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Too Much Solar Power In South Australia

November 18, 2022

By Paul Homewood


Overload in Australia!





“Give us more load. And, please, switch off that rooftop solar.”

These are not instructions you hear every day, but they have been the “cri de coeur” from Australia’s Energy Market Operator this week as it battles to deal with a South Australia grid isolated by storms from the rest of the market, and one of the world’s highest penetrations of rooftop solar.

AEMO has ordered local authorities to switch off as much rooftop solar as they can, and encourage as much electricity use as possible, as it seeks to create enough “load” to give it control of a grid that fears could spin out of control if struck by another major event.

It’s quite the turnaround for the state’s solar households.

It was only a few weeks ago that SA Power Networks, which owns the local poles and wires in South Australia, was boasting of a fantastic new achievement – rooftop solar had met all local demand for more than five hours in a row in the middle of a sunny Saturday.

It was indeed, a major milestone, and a sign of things to come: This is the state with the largest share of wind and solar of any gigawatt scale grid in the world – 66 per cent of local demand in the last 12 months. And rooftop solar is a major part of that.

It is also a sign that Australia’s grid is rapidly changing from a centralised, fossil fuel based system to a renewable and increasingly distributed grid. Consumers are now producers too, and rooftop solar is chasing base-load coal and other fossil fuels out of the grid.

This week, though, SAPN had to temporarily change its tune, and has been desperately trying to cut off as much rooftop solar as it can, by sending signals over wi-fi, tripping inverters through increased voltage, and sending out public pleas for customers to switch off their rooftop solar systems, and switch on anything they can.

What has changed?

When rooftop solar reached more than 100 per cent of local demand in late October it wasn’t a problem because the grid in South Australia was connected to Victoria and could send excess power to its neighbour.

That meant there was still enough “load” in the grid, and AEMO could use a small amount of gas generation for grid security, and be comfortable in the knowledge that it had enough leg room and levers to deal with any unexpected events.

The storm that blew through South Australia last Saturday afternoon changed all of that. It tore down one transmission tower, triggered a trip in multiple circuits and “separated” the state grid from the rest of the National Electricity Market.

The state is now on its own, and large amounts of rooftop solar threaten to become more of a liability than an asset, because if rooftop solar can meet all or most of local demand, it would leave few or no levers for AEMO to pull if another major incident affects the grid.

Which is why the call went out from AEMO at the start of the week to “Give Us More Load.” It asked major energy users to turn on whatever they could during the middle of the day, and called on SAPN and the state government to switch off small solar farms.

The article tries to dismiss this problem as one caused by the storm which broke the connections to Victoria. But this is to dismiss the fundamental issue.

Intermittent energy can only be integrated in a grid where there is sufficient dispatchable power to provide stability – both to make up for shortfalls and to turn down when renewable output is high.

South Australia relies on the grid connections to Victoria and beyond to provide that stability. In 2021, only 22% of Australia’s electricity came from renewables, so the country as a whole had plenty of dispatchable power to manage the intermittency.

But in the renewable future mapped out by the Labour Government, the whole country will become like South Australia. And where then will the country offload its surplus power?

  1. ancientpopeye permalink
    November 18, 2022 3:45 pm

    Best laid plans oft go agley?

    • lefallois permalink
      November 18, 2022 3:57 pm

      Presumably, increased climate chaos will put all those widely scattered and above – ground panels, windmills, switches etc. at increased risk of damage/failure. Wll they put that into a model and decide it’s not a great idea?

    • Mr Robert Christopher permalink
      November 18, 2022 5:23 pm

      Plans? 🙂

      Written and signed off by a competent professional, in a relevant Engineering discipline?

      Like, an Engineer?

      • catweazle666 permalink
        November 18, 2022 8:24 pm

        “All engineers are good for is explaining why it can’t be done.
        If we have to wait for engineers we’ll never get anywhere”.

        Quote from Green energy enthusiast.

  2. November 18, 2022 3:58 pm

    I keep asking what will happen in the UK when we have all this wind and solar on the grid, which cannot be controlled or turned off? Power cuts, no doubt.

    • November 20, 2022 7:10 pm

      In South Australia the voltage has spiked upwards which looks like it is intended to trip out solar panels to take them offline. Yes, people might have equipment damaged but if it saves one polar bear…..

  3. GeoffB permalink
    November 18, 2022 4:02 pm

    There is not much reactive power and kinetic energy in solar, all it takes is one transmission fault/lightning strike to operate the frequency trips and the grid is gone.

    • Ray Sanders permalink
      November 20, 2022 8:30 pm

      Exactly, after all solar is a DC source (and batteries a DC store) and you really cannot get Reactive power in DC! But how many green activists know the difference between a video assistant referee (VAR) and a volt ampere reactive VAR)!

  4. John Hultquist permalink
    November 18, 2022 4:22 pm

    Where do the electrons go from a solar panel if they are not used and not sent to the grid to be used?
    I’m assuming the silicon still functions converting solar radiation to electrons. Maybe that’s not true.

    • John Hultquist permalink
      November 18, 2022 4:28 pm

      A solar panel will not turn solar energy into direct current until there is a circuit. If there is no circuit, the solar panel will just “sit there” as the photons will not be converted into electricity.

      The solar panel will get hot, but it does anyway when connected and producing electrons.
      Should have searched first.

      • iariar permalink
        November 19, 2022 9:01 am


        they still produce a voltage even if not conected, current only flows in a complete circuit. Your quote is inaccurate in theory, in practice it is right.

  5. dearieme permalink
    November 18, 2022 7:37 pm

    We used to live in South Australia – wonderful place. But such a group of pleasant, honest, rather naive people was clearly awfully vulnerable to takeover by the thumping crooks of the green dogma.

    Ah well, they voted for it.

    • Graeme No.3 permalink
      November 18, 2022 8:41 pm

      We didn’t get any choice as both major parties wanted more renewables (as in the UK).
      Some comments.
      1. The SA system has been getting less stable for years, as people try to reduce their increasing electricity bills by installing roof top solar.
      2. Even when solar was “meeting all of local demand” there were gas fired generators running, producing even more which had to be sent off via the interconnector at a loss. This was necessary to provide a stable reference voltage and frequency, without which solar (and wind) cannot start up. Some locals with home batteries as well as rooftop solar recently found that the stored power wasn’t available.
      3. When neither solar or wind is delivering SA runs on gas and diesel.
      4. In the Adelaide Hills there has been a noticeable increase in wood use for heating in recent years. Extra CO2 and a rise in the cost.
      5. The “solution” both parties are keen on is another interconnector (to NSW) so when renewables don’t deliver SA can import coal fired (at normal rates?) and when they do deliver then the excess can be sold very cheaply to them.
      6. The number of wind turbines isn’t increasing that much now – it seems that the banks (despite their publicity poses) are not that keen anymore.

  6. It doesn't add up... permalink
    November 18, 2022 10:55 pm

    Musk’s famous Big South Australian Battery has been making out like a bandit, earning almost A$13m this week for providing FCAS grid stabilisation services.

    Meanwhile wind curtailment has borne the brunt in South Australia. Not that other states don’t also have problems mainly arising from excess solar.

    At times curtailment has exceeded demand, so over 50% of generation was being thrown away. Far too much for the puny battery to absorb. A further problem is that curtailment is very spiky, reflecting daily rooftop solar peaks.

  7. Hugh Sharman permalink
    November 19, 2022 10:42 am

    Hilarious! 😂

  8. Tony Taylor permalink
    November 19, 2022 11:21 pm

    The extension of current network development is that all domestic customers (and perhaps commercial) operate their own power systems with solar & batteries and disconnect from the grid.

    • catweazle666 permalink
      November 20, 2022 3:28 pm

      That’s a LOT of batteries, I wonder where they going to come from?
      Plus, the fire brigades are going to be unhappy!

      • Tony Taylor permalink
        November 20, 2022 8:38 pm

        That won’t worry the zealots.

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