Massive grid upgrade required for nuclear option

Asma Aziz, Edith Cowan University

Keeping the lights on in Australia is a complex task. Enough capacity must be ensured everywhere in the country, at every moment. Surplus in one location won’t solve shortages in another, unless we have the transmission infrastructure to transmit electricity between them.

The transmission network largely consists of high-voltage lines and towers, as well as transformers which transfer electrical energy from one circuit to another.

Australia’s transmission network is one of the oldest and longest in the world. As coal stations close and more renewable energy is built, the task of upgrading the system becomes even more pressing. So formidable is the challenge, it’s one of the biggest roadblocks Australia faces in reaching its crucial goal of net-zero emissions by 2050.

The Coalition’s plan for seven nuclear energy plants in Australia further complicates the task. A clear policy direction for Australia’s electricity system is urgently needed.

Lots of work to do

In technical terms, transmission congestion occurs when an element on the network, such as a high-voltage power line or transformer, reaches capacity and cannot carry more electricity.

Think of it as like traffic in a city. During rush hour, bottlenecks occur when there are more vehicles than the roads can handle. During times of peak electricity demand, electricity lines and transformers can also reach their limits. Exceeding the limits of the network can damage equipment and lead to power outages.

Between now and 2050, Australia’s electricity consumption will surge. We’ll need to draw power from increasingly diverse and far-flung sources. Coal power plants, typically located near large population centres, will close. Energy generation from solar and wind farms, usually located in regional and remote areas, will increase.

Importantly, we must make the distinction between electricity capacity and whether that electricity is “dispatchable”, or can be released on demand. That’s one reason why we need new transmission lines – to move electricity around the system as needed. The sooner we can build this capability, the quicker and cheaper our energy transition will be.

So far this decade, 490 kilometres of new transmission lines have reportedly been added to the National Electricity Market, which serves the east coast and South Australia. A further 2,090 km of transmission lines are progressing from the planning phase to the construction phase.

There’s still a lot of work to do: around 10,000 km of new transmission lines is needed by 2050. Western Australia’s main electricity network also needs more than 4,000 km of new high-capacity transmission lines.

A looming problem

The network’s ability to carry electricity is influenced by several factors. They include weather conditions, patterns of electricity generation and demand, the capacity of individual elements such as transmission lines and transformers, and their reliability.

Congested transmission can cause fluctuations in power prices. If cheaper electricity cannot be transported to where it’s needed, more expensive generators are dispatched to meet demand. This increases the price of electricity for both energy retailers and consumers. It can also lead to higher prices in some areas than others and poses financial risks for energy providers.

Transmission congestion in Australia is a looming problem. For example, South Australian transmission company ElectraNet forecasts rising congestion on that state’s network due to planned expansions of electricity generators, peaking in the late 2020s and 2030s.

What’s more, planning studies have identified ageing assets in Queensland’s transmission network, requiring new routes to manage constraints and ensure reliable supply.

Where does nuclear fit in?

All this has implications for the Coalition’s nuclear plan, if it comes to fruition.

The CSIRO and others say a nuclear power plant of any size would not be operational in Australia until after 2040.

If transmission lines are congested at that future point, nuclear power plants may not be able to send all their electricity to the grid.

Nuclear plants are expensive to build and run. But they typically generate electricity continuously, helping to offset these costs. If the plants can’t feed into the grid, or can’t sell their electricity at competitive prices, they may lose revenue and struggle to cover their costs, affecting their long-term viability.

The continuous high output of nuclear plants also helps them run efficiently. Frequently adjusting energy output leads to more wear, lower efficiency and reduced energy production over time.

Constraining nuclear output can have broader repercussions, too. In France, for instance, nuclear output is at a 30-year low, forcing the country to import electricity and prepare for potential blackouts. The reactors are offline for maintenance, not due to transmission issues. But the example highlights the consequences when nuclear energy is taken out of the mix for any reason.

Clarity is needed

Finally, the increasing share of renewable energy in our electricity grid means there’s no guarantee transmission capacity will be available for nuclear energy.

As South Australia’s energy minister Tom Koutsantonis noted on X, this poses challenges for the Coalition’s plan to build a nuclear plant at the site of an old coal station at Port Augusta and use existing transmission infrastructure:

The myth that a nuclear reactor could just plug into the old Pt Augusta coal power station transmission lines is not true. The transmission lines are already nearly full from new renewables. In truth, a nuclear reactor at Pt Augusta would need new transmission lines, the exact thing the LNP are complaining about.

So what’s the upshot of all this? Transmission infrastructure is a thorny policy problem, and divergent views among policymakers about energy policy only add to the challenges.

A clear direction on the future of Australia’s electricity grid, including transmission infrastructure, is essential. Without it, the energy transition will be slower and more expensive.

Asma Aziz, Senior Lecturer in Power Engineering, Edith Cowan University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The Conversation
The Conversation
The Conversation Australia and New Zealand is a unique collaboration between academics and journalists that is the world’s leading publisher of research-based news and analysis.


    • Stevo,
      Irrespective of whether the Future is Renewables or Nuclear, there still need to be a Massive Upgrading of the existing Power Distribution Network, as there are major section that are almost at FULL Capacity NOW.
      Therefore there will be an extension/expansion of the “very ugly HT power lines crisscrossing the landscape” !!!

      • The upgrades are already being done by power generators and in a lot of areas not with HT pylons but with underground cabling. The monstrosities of fields of solar panels or wind turbines are a much bigger eyesore than electricity pylons.
        Nuclear is the way to go.

  1. With no back ups for no wind days and no sun days, I can’t wait for the politicians to be proved terribly wrong and we all get blackouts. Solar and wind need more than battery backups – how long would a battery provide power for Sydney or Melbourne – half a day? We need instant switch on backups which are basically gas fired generators. Solar and wind probably need even more power grid upgrades because the solar will a long way from cities in beautiful sunny inland and wind will be offshore and also requiring major transmission line upgrades.

  2. The difference between the coalition’s and the Labor/Green policies is that the coalition proposes a mix of solutions, including both Nuclear as well as “Renewables” (read intermittents). Labor/Greens however exclude nuclear.

    One has to accept that BOTH approaches will require upgrading the grid as times goes on. But it is also obvious that excluding nuclear will undoubtably require a greater scale of grid upgrade AND a less reliable supply of electricity with a greater likelihood of brown-outs and black-outs.

  3. The moment the Coalition announced the nuclear option, the anti-Coalition cohort started looking for every way that they could to discredit it. Nuclear promises to more than meet the Net Zero target before the agreed dates.
    Unfortunately there are too many vested interests in politics (mainly supporting the Left) who could see that they would lose their incomes and relevance if the need for renewables was negated.
    As the proposed locations for the nuclear power stations is at present aggregation connectors, there would be no need for additional HT connections. Simply the normal upgrades that would’ve been scheduled anyway.
    It is the integration of thousands of wind and solar installations that are sprinkled across the country side like a dogs breakfast that are creating the needs for extensive changes to the HT system.
    Used intelligently integrated nuclear power stations would smooth the power management and dispense with the need for the wind towers that are being built adjacent to and in National Parks with tens of thousands of new HT lines ripping clearways through old growth forests and solar farms that are covering previously productive farming land with millions of panels. The true scale of this damage to our natural heritage is kept out of site of the general public while the cost will be borne for generations.
    The true environmental cost comparisons between renewables and nuclear seem to over look that the nuclear power station would be powering 24 hours a day for over 60 years. All of the wind turbines and solar farms are on contracted operational lives of between 20 and 25 years. At which point all will need to be deconstructed and replaced.
    The CSIRO Study on the costs comparisons that showed nuclear as grossly expensive is deeply flawed with many errors and incorrect assumptions.
    Objective scientists have questioned the entire rationale of Net Zero within Australia and find that it will have no benefit to Australia in either economic, social or environmental effects.

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