The Grid Wants To Control Your Solar Inverter — But Only For Good, Not Evil

Solar inverter control

Thanks to a deficit of trust in government, people are rightly worried when they hear that ‘the government wants to be able to switch off their solar systems’.

On the 30th of April the AEMO or — as it’s known by the long-winded — Australian Energy Market Operator, published a significant report called Renewable Integration Study 1.  A few people read the summary and then wrote articles on how the grid wants to take control of people’s solar inverters; switching them on and off as they desire.

Some of the stories made it sound downright sinister.  As a result, I’ve had one person tell me they’ve changed their mind about getting solar installed because “the government” will take control of their system and stop them from saving money – and I’m sure there are more people like him out there.

AEMO Report Appendix A: The Grid Only Wants To Control Your Home A Little Bit

But having read through all 54 pages of Appendix A — the part that focuses on rooftop solar,  I can assure you that our grid overlords only want to take control of our solar inverters for good and not evil.  Here are five reasons why there’s no need to panic:

  • Solar inverters will only be remotely shut down during grid emergencies to preserve its stability.
  • The overall loss of solar energy generation from remote shutdowns will be trivial.
  • It may be a cheaper way to provide grid stability than other options, saving money overall.
  • It may never happen, as it’s only under consideration at the moment.
  • If it does happen, we are still years away from requiring new residential solar inverters to have remote shutdown capability.

Even if you regard my above reassurances as being mere blandishments and still fear the thought of your inverter falling under the thrall of your local Distributed Network Service Provider1, you have no cause for concern yet, as no solar inverter currently on the market can be remotely shut down by them.  (Some inverter manufacturers can control them remotely, but no one seems to care about that.)

In this article I will quickly cover:

  • How distributed solar power is rapidly expanding and why this is a problem for the grid.
  • Helpful changes for new solar inverters that don’t involve remote control.
  • Why a mandatory remote shutdown function is likely to benefit solar owners.

You’ll also discover that our evil grid overlords aren’t intending to prevent all rooftop solar from exporting electricity to the grid.  Well, some of them are, but hopefully, they are outnumbered, and the less evil grid overlords will prevail.

The Grid Struggles To Keep Up With Solar

New approaches are required if we are to avoid throttling how much solar energy can be exported to the grid on new installations or even cutting exports all the way to zero. Up to now, local grids have been running a Red Queen race where they have to run as fast as they can just to stay where they are, but some are slipping behind.

“A slow sort of country!” said the Queen. “Now, here, you see, it takes all the running you can do, to keep in the same place. If you want to get somewhere else, you must run at least twice as fast as that!”
— Lewis Carol, Through the Looking Glass

Rooftop solar power is expanding fast, for good reasons:

  • It’s an excellent investment for nearly every home with an unshaded roof.
  • Its price continues to drop — solar panels have never been cheaper than now.2
  • It reduces fossil fuel use, cutting pollution and damage to the environment.3

This graph from AEMO’s Appendix 1 shows actual rooftop solar capacity up to late 2019 and two projections out to 2030 for the National Electricity Market or NEM, which consists of the ACT and all states except Western Australia.  Because rooftop solar is “Distributed PV” the graph calls it DPV for short:

Historical and projected installed distributed solar PV capacity in the NEM

My well-educated guess is the higher forecast is more likely to be correct due to:

  • The falling cost of solar.
  • The uptake of electric vehicles.
  • Home and business solar batteries falling in price and becoming cost-effective.

But this only applies if the grid manages to stay one step ahead of — or perhaps only one step behind — the rate of installation and allows households to continue to export their surplus solar electricity to the grid.  If the grid can’t keep pace and starts preventing new systems from exporting, it will significantly reduce the number and size of systems installed.

Operating the grid smoothly becomes more difficult as the amount of distributed solar increases.4  This table shows the maximum percentage of total electric power consumption met by rooftop solar panels in the eastern states in 2019 and two projections for what it may reach by 2025:

Historical and projected maximum instantaneous distributed solar PV penetration

The Australian PV Institute‘s information indicates that in South Australia rooftop solar met 68% of total electric power consumption this year on Monday the 9th of March, meeting the central prediction out to 2025 already5:

Percentage of electricity demand met by solar photovoltaics

Unseen & Uncontrolled

The report describes rooftop solar as both “invisible” and “uncontrolled”.  Depending on the type of person you are, you may regard this as either:

  • Very bad, or…
  • Totally awesome.

The reality is between those extremes.

Invisible means grid operators can’t directly monitor the output of rooftop solar power systems.  Since they can’t see it, they say it’s invisible.  By that standard, I could claim to have an invisible car just by parking it behind a shrubbery.

When they say rooftop solar is uncontrolled it means, just as they can’t directly see what the systems are doing, they can’t directly control them either.6

Instead of using the word “uncontrolled” the AEMO report also uses a technical term with the same meaning.  That term is “passive”.  If you are discombobulated by the fact the words “uncontrolled” and “passive” have the same meaning, then you’ll understand why these reports can be difficult to get through.7

Despite being “uncontrolled”, solar inverters are very polite and will shut down to protect the grid if they detect a problem.  Unfortunately, if there is a lot of rooftop solar, this creates a situation where a relatively minor grid disturbance can shut down a large number of solar systems at once.

It has been estimated a grid disturbance in Adelaide at the wrong time could simultaneously knock out 400 megawatts of rooftop solar power: up to one-third of the city’s electricity consumption. It would be equivalent to a major power station suddenly going offline.  It has the potential to turn what could have been a minor problem into widespread blackouts.

While grid disturbances have previously resulted in considerable amounts of rooftop solar suddenly shutting down, these events haven’t caused severe issues so far.  But it’s only a matter of time before a significant event happens at a time of high solar energy generation and causes widespread blackouts.  This would be inconvenient for two reasons:

  1. Being blacked out is annoying for households and expensive for businesses.
  2. Fossil fools would go on about it for weeks, despite most of Australia’s generation related blackouts being the result of unreliable, old coal power stations breaking down.

Triggering events could be the result of lightning strikes, transmission failures, a fault in a conventional power station, a problem in a substation, or an actor mistaking a real fuse box for a movie prop.

New “Ride-Through” Capabilities For Solar Inverters

AEMO does not want tens of thousands of rooftop solar systems suddenly shutting down and causing widespread blackouts. So they want new solar inverters to have “short-duration voltage disturbance ride-through” capabilities. And they want them in SA and WA fast, as they are most at risk.  Here are two action recommendations from the report:

solar inverter ride-through capabilities

These changes to inverters will not allow their control by outside forces.  The solar inverter will achieve the ride-through capabilities itself using its firmware.

But if local grids require the upgrading of existing solar inverters, then I’m sure some people will get their knickers into a twist.  The good news here is it’s only likely to involve older inverters installed before October 2016. That’s when the most recent version of the inverter standard (AS4777.2) kicked in.

Provided there is an incentive to upgrade old inverters or replace old systems with new ones, that’s fine with me.  It’s when sticks are used instead of carrots and bully boys with lightning bolts on their lapels go around telling pensioners to shut down their old solar systems, or they’ll be kicked off the grid — that’s when I get upset.

The Power Of Money

The AEMO report says most of the changes required to keep the grid stable are possible with market incentives.  If electricity costs less when solar energy output is high, then people will use more, and those with batteries will store more during those periods, helping grid stability.  The power of market forces to solve these kinds of problems is often overlooked, especially by politicians.

But in an emergency market forces can’t always act quickly enough to stabilise the grid and so it is necessary to have other methods in place.8

Remote Control For Solar Inverters

One method to help keep the grid under control is to allow its operators to remotely shut down solar inverters if required.  This is called “load shedding” and is something all conventional power stations must do when required to protect grid stability.  But before you declare the grid can only have control over your solar inverter when they pry it from your cold, stiff fingers — I want to make it clear that:

  • This would only be in emergencies.
  • The total loss in annual solar energy generation would be trivial.
  • While relatively easy to do for commercial solar this is still years away for residential PV.
  • It may not be considered necessary and so never be required for households.

At the moment they are only investigating the idea, and there are no solid plans to proceed.  All they have at the moment is four bullet points:

Distributed solar generation shedding

While they appear to be strongly leaning in the direction of being able to shut down solar inverters remotely, it still may not happen. And if it does, the requirement that new inverters must have the ability to be remotely shut down is still likely to be years away.  No inverter on the market now has remote shutdown capability9. So if you are paranoid about losing control over your solar power system, you have nothing to worry about for a long time.  You can install solar panels while being confident that if the grid shuts your solar inverter down it will be because of overvoltage or another grid problem that got out of hand and not because they did it directly.

Some Concerns

We want to keep the grid stable and distributed solar power to continue to export surplus electricity into the grid for others to use.  Improving the ability of solar inverters to “ride-through” grid disruptions and making them able to be remotely shut down during grid emergencies are likely to be low-cost methods that help do this.

However, some issues need to be addressed.  Remote shutdown must only be used in emergencies to keep the grid stable and not when someone’s crony needs to make a few extra bucks from their coal power station.  While this isn’t an issue at the moment, vigilance is necessary to make sure this kind of thing doesn’t become a problem.

One issue we definitely need to deal with is security.  People will not tolerate security flaws allowing unauthorised interference with their solar inverters.  Despite the fact they are okay with authorised persons in other countries — inverter manufacturers — having the ability to screw around with much of our solar generating capacity should they decide to do so.

At SolarQuotes we have heard tales of cheap Australian battery inverters being controlled from the manufacturer’s HQ in Shanghai without the owner’s consent – albeit to try and troubleshoot a technical issue.

Hopefully remote control of solar or batteries for less honourable reasons will not happen, as inverter manufacturers make their money from exporting expertise. Backstabbing their customers wouldn’t just be shooting themselves in the foot, they’d also be shooting themselves in the wallet.  But I still think we should have an emergency plan just in case.  We should also keep this in mind when working out how any remote shutdown signalling will work in practice.

Footnotes

  1. Distributed Network Service Providers or DNSPs take electricity from high voltage power lines and distribute it to local homes and businesses.  They can be statewide as in SA, or there can be a bunch of them like in Victoria and NSW.
  2. Never cheaper at the factory gate.  But our dollar is weak at the moment, so we do not see all the benefit from this.
  3. I know I felt much less guilty about my greenhouse gas emissions after installing solar.  However, as I’ve been experimenting with German cuisine lately, I may need to add another 8 kilowatts to offset my increased personal emissions.
  4. Operating the grid also becomes more difficult as aging coal power stations become more unreliable and regularly breakdown with great irregularity. Still, I won’t go into that now.
  5. While electricity use has been lower than usual lately, the figure was close to 68% on Sunday the 11th of January, before the coronavirus response reduced electricity consumption
  6.  I suppose they could ring people up and ask them to turn them off or maybe throw a sheet over them to turn them down, but that would get old real fast.  And making snide comments to “throw shade on them” doesn’t work.  Solar panels have way too much self-confidence for that.
  7. Actually, this report is clearly written compared to some I’ve had to wade through, so kudos there.
  8. While market forces alone aren’t likely enough to keep the grid stable, they can still act very quickly if software allows for an automatic response.  And even when a human is in the loop, we can still act pretty fast.  If I got an SMS saying, “$50 if you cut your electricity consumption to under 200 watts in the next 30 seconds,” I would move like Usain Bolt.  (Well, maybe like Usain Bolt with another Usain Bolt strapped around his middle.)
  9. As of October 9 2016, all grid-connect inverters installed in Australia must conform to AS4777.2:2014 and allow disconnection from the grid if they receive a local signal on one of their hard-wired terminals – the dreaded Demand Response Enabling Device DRED0 signal. But for remote disconnection, the grid needs to get to your smart meter terminal from its master control room. Rolling that out to millions of homes will be far from trivial
About Ronald Brakels

Many years ago now, Ronald Brakels was born in Toowoomba. He first rose to international prominence when his township took up a collection to send him to Japan, which was the furthest they could manage with the money they raised. He became passionately interested in environmental matters upon his return to Australia when the local Mayor met him at the airport and explained it was far too dangerous for him to return to Toowoomba on account of climate change and mutant attack goats. Ronald then moved to a property in the Adelaide Hills where he now lives with his horse, Tonto 23.

Comments

  1. “I’ve had one person tell me they’ve changed their mind about getting solar installed because “the government” will take control of their system and stop them from saving money”

    CRIKEY! Why would we mistrust The Grid to do the right thing?*

    Lessor
    * Still fighting Synergy to (re)pay six different renting families the 47.135c they’re owed by The Grid. Latest in this ongoing saga? They accepted this new tenant’s FiT Rebate fees… then paid him just 7.135c.

    • John Mitchell says

      I’m in NSW so out of interest I decided to take a look at Synergy’s website. Not exactly what I’d describe as renewable friendly. REBS seems like a scheme designed to stop people installing solar. Good luck.

  2. So they make it a law so that the Inverter must be connected to the Internet and be accessible by any government body (by opening up a port) and/or demanding the Solar manufacturer to update the Firmware so that the government can request them to shutdown any inverter but using automatic methods and not a phone call to say please disable Inverter XYZ.

    This won’t require a new Inverter to make it possible.

  3. So now the true purpose of the NBN is clear, as you’re required to leave the NBN on 24/7 – $50bn+ invested to steal our roof top PV generation.

    All becomes clear…

  4. koen weijand says

    how would the control communication implemented ?
    most likely by using PLC,power line communication. that is already there in the smart meter, so maybe it’s not a big hardware rollout.

  5. I had an experience where my inverter wasn’t running at full capacity because the line voltage in my area was too high.

    I am not sure what the intent of taking control over inverters is, but all the provider needs to do is to float the line voltage above the threshold that I suspect Ronald is talking about in the AS4777.2 revision, and inverters will automatically stop producing power, forcing us to use Grid power from Fossil fuel and Pre-2016 solar Inverters.

    • I agree Tim, I also had my inverter switched off due to line voltage being too high during the summer months. What is the point in installing solar panels?
      Makes no sense to own solar panels when aus grid disallows your panels to export into the grid.

      • Chris, I used to have the same problem. It was caused by voltage rise being excessive and the Inverter has to shut off by law. That’s done inside the Inverter and not externally controlled.

        The run back to the street may need upgrading. That fixed my issues and PowerSA finally had to fix it (at their cost) when my lights started to flicker because of an overheated fuse box. They replaced the cable and the outside fuse box.

        The Installer should have done a Voltage rise check for your installation and by law they must produce the paper work to prove it if you ask them for it.

        • Of course it won’t! Despite protestations of honesty and fidelity (and Ron is wrong!), they can – and often do – disconnect inverters from the gid. eg when a line goes down, or requires work.

          • Hey Sylvia, nothing better to do except trolling?

          • Sylvia, “they” do not disconnect inverters from the grid when the line goes down. That is a safety measure programmed into the inverter. If the inverter detects no voltage in the grid then it shuts itself down to prevent people working on the line from being electrocuted by your solar system.

      • It is even more sinister.
        I am not so hung up on exporting to the grid, that is a nice to have, I try to focus on self consumption first.
        In this particular case, My system had the potential to produce 5kW but was being throttled to produce only 1.5.
        In the meantime I was Running my 2.7kW A/C Plus the rest of my house using grid power.

        When we peek behind the “Why” Curtain, we find that there is an oversupply of solar back to the grid. These pockets follow a socioeconomic grouping of suburbs with owner occupiers

        Finn’s frequent anti-batteries (for now) rants may not take into account this problem. If your system is prevented from achieving its full production potential, payback calculations change significantly, batteries now become the ideal solution for both the Grid and the consumer.

        The socially just answer would be for the grid to subsidize batteries in these problem, high supply, areas.

        An even better answer is to dig up my local sporting ground and install an underground system of mass energy storage devices. If space isn’t a problem, Tank Batteries can provide an effective solution.
        The 8 AFL posts can double as air vents in the winter, special, replaced with hollow cricket stumps in the summer.

        • John Mitchell says

          Finn’s not anti-battery?! He owns Tesla Powerwall 2. I think the name you’re looking for is Ronald and even he isn’t “anti-battery”. He just rightly points out that commercially available battery systems do not pay for themselves within their warranty. And he objects (also rightly) to companies advertising them that way.

  6. The very fact that this is being discussed at all I find scary as we all know gubmint’s have a penchant for control of the population look what’s happening now and aren’t some of them loving it.
    As we are hopefully going back to normal soon but in a much more subdued way for a long time I suspect, someone may have realized that we won’t have the money to upgrade the grid as required without raising the electricity cost and we can’t do that if we want to be re-elected.
    I think someone has foreseen a financial need to smack down the peasants if required to avoid any extra outlay even though this does not seem possible in the short term even if most of us will not be able to buy an electric car to recharge while we shop or work to soak up all that sometimes unwanted daytime solar.

  7. Beau Truax says

    Government has no right to do that, they need to keep their damn hands off of peoples belongings. This idea is stupid as f***. JUST ONE MORE WAY TO CONTROL AND WATCH EVERYTHING…SCREW THEM

  8. jim gleeson says

    Scratch them … & that shuddering fear of the deep-state comes rumbling to the surface …

  9. I understand the problem, but it is hard to comprehend why the regulator even contemplates turning off inverters, like letting treated water (a precious resource) run down the street, wasteful.

    Surely we can come up with a smart solution – why doesn’t the regulator mandate that large battery storage plants (like South Australia’s Tesla battery) be built by the operators, and they can then draw on that ‘excess’/invisible/whatever you want to call it) power when they need it, instead of having to pay these same perators an exorbitant ‘start-up’ rate when there is a genuine need for more power i.e. don’t waste solar power that someone paid good money to have produced, only to later pay a ridiculous penalty when power is needed in a hurry,

  10. I cracked up as I read some of this article.
    Standing back one has to remember we have a coal owned government working for,,,wait for it….the coal industry. That should be as clear as mud after 6 years of the buggers trying to fund new coal fired generators whilst shutting down one renewable agency after another.
    If this government is given control of our systems they WILL shut them down.

    The problem we have is that our government has refused to make changes to the grid to integrate renewable energy. Why? Because it wants the industry to fail and coal to regain its monopoly.
    Anybody who has watched South Australia’s stability in recent years would understand that this is due to renewable energy AND a battery storage system. No need to shut this system down. So where’s duplicate systems in all the major cities? That is the question our complicit media outlets should be asking their elected government but stay well away from.

    Lets be serious guys, this is not a ‘bad solar’ policy coming up, its a take control and then sabotage policy. When we get a government which government for the people then the negligence we’ve seen for so long will fade away. Until then fasten your set belts whilst the ride continues.
    If my solar is compromised I will be forced into buying an expensive battery and going off grid. So will others. No amount of legislation is going to be able to block that one. Lets hope sanity prevails.

    • You need to take your Solar tinted sunglasses off.
      Anyone who has studied SA supply for the past few years would realise that it would fail daily if it was not for the 100% gas generation back up they have and the continuous support they gain from Victorias coal generators !

      • Ronald Brakels says

        People used to say renewables were useless because they hardly provided any power at all, but these days they say they are useless because they don’t provide all of it. That’s quite a change.

      • Richard, what portfolio do you hold?

  11. Sylvia Jones says

    Hey Ron! Would you give some faceless bureaucrat ‘control’ over your wife/ love-life on the same basis and ‘arguments’??…. Or even what brand of dogfood you feed your dog?
    ….

    • Ronald Brakels says

      If my dog food decisions were causing 400 megawatts of electricity generation to crash, I would accept some regulation on it. But if my love life was doing the same, I’d take it as a sign I was doing something right.

  12. Hi Mick. Query: If you don’t trust the ‘authorities’ to tell the truth/deal honestly re. the suggested ‘dealings’, why would you trust them as re. the cost of batteries? The fact is that many more people are successfully running their houses (and some, to my knowledge, even their cars) on battery systems that are more than economically feasible than though not the latest gee-whiz technology touted by the in-crowd.. Mind you, they use their systems with an older, much more practical philosophical mindset than the more ‘recent’ darlings.
    KISS!
    ps. Do you remember the old question about jumping off a cliff just because your friends did?

  13. Ken Seeber says

    I have an electric car that we only charge from home during the day when the sun is shining. This is because if we purchase electricity from Synergy (WA) we pay 25 cents/kWhr, but if we sell it, we get only 7 cents.
    So, my question is: Where is the switch? Is it only to stop me exporting to the grid or will it disconnect the solar/inverter system (upstream of my house system)_ totally and then I am charging my car at the full purchase rates (26 cents), meaning they I am not able to use my solar system for myself (= a total waste of resources and investment)?

    • Ken, you only export excess energy that you don’t self consume. If it did not go out to the grid it would be wasted. It sounds like you need some device that will only charge your car when there is enough sun shine which is often 2 hours either side of midday.

      You could use a timer for that but what you really need is a device to sense the amount of power you are generating at any one time and regulate the charger.

      A Wifi device that gets the current power being produced by the Inverter could be used for control it but unless you are an engineer to design your own you would have to see what is available for your inverter.

    • Ronald Brakels says

      Hi Ken

      You can switch your inverter off, just follow the shutdown instructions, but that will stop all solar production. When you solar system is turned on your home will use the solar energy generated first, and only the excess will be sent into the grid. If you want to charge your EV solely off solar energy — which makes a lot of sense in WA — you will want a charger that will only sends solar electricity that would otherwise be exported to your car. There are a number on the market with the Zappi being one example:

      https://www.solarquotes.com.au/blog/zappi-ev-charger-review/

  14. Charles Brown says

    The following ABC news article suggests that replacement inverters would be able to be externally controlled:
    https://www.abc.net.au/news/2020-05-20/concerns-over-plan-to-switch-off-household-solar-panels/12267162?fbclid=IwAR3f3yVo0LEbFmdKVf6j4wldQGXE3jTQ5OG58a7oVdSI-29dwhnw3EEoiuM
    “AEMO said existing panel owners would not be asked to retrofit their systems but they would be caught up in the changes if their inverter needed replacement. The lifespan of an inverter is about 10 years.”

    I expect that those of us using enphase microinverters would not be affected since enphase microinverters don’t need replacing.

    Does anyone have any more information about that assumption?

    • “…since enphase microinverters don’t need replacing.”
      Charles – I know nothing about the reliability of Enphase microinverters but there is a fundamental rule of the universe which says that EVERYTHING wears out eventually. I doubt that Enphase can avoid that.

    • Ronald Brakels says

      First remote shutdown capability would have to become a standard for inverters on installation. This could take years. After that, the feature should only be used in grid emergencies. It’s the sort of thing that should happen less than once a year and only for short periods of time. So while it’s something we may need to keep an eye on, it’s not a cause for excessive concern.

  15. can you access stored energy in a battery during potential shutdown

    • Ronald Brakels says

      If the battery system is capable of providing backup power then it can island your home and supply power. It’s possible for battery systems to do this so quickly it’s not even noticed.

      But note the home will still be able to use grid power if the solar inverter is remote deactivated, so there’s no need to use battery back up.

  16. Erik Christiansen says

    Ronald,

    Remote shutdown of domestic inverters is a priori an unambiguously hostile act with undeniably hostile intent. If the intent really were grid protection, then the planned facility would instead be EXPORT INHIBITION, for the love of Mike! Technological home invasion to unnecessarily rob the homeowner of self-consumption can only have one motive – propping up fossil power generation beyond its use-by date.

    There is no defensible pretext for the proposed overreach, and no good reason to demand internet access to your inverter. A network tone would amply suffice for modeswitching a compatible inverter to suspend export.

    If the delusional overreach is not a late April Fool’s joke, then it is the strongest possible reason for going off-grid. My brother is in the process of doing so, and I already am off-grid. So let the devil take the hindmost.

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