodiversity assessments, heritage protection, and local politics. Each is vital, but together they slow progress.

Reconductoring and DLR take a different path. They reuse what already exists. The towers remain. The easement remains. The landscape remains. There is no new footprint to clear, no new communities to convince.

From a sustainability standpoint, reusing infrastructure reduces embodied carbon, materials extraction, and construction waste. Each kilometre of existing line that is upgraded instead of rebuilt avoids tonnes of new steel and concrete. The lower environmental disturbance also protects local biodiversity and reduces fire risk during works.

This approach offers a rare alignment of engineering, economics and social acceptance. It builds credibility in regional communities that are tired of feeling like staging grounds for national projects. For governments and network businesses under pressure to earn social licence, it shows respect for both landscape and legacy.

And in sustainability terms, it sets a precedent: sometimes the most regenerative design is simply reusing what already stands.

Why it matters

The NEM's challenge is not just to store more energy, but to move more energy. Solar, wind and batteries are all part of the same problem if the network cannot deliver their output.

By reconductoring existing corridors and deploying DLR at scale, we can relieve the worst congestion hotspots within two years, long before new transmission arrives. It is a practical way to bring generation and storage to market sooner and reduce the curtailment that now shadows every renewable developer's business case.

If we start treating the grid as a living system rather than a fixed map of wires, upgrades like reconductoring and DLR become not stopgaps, but core infrastructure. The fastest way to build the future might be along the lines we already built.

References

1. Australian Energy Market Operator (AEMO), Generation Information – October 2025, aemo.com.au.
2. WattClarity, Solar and Wind Curtailment Analysis Q3 2025, wattclarity.com.au.
3. AEMO, Network Connections Scorecard – June 2025, PDF link.
4. Energy Networks Australia, Reconductoring with High-Temperature Low-Sag Conductors (HTLS), Technical Report 2023.
5. CIGRÉ B2.69, Real-Time Thermal Rating Systems for Overhead Lines, 2022.
6. Transgrid, Transmission Annual Planning Report (TAPR) 2025, transgrid.com.au.
7. ElectraNet & Powerlink, Future Transmission Network Development Plans 2025, electranet.com.au.