SA Power Networks Confirms 5kW Inverter Limit For South Australia

new rules

Installing solar in SA after 1 December 2017? Here’s what you need to know…

SA Power Networks Makes Radelaide Sadelaide

It’s December and the latest rules for connecting rooftop solar to the grid in South Australia are now available from SA Power Networks (SAPN).  I called them late last month to try and get a scoop on what they were planning, but no luck there — SAPN play their cards close to their chests.

So first thing on Friday morning I checked their website and found no change from November.  But that’s okay, I completely understand.  I know there are times people will say they’ll get things done by Friday but actually get them in first thing Monday morning.  Or possibly three weeks later.  That also happens.

But now they’ve had a whole week now to catch up and I see there have been some changes on their site.  There is movement at the station and I’m passing the word around.  The colt from old Regret has got away…

If you can’t be bothered to read this whole post then here’s what you need to know about installing solar in SA from 1 December 2017:

  • Only 5kW of inverters are allowed on a single phase supply
  • You can export limit a bigger inverter (up to 10kW)
  • SAPN doesn’t say you can’t oversize the inverter’s nameplate capacity by 33% as is normal
  • With single phase supply you can AC couple a battery as long as the total inverter capacity is less than 10kW and the system as a whole is export limited to 5kW
  • 3 phase homes can fill their boots with 30kW of inverters and 40kW of panels.

Inverter Limit for Single Phase Drops From 10kW to 5KW

It could be a lot worse, but regret is what I am feeling now.  While I did not have high hopes, it saddens me to see the days of South Australians being able to install 10 kilowatts of solar inverter capacity in a home with single phase power are now long gone.

You can install an inverter of up to 10 kilowatts if it is export limited to 5 kilowatts, but it’s not the same.  For one thing it costs extra and can result in some clean solar energy going to waste while coal power stations emit murder fumes with impunity.

If you have three phase power you can install up to 40 kilowatts of PV capacity, which is more solar panels than you can poke a roof at.  But I am still bummed out by the restrictions for single phase power, as that’s what most South Australians have.

It didn’t have to be this way.

While they are following the national standard (AS4777.1), Distributed Network Service Providers, such as SAPN, are allowed to make exceptions.  And I would like the exceptionally good connection standard we used to have for homes with single phase power restored.  It was cool to have a better standard than other states.

What happened to you SA Power Networks?  You used to be cool.  But at least you’re better than what people have to put up with in Western Australia, so there is that.

4777 Single Phase

The Australian/New Zealand 4777 standard’s inverter limit for single phase power.


Solar Inverter Size With Single Phase Power

Most homes in South Australia have single phase power and SAPN’s document, “Technical Standard — TS 129 Small Inverter Energy Systems (IES) — Capacity not exceeding 30kW” describes what these households can install.  I have excised out the relevant section and stuck it below for your edification1:

Single Phase

As solar panel capacity can be up to one third larger than inverter capacity, if you have single phase power you can:

1. Install up to 5 kilowatts of inverter with up to 6.66 kilowatts of solar panels.

2. Install more than 5 kilowatts of inverter capacity up to a maximum of 10 kilowatts with up to 13.33 kilowatts of solar panels — provided the system is export limited to 5 kilowatts.

This is only for new installations.  If you already have a single phase system that can export more than 5 kilowatts there’s no need to change it.

Single Phase Power And Export Limiting

A system that is export limited to 5 kilowatts is unable to send more than 5 kilowatts of surplus solar power into the grid to receive a feed-in tariff.  Export limiting has the disadvantages of costing extra to set up and can result in clean solar energy going to waste if the solar panels produce more than 5 kilowatts over the household’s power consumption.

The good news is, not much power is likely to be lost.  If a home has the following characteristics:

  • 10 kilowatts of solar panels
  • The solar inverter is export limited to 5 kilowatts
  • All the panels face north
  • No electricity at all is consumed during the day2

Then in Adelaide only about 14% of the solar electricity generated would be wasted.

If instead of facing north, the panels faced east and west, the amount of solar electricity wasted would only be around 11%.  If there was a moderate amount of electricity consumption during the sunniest parts of the day, either because people are at home or appliances have been put on timers, then the amount of electricity lost would be reduced, potentially to almost nothing.

Export limiting encourages batteries

A battery system could also be used to store solar electricity that would otherwise go to waste for use in the evening.  If solar electricity is regularly going to waste, this significantly improves the economics of battery storage.

Batteries And Single Phase Power

The good news for all you Tesla fans out there is it will be possible to install a Powerwall 2 even if you have single phase power.

I guess this is good news even if you hate Tesla but want to install their battery anyway.

Here’s what the new technical standards say:

If you have single phase power you can install an AC coupled battery with a battery inverter, provided the total of solar inverter and battery inverter capacity does not exceed 10 kilowatts and the system is not capable of exporting more than 5 kilowatts to the grid.

If you have single phase power with an existing solar system that can export more than 5 kilowatts, you can retain your current export capacity, but any battery you install must be configured for zero export and you will still be limited to a total combined inverter capacity maximum of 10 kilowatts.

A multimode solar inverter, also known as a hybrid inverter, can be used to DC couple batteries without the need for separate battery inverters, so installing batteries this way won’t affect your inverter capacity.  But only the AC version of the Powerwall 2 is available in Australia and it has a 5 kilowatt battery inverter.

Upgrading To 3 Phase Power Isn’t Cheap

If you don’t like the idea of being export limited or want to install more than 13.33 kilowatts of panels, upgrading from single phase to 3 phase power is an option.  In towns and cities the total cost is likely to be several thousand dollars or more and in rural areas it is likely to come to several thousand swear words worth of money, as it can be ridiculously expensive.

Update: 29th May 2019 – 3 Phase Power Allows Up To 30 Kilowatts Of Panel Capacity but must be export limited to 5kW per phase

If you have three phase power, as a small but slowly increasing portion of homes do, then you can install up to 30 kilowatts of panel capacity.  But most houses find it difficult to fit 10 kilowatts of panels on the roof, so if you want 30 kilowatts  of solar panels you’ll either need a damn big house or room to rack them up on the ground.

As of 29 May 2019 you can only export a maximum of 5kW per phase. So if your inverter or inverters are larger than this, you’ll need to export limit.

One final condition is the amount of inverter capacity on each phase must be within 5 kilowatts of each other.  This is not a problem if you are using a 3 phase inverter, but if you are placing separate inverters on each phase then they can’t differ by more than 5 kilowatts.

Inverter Size Of Up To 5 Kilowatts On Rural SWER Connections

If you live off the main grid in a rural area and have grid electricity, then you’ll be supplied by a Single Wire Earth Return (SWER) power line which is a low cost method of transmitting electricity long distances.  With these connections the technical standard says the maximum allowed inverter size is 5 kilowatts and that’s all it says.  Here, I’ll prove it:

Single Wire Earth Return

Note that while you can install up to 5 kilowatts, if SAPN determines the local grid may not handle it they can require you to install less.  But hopefully they won’t.

In Conclusion — I Am Sad

There may not be a single three phase home in South Australia that would come close to reaching its 30 kilowatt panel limit, even if the roof was completely slathered in solar panels, so this limit is not a big problem.  But it is a pity that people with single phase power can no longer install more than 5 kilowatts of inverter capacity without export limiting their systems.  I could argue that if three phase homes can have 10 kilowatts per phase without export limiting then single phase homes should as well, but I won’t in case SAPN takes it the other way and decides to reduce the amount 3 phase homes are allowed to have.

Update: 29 May 2019. ASPN have just reduced the export limit for 3 phase to 15kW

The extra cost of export limiting will result in less solar capacity being installed than if it wasn’t required.  This means more fossil fuels will be burned than would otherwise be the case and this makes me sad.  The reason why is because, after giving it some thought, I’ve decided that I’m in favor of living and against dying.

There are limits to how much distributed solar generation can easily be installed on the grid, but the amount is dependent on local grid conditions and so I don’t think we should have one standard apply across an entire state.  Instead we should allow people to install as much as is practically possible in their location and reward Distributed Network Service Providers such as SAPN, for increasing the amount of rooftop solar capacity that can be installed.

Because I am willing to put my money where my mouth is and because I will stop at nothing to protect the world that I leave to my children, if by this time next year SAPN has increased the inverter capacity homes with single phase power are allowed to install without export limiting, I will give everyone who works there an ice cream cone3.


  1. Edy really should stop ficating, but I don’t think he can help himself.
  2. Clearly it is the home of one of those odd families that believe refrigerators are the work of Satan.
  3. They won’t be $8 Haagen Darz ice cream cones, but they’ll still be nice.  There’s not a lot of ice cream in this world that tastes bad when it’s free.
About Ronald Brakels

Ronald was born more years ago than he can remember. He first became interested in environmental matters when he was four years old after the environment tried to kill him by smashing fist sized hailstones through the roof of his parents’ Toowoomba home. Swearing revenge, he began his lifelong quest to reduce the harm the environment could cause. By the time he was eight, he was already focused on using the power of the sun to stop fossil fuel emissions destabilizing the climate. But it took him about another ten years to focus on it in a way that wasn’t really stupid


  1. Steven Zilm says

    Ronald, can you please direct to the where the 33% inverter over sizing is in the SAPN rules? I know the CER rule (well, CEC guideline) but as I interpret the rules and guidelines if we install at BES (battery energy system) then the over sizing rule is not applicable.

  2. Steve Charles says

    Sad news indeed, and very short sighted. SAPN have taken an easy way out rather than dealing with line regulation issues. The limit of 5kW will encourage home owners to install batteries and more will consider going off grid altogether. This new ruling will also impact companies who want to set up virtual power stations. This is a regressive move by SAPN.

    • Clayton Elliott says

      Sadly in South Australia if you are on the grid then you must stay on the grid. Basically the regulation states that if you have a power line going past your house, you must have your house connected to it.

      I’m not sure if that means that you must by law have your house powered by it, just that there needs to be the connection to a meter which is on your house. If you then go and disconnect your house from the meter and connect it as a sealed unit, I’m not sure if there have been any legislation written to ensure that this doesn’t happen. Of course you’d also need to make sure that you have ample labeling and directions for turning off your power so then any electricians who do work on the house are capable of turning off the power before they commence work.

  3. It’s pretty obvious they have reduced the maximum export as there are just too many people installing Solar now and the local area can’t handle it for whatever reason (can be many) but they still keep issuing the SEG approvals, how many applications ever get knocked back?. Once you hit 250V at the inverter it starts to down RAMP the maximum power, this is for SA, don’t know about states.

    I have 6.48 kW panels and 5 kW inverter and even on a cloudless days (close to the Summer solstice now) it often stays between 3-4 kW being generated. I can observe with voltage monitoring and as soon as it hits 250 Volts the down ramping starts. The Inverter power graph at the end of the day looks like Bart Simpson’s hair-cut because of the up/down RAMPING.

    On occasions my Inverter switches off because the voltage gets too high. PowerSA recently installed a new cable back to the pole and a new main Fuse box because one early evening the lights were flickering in all rooms (including fridge). The new cable fixed the excessive voltage drop from house to pole which stopped most inverter faults but there is still an issue on the grid itself. If it’s a hot day and locals have their Air-conditioning switched on I can get up to 5 kW.

    When the inverter switches off the grid voltage is exposed but is still over the allowed limit (253 Volts) that PowerSA have to observe. This is all logged and can be compared with the Inverter graph power.

    This ramping requirement is a little known fact and I have only became aware of it recently. PowerSA has me booked in for a Polygraph logger for house and pole but that was about 5 weeks ago now. You have to keep on at them to get things done.

    • Stewart,

      The ramping on high grid voltage is part of the Australian standard for solar inverters AS4777.2.

      Generally it shouldn’t happen very often if the voltage rise from your inverter to the grid is less than 1% (i.e. your wires to the grid are thick enough).

      You may find this useful:

      • Thanks for the link Finn, so the ramping affect is called “Volt-watt response mode”.

        On the old cable back to the pole (mid 70s) I did some unloaded and loaded testing by measuring AC volts then switch on all elements of my electric stove, measure volts again and it was about 6 volts less. An electric kettle would make it drop about 3-4 volts so from that I can determine the voltage drop over the cable. If I just double that and say 4800 Watts (my inverter is 5kW) then I was looking at 6-8 volt drop and that is basically the same as what happens with the inverter. Combine that with what the grid was also doing and it was shutting down up to 20 times or more per day.

        Now with the new much thicker twin cable it has halved that value so consequently far few inverter shut down errors. Even so the Inverter 10 minute voltage level has been increased to the PowerSA maximum permitted of 258 Volts but still trips out occasionally.

        The ramping aspect of it happens every day.

        This is my live logging of volts on the EmonCMS site. Click on “W” to see past week voltages. The big dips are around midnight when off-peak HWS are switched on around the area:

        Looking back over time it rarely ever gets down to the nominal 230 volts and is always high.

        • I have the same issue. I get the Bart Simpson hair cut every mild sunny day. Over 30 degrees and the wives of the neighbourhood use AC and I can actually hit 5kw and reach clipping! No shutdowns, it doesn’t go above 254 but I suspect a couple more solar installations would do the trick.

          • And I bet there are many people with Solar that have the same issue but they probably have no idea what is occurring unless they monitor it. They are probably happy with their power bills but fail to realise the full potential of their systems.

            My last build was about $18 credit but in reality it should have been much higher credit with more export.

            Of course if every house in the street had solar then exporting could no longer be counted on if they supply all their own power. In the end storage is going to be needed somewhere in some form or if possible PowerSA have storage dotted around the local area so that it can be used at night. Could we call that Power to the node? (PTTN)

    • Steve Charles says

      Following some communications with SAPN about the new 5kW solar inverter export limit, I can only conclude that there are no technical reasons behind the move other than complying with AS/NZS4777 published by the EL-042 Committee. Most of the changes in AS/NZS4777.2 are sensible improvements to safety of solar installations, but no reasons are given for the 5kW inverter export limit. Instead of imposing such a limit, the capacity of the low voltage network could be strengthened through better voltage regulation, but whilst such solutions are being trialed in SA and other states, there is no general implementation to solve the problem. So, the 5kW limit is simply a quick fix to buy time. However, this is wishful thinking given the announcement yesterday of the world’s largest virtual power station in SA which will certainly add to reverse power flows. The new limit also discriminates against those households who already have solar PV and wish to upgrade it. TS129 says they can’t go over the 5kW limit. I have argued with SAPN that the new limit will have unintended consequences and will encourage more households to go off grid. For example, if you already have 5kW installed, you can’t also install a Tesla Powerwall with a 5kW inverter, so the only solution will be go go hybrid and have the inverter feed the house. As solar and battery prices continue to fall, It will soon be cheaper for some to go off grid altogether and be done with the network.

  4. And, whilst this is not in SA, but, in the hick state of WA, the issue of maximum inverter capacity and overloading, becomes even more complicated, when, in WA, the nominal inverter capacity is subjected to a multiplicative factor of 1.1, so, as in the case of this household, instead of 5kW of nominal inverter capacity being allowed, only 4.5kW of nominal inverter capacity is allowed, being assessed by the powers that be, as 4.5 = 5 (in this state, where it was determined that the installation of domestic rooftop photovoltaic systems, brought with them, invisible meter-reader eating monsters, that stopped the electricity company from reading the electricity meter, and, where it was determined that the use of domestic rooftop photovoltaic systems, caused an immediate and prolonged increase in grid electricity consumption by houses with such systems, which use grid electricity to power the sun).

    But, that is what happens, when the electricity companies, which have a direct financial interest in rejecting and obstruction the installation and use of domestic rooftop photovoltaic systems, and, which have grossly overpaid rich fat cat executives and grossly overpaid rich fat cat CEO’s, control the approval (and rejection and obstruction) process for installation and usage of domestic rooftop photovoltaic systems.

  5. Would it be possible to publish a comparison of what will be allowed for each state/territory?

    Also, in the article, is

    If you have single phase power you can install an AC coupled battery with a battery inverter, provided the total of solar inverter and battery inverter capacity does not exceed 10 kilowatts and the system is not capable of exporting more than 5 kilowatts to the grid.

    If you have single phase power with an existing solar system that can export more than 5 kilowatts, you can retain your current export capacity, but any battery you install must be configured for zero export and you will still be limited to a total combined inverter capacity maximum of 10 kilowatts.

    A multimode solar inverter, also known as a hybrid inverter, can be used to DC couple batteries without the need for separate battery inverters, so installing batteries this way won’t affect your inverter capacity. But only the AC version of the Powerwall 2 is available in Australia and it has a 5 kilowatt battery inverter.

    1. About what price, is the cost of a multi-string (with multiple orientations of panel arrays) MPPT inverter that allows up to 10kW of generating capacity and limits export to the grid, to 5kW, and, that has capacity for connection toi a battery storage system, separating the battery storage system from the grid? References exist, to such inverters, but, pricing is too difficult to obtain (if they exist, rather than being figments of imagination, like Powerwall 2 batteries being available for domestic usage).

    2. Can inverters be operated in series, so that a 5kW (export limited) inverter from a photovoltaic system, can feed into a series (in serial) of Powerwall 2 batteries, so that what is connected to the grid, is a single (the last in the serial connection) 5kW inverter, thus, complying with the restrictions, but, maximising the use of available energy?

  6. We are only allowed 5kwh inverter on 3 phase here in Perth 🙁

  7. John Herbst says

    “Good news… only 14% of your household solar would be wasted”

    Good news everyone…

    SAPN has no constraints.
    SAPN could correct any constraints with cost-reflective critical-peak pricing (during actual constraints, the price could drop to zero or even negative, which is cost-reflective!)
    Proper use of technology is not driven by constraining it, but rather by rewarding it.

    Example: Customers lacking space for solar may still buy a battery in order to buy local solar. There is 14% less solar being sold by the example household and bought by shady customers or apartment-dwellers, or shady businesses, etc, etc,. Community models are made more complicated for no good reason.

  8. Do you know if there is any reason for the limit on inverter size? To the casual observer it would seem that it should have no effect on SAPN how much inverter capacity you have – the only thing that should matter to them is how much gets exported.

    Is there some technical justification for the 10kw inverter limit? Or are they just unnecessarily limiting options for consumers?

    In my case it would make it difficult to ever install a battery in the future as I have an existing 8.2kw Fronius Primo inverter, so I would have to either DC-couple the battery or find a battery with 1.8kw or less inverter capacity and I don’t think either of those would give me many possibilities. I don’t see it being worthwhile for me to get a battery any time soon, so perhaps it doesn’t matter, but it would still be nice to have the option.

    • Steve Charles says

      My personal view is that the limit is arbitrary and I can’t think of any technical reason to limit inverter size. The real issue as I see it is the problem SAPN have regulating line voltage. Each inverter, irrespective of its size contributes a voltage rise to the network, and this can become an issue on semi cloudy days that will vary the output of thousands of PV installations. Limiting inverter size will not impact on line regulation issues at all, so why do it?

      • Steven Zilm says

        Steven Charles… well the technical reason is network stability, primarily to control load masking. What happens when there are numerous large solar (or multiple small) self consumers of energy and cloud(s) comes over….? There is a huge demand spike causing frequency shift and an unstable grid…. voltage rise is mainly an issue at the consumer connection point…. as most of the networks big transformers have AVR (auto voltage regulators). But hey, shoot me down if my analysis is incorrect, I believe the blogs editor is an electrical engineer, ….I’m only a dumb sparky!

        • Well what sort of “Auto voltage controllers”? Some mechanical thing that raise/lowers the tapping in the transformer and scares the heck out of a ring tail possum only to be found dead on the ground next day? Yes, there should be better line regulation and it probably requires some form of electronics control, are they using such technology? I hope so. If the Home Inverters have fancy control why can’t the SAPN have the same sort of technology?

          As for the feed-in from the fossil-fuel generators that should sort itself? The less load on the generators the less hard they have to work and consequently less fuel needed. Try spinning a small electric motor (used as generator) with wires shorted out to see the braking effect.

        • Steve Charles says

          Thanks Stewart. As I understand it, when you suddenly load a large generator, the frequency drops due to the spin of the rotor slowing. So, the frequency instability comes from the power station itself, so this is a problem for the power generators who are not providing sufficient power on demand for the expected load.
          PV inverters do not contribute to frequency instability as they are synchronous inverters, that is, they synchronise their output to the mains frequency. If the mains fails, they disconnect.
          PV inverters do contribute to a voltage rise in the grid, and this should be managed by voltage regulators. There are now voltage regulators that are designed specifically to manage the voltage variations caused by solar PV.
          Modern solar inverters can also output reactive power (this is where the current lags or leads the voltage) which can also help stabilise the grid voltage.
          As I said, I can think of no reason why network companies should limit PV output to 5kW. It won’t change a thing except undermine the solar industry. Does anyone else have a better explanation?

          • Steve sounds logical to me what you stated, I’ll just add that voltage rise is unavoidable (no conductor is 0 Ohms resistance) but can be kept at low levels and the amount of rise can be known in advance by the cable used and if we get really technical the temperature of that cable, resistance in connections adds to it so can’t rely on calculations alone but the calculations will be the best case scenario. Simpler to do a load/no load test to determine the voltage rise with Inverter off or at night time. Unfortunately that also takes into account the impedance of the grid in so we don’t know where the issue lies.

            This is where SAPN can monitor the voltage on the pole and at the fuse box (using a Polygraph unit) to determine the voltage drop to the pole. If the voltage drop is more than the calculated voltage drop then they can suspect the cause may be poor terminations, contact or inter-wiring, etc.

            Apart from the above the reason for the voltage rise is due to the grid impedance and if that is high then you get a proportional amount of voltage rise. You have to expect some especially where SAPN run flimsy thin cables between the houses. Also we need others using power to keep it down. In a perfect world pushing back into the grid only causes the voltage to rise if there is not enough loading to CLAMP the voltage. If one were to push 240 volts into a short circuit over 5″ long one inch diameter cables it would try to draw a massive amount of current. There would be some small voltage drop over those cables but the fuse will blow before you can even get a chance to measure it.

            Hopefully if enough consumers nearby are using power it will help to clamp the voltage to reasonable levels. This is why on hot days when the A/C units are switched on the down ramping in the Inverter is greatly reduced (for me anyway).

            The impedance issue on the SAPN side is something they must deal with but I doubt they will spend the money to do so and the consumers would end up paying for a neglected power distribution system.

            So far today I’ve had 4 x 301 grid errors, typical week-end issues with voltage rise issues. This has revealed that when the inverter is off the line voltage is over 253 Volts and that’s with some normal house-hold appliances running placing a small load on it. If they were off it would show a bit higher than what I’m logging. So as I see it SAPN are in BREACH of the standards.

            Now it could be someone in the area has their inverter configured with certain values to avoid ramping and other over voltage issues but that is a something that SAPN need to investigate if they are the not the root cause themselves.

  9. In the above article, is

    If you can’t be bothered to read this whole post then here’s what you need to know about installing solar in SA from 1 December 2017:

    Only 5kW of inverters are allowed on a single phase supply
    You can export limit a bigger inverter (up to 10kW)
    SAPN doesn’t say you can’t oversize the inverter’s nameplate capacity by 33% as is normal
    With single phase supply you can AC couple a battery as long as the total inverter capacity is less than 10kW and the system as a whole is export limited to 5kW

    and at
    (datestamped three days earlier, so, may need updating) is

    Using rooftop solar to get your electricity bills down to zero is pretty straight forward. Put plenty of solar panels on your roof and make enough money in feed-in tariffs so you don’t have to pay a cent on your electricity bills, or better yet, get paid for the electricity you provide. Unfortunately, there there is a pretty big problem in most people’s way. The majority of Australian homes have single phase power which limits them to installing a maximum of 6.66 kilowatts of solar panels.

    Now, regarding (and, only applicable to) single phase grid electricity supply and applicable inverters;

    1. Regarding the export limited inverters, where up to 10kW of inverter capacity is allowed, as long as the inverter is limited to exporting 5kW,
    1) what is equivalently applicable in WA, and
    2) is the export limiting, limiting only what gets exported to the grid, or, limiting what is output from the inverter?

    I note that, in my meter box, the fuse (for electricity to and from the grid) for the single phase connection, shows as a 60/80A fuse (Type 11 415V … Series 7… 8S 1361 (“…” used to indicate line break on the fuse container label) ) which, for 250V, gives (using P=VI) 60×250=15kW, or, 60×415=24.9kW maximum capacity of the fuse, and, therefore, assumedly, of the connection to the grid electricity supply.

    If the export limiting, applies to only what gets exported to the grid, and thence, not to the output of the inverter, then, assumedly, a 10kW inverter, export limited to 5kW, could be supplying up to 10kW to the household consumption, and/or battery charging, where a multimode inverter is used, and, any surplus electricity generated, up to 5kW, exported to the grid, which may thence require, for example, something like a 10kW inverter, feeding into the household (and any battery storage therein) electricity supply, and, between the household switchboard and the grid connection, a throttle, to limit export to the grid, to 5kW.

    So, I think this is worthy of clarification.

    2. With an inverter of up to 10kW output capacity, which is export limited to 5kW, what is the maximum nominal capacity (as opposed to effective capacity, once considerations like efficiency due to orientation) of the attached photovoltaic panels, that input into the inverter? Is it the 1.33 times the export limited maximum, or, the 1.33 times the inverter capacity, or, another value?

    And, once again, regarding the last previous paragraph, what is applicable to WA?

    • Ronald Brakels says

      Hello Brett

      1. (1) Households in WA appear to be limited to installing 5 kilowatts of inverter capacity, regardless of whether they have single or three phase power. (2) Export limiting only affects what is exported to the grid. Unfortunately, export limiting is not normally permitted in Western Australia, as far as I am aware.

      2. In Australia, an on-grid system that receives STCs can have a PV capacity that is up to one-third larger than the inverter capacity. Off grid the PV capacity can be more than one-third larger, provided it is within the manufacturers recommendations. But my understanding is STCs will only be received for panel capacity up to one-third larger than the inverter capacity. This should be what applies in WA.

    • Steve Charles says

      Thanks Stewart and Bret for your comments. I still can’t see any benefit to SAPN or grid stabilisation by limiting PV inverter output to 5kW. Given that previously 10kW was allowed, this is a pointless and retrograde step that only serves to make it more difficult for households to put enough solar on their roof to limit the impact of ever increasing costs of power. It will do absolutely nothing to help stabilise the grid. If it does, will someone from SAPN explain how.
      I can see that, over time, as PV and battery prices come down further, it will encourage more households to go off grid altogether and disregard the limit.

      • Steve, I think it’s being done because the more PV systems there are in an an area the less that then can be exported by each customer. SAPN are the authority that approve/disapprove Inverters to be installed. They want to keep approving systems because that means an instant $300+ for them to install a new meter it which takes ~1/2 an hour and the meter does not become your property. You just pay $300+ for the installation. I don’t even know any Engineering consultants that command $600 per hour.

        Also their policy has been that if an inverter is interfering with other power consumers then they have the right to have your unit decommissioned if the problem is not remedied. So if it was causing voltage to be over 253 volts for your neighbour they could order for it to be disconnected. (See information in the SEG approval they send you).

        Having 10 kW limited to 5 kW is not all bad though and it can make up for dull days. That’s the advantage to over sizing. A 5 kW PV array might only push out 2.5 kW but a 10 kW system will reach it’s maximum inverter limit of 5kW under the same conditions.

        • Steve Charles says

          Thanks Stewart. I am going to ask Mr Stobbe directly what are the technical reasons for limiting PV inverters to 5kW. He, and his staff have always been very responsive to my queries in the past. I know they are doing a challenging job, but there must be a sensible reason behind the decision. I can’t see it though.

        • Steven Zilm says

          Well you may have been right about metering in the past but as of 1 December SAPN are no longer in the metering business… it’s now contestable and the responsibility of your retailer….

          • That is not entirely correct.

            According to:

            As long as your SA Power Networks meter remains, we will continue to look after it and undertake meter reads.

            My new digital meter was installed and owned by SAPN back in April 2017 when I had the solar installed. I know that as mentioned above I paid over $300 to SAPN for it to be installed.

            Pretty sure the model I have (EM1200) does not have wireless communications. Currently meter reader was just reading straight of the LCD display. It does have an optical port so whether they start to use that on my next meter read I will see. Last read was a day or two before 1st Dec.

            Having each retailer read their customer’s meter might be good as it might stop the Switching games they play but according to what I quoted above it will still be SAPN that read mine.

            Besides there are many retailers out there now. What if only one or two customers in the same street? Drive up the road to read the next meter? Really? They would need to use a 3rd party service like they do now to do everyone house by house.

    • Apologies if this info is out of date, I’m not sure about the exact situation in SA but I’m guessing it’s very similar to WA. From what I remember in my studies regarding the sizing of your PV inverter it has something to do with the continuous max current carrying capacity per phase.
      There can also be issues I believe with over voltage safety cutoffs in the inverter which become more prevalent at higher kW rated models running off a single phase and connected to the grid. This also intereacts with the distance to the nearest transformer and what max voltage that grid transformer has been set to, what time of day it is, industrial or residential etc etc.
      It’s not necessarily a straight forward issue, so I believe it is probably a one size fits all model that fits some more than others. If you want more capacity to produce, upgrade to 3ph power and you can pump out 5kW per phase. Or wait until the interconnected grid is upgraded to support distributed power generation, good luck. BTW I thought the supply voltage was legal so long as it stayed within the 220-264 range?

      • From SAPN’s own documentation it states:

        Under the Australian Standard, the voltage for household customers must be maintained between 216 volts and 253 volts. Until 2000, the Australian Autandard was 240 volts but this was amended to align South Australia with current national and international standards.

      • Steve Charles says

        Andy, I think you may be right on this one. What the network companies should be doing is upgrading the infrastructure to minimise volt drop and to handle bi-directional current flows. Instead, they choose to undermine the solar industry and to create a disincentive for households to install solar PV. This, at a time when we need renewables more than ever.

        • Anecdotally, every employee I’ve ever met from SAPN – and I’ve probably met about 12 now – has a deep mistrust and/or dislike of solar. It is quite stunning. They see it as a pain in the ass. This leads me to believe that there is a deep anti-solar culture in SAPN.

    • Steve Charles says

      A response to Stewart above.
      It is my understanding that the impedance of the power network is very low and this is caused by the large number of households and businesses connected to it. The impedance of solar inverters is very high and does not load the network, but in order to export power, it must output a voltage higher than that of the network. Hence, the voltage rise caused by all solar inverters.
      Solar inverters do not output a sine wave, but give out current pulses that are synchronised to the grid. Hence the term synchronous inverter. The low network impedance forces the voltage waveform to be followed.

  10. In the second-last paragraph of my most recent post above,
    “considerations like efficiency due to orientation”
    should instead be
    “considerations like efficiency due to orientation are taken into account”.

  11. David Graham says

    The limit is only for NEW installations, right? If we already have more than 5 kW, we are not affected???

  12. MK Tree Hugger says

    This is all a way to scam by SA Power Networks to maximise the retailers bottom line at the expense of consumers who want to reduce their bills because of the price gouging and share price activities of the power generator companies to maximise their income. Where is the state and federal government in all this? Why aren’t the politicians saying enough is enough? because they are making money out of this as well via lobby groups. Grow some BALLS Australia and tell your local politicians you have had enough.

    • Steve Charles says

      Hi. SAPN are not power generators and simply provide the network infrastructure that connects homes to the grid. I can appreciate that they have a difficult job to do balancing the grid, but the recent decision to limit solar PV installations to 5kW is beyond my comprehension. I have asked for an explanation.

  13. I have a 5kW inverter with 5kW of panels (in S.A.)
    Early Nov I decided to install a separate solar system due to panel compatibility issues. SEG approval was granted and the new 3.8 kW system will be installed in January. Separate inverter will be 3 kWhr.

    Will I be limited to the 5kW export? As the approval was prior to 1st Dec, will this not apply? I am in Adelaide and am hoping that timing has been lucky for me.


  14. Aaron Murphy says

    So, Ronald, are you saying, as you can now only export 5kW, they still won’t let you have say 2 Tesla Powerwalls (if you require that sort of nightime power) because why exactly??
    What if I’m using 10kW at my single phase home because I have lots of appliances and air conditioning because it’s hot, but I don’t use it all the time, that energy goes to waste due to the 5kW limit? Well done Australia.

    • Ronald Brakels says

      Hello Aaron

      If you have single phase power you won’t be able to install two Powerwall 2s and have rooftop solar. Since each Powerwall 2 has a 5 kilowatt battery inverter having two of them would bring you up to the maximum allowed total of 10 kilowatts.

      If you have 10 kilowatts of solar panels that are export limited to 5 kilowatts then at times solar electricity will be wasted. Hopefully this won’t be much. It might only come to 5% of the total generated, but it will still result in clean solar electricity going to waste that could have been used to displace fossil fuel generation.

  15. Peter Cleary says

    When State governments sold there electricity generation capacity to private companies, they must have had to guarantee earnings to those companies in order to obtain the best possible price. No company would pay billions of dollars for a product such as electricity generation if the returns were to be reduced because people generate their own power via solar panels. Surely, there are contractual obligations to the private enterprises now generating power, which are responsible for regulations making it more difficult to harvest as much domestic power as possible from solar panels.

  16. Aaron Murphy says

    Exactly! Thats what I’m so concerned about. We have clean solar energy going to waste when it could be going to the grid (best option) or if that fails, to a battery. Instead, dirty fossil fuels need to cover that ~5% and even though 5% isn’t much it adds up.

    Do you know the reasoning behind limiting battery inverters as well as solar inverters to 10kW total? As far as I understand batteries help the grid rather than make it unstable as shown by the Tesla big battery.

    • Ronald Brakels says

      There are limits to how much distributed solar can easily be added to the grid, but I don’t think we are anywhere close to pushing hard enough against those limits given that people are dying from both toxic pollution from coal generation and global warming. I think that, as a country, we can do far more to encourage the installation of rooftop solar.

  17. Yes, this is the real “foreign political influence” that should concern us all. When the Rules conflict with the secret handshakes, a deal must be broken.

  18. yeah yeah yeah….OR you could go stand-alone, and f…labbergast the lot of ’em.
    This (not particularly-clever) soothsayer predicted l-o-o-o-o-n-g ago that the bastards ALWAYS shift the goalposts and WILL ALWAYS continue to do so. Far enough down the track people will be paying for the privilege of being allowed to export power to THEIR grid.
    WAKE UP people……and also you denizens of SA.

  19. Steve Charles says

    I have written to the SAPN Network Standards and Performance Manager requesting a technical explanation for the new 5kW solar limit and will pass on the response when it comes. As I see it, there is absolutely no benefit to this policy as voltage rises (and associated network voltage regulation issues) are caused by the number of invertes connected to the network, not the size of the inverter. Limiting the size of the inverter achieves absolutely nothing other than undermine the solar industry.

  20. Steve Charles says

    On a related matter, for those with solar PV on the roof there is always the question as to who offers the best electricity tariff. For example, do you go for the cheapest supplier per kWh or the one offering the highest feed in tariff. There will be a crossover point. Has anyone done the math?

  21. As a three phase home owner in SA I do feel blessed.
    Can you please confirm 2 things for me that are not clear in the SAPN approval docs.

    1) Your peak capacity of inverter is what is counted not the peak capacity of panels – in the 30 kW you mention? If so, then why does SAPN ask for and approve the peak panel / production capacity, it’s arbitrary isn’t it

    2) The difference of 5 kW between phases, this includes or not the battery inverter peak capacity? So for example, I have 3 x 4.6kW inverters plus 5 kW battery inverter.

    Even though I have the approvals to read over again and again, it still doesn’t seem written for normal people. 🙂

    • Ronald Brakels says

      Hello Mark

      As far as I am aware the 30 kilowatt limit for 3 phase power applies only to the inverter so it should be possible to install up to 40 kilowatts of panels, assuming you have the space for them.

      Keeping inverter capacity on the phases within 5 kilowatts of each other would also apply to battery inverter capacity, as I interpret the rules. You set up should be fine as none of your phases would have more than 5 kilowatts of inverter capacity difference between them.

  22. Steve Charles says

    Good. I will take a look. I have also been looking at the various feed in tariffs offered and the two with the highest FIT in SA (20 cents) impose a 5kW limit. So if you have more than 5kW on the roof, then tough. They are certainly making it difficult for homeowners to get the best out of their PV systems. Thankfully, the company I am currently with pay 12 cents/kWh on everything you feed in.

    • I created a Spread sheet so that I could enter plans for various market and standing offers so I could easily see which one suited me best. For this I entered my quarterly usage for all 4 1/4s. I just averaged it out for a year but in reality it needs to calculate each 1/4 bill separately as the amount of energy imported and exported varies over those periods. The data I entered was for a non-solar house.

      Trying to determine the amount of Peak power usage for day night needs some guess work unless the Bill provides that and you have a smart meter that uses wireless communications. I have a smart meter but it’s not that smart and meter reader has to come out each month and just reads the Peak, Off-peak, and Exported data of the LCD display. Having a good Energy monitor is a good solution so that you can monitor it yourself.

      I’m an exporter way more than an importer so the plans that favoured better export returns was my preference. Just going by the feed-in tariff is not enough, all the rates need to be taken into account such as Peak, Off-peak, Daily supply charges, Discounts and the smoke screens making it difficult to really determine how the discounts actually work as they can differ from plan to plan. Then their is also the first 10 kW or so of usage rate and other rates on top of that differs. My calculator ignores the last on as I don’t normally use that much especially now that I have solar so just use the first rate.

      On the 5kW limit I saw that too in one of the plans when I looking at switching, I think it may have been “Click energy”, it was not clear what they were referring to so I asked on their Chat service if it was inverter size or PV size. Was told Inverter size. I would could confirm that in writing if switching just to make sure. I think I saved that chat somewhere but their Off-peak rate was quite high so I went with AGL on their “Savers Energy Plan” which gives me 16.3c/kW feed-in. I had to until July 2017 for all the new plans to be announced as they changed dramatically which suited me as I save even more now. Last bill was $0 pay and $18 credit, expect next one to be even better.

      Whatever plan you select they often expire after 12 months and reverts to a standing offer. Problem was they had not been informing customers it was about to change. I think they now have to inform the customer by law it’s going to change but whether you will have enough time to switch providers will be another issue.

      They use all sorts of tricks to make switching as difficult as possible by delay it an extra 1/4. You often spend a lot of time on the phone to an OS call centre then have it escalated back to Australia. Repeat that a few times as nothing is happening and many customers just give in and I think they know that full well. This is something the ACCC should be cracking right down on. That happened to me but eventually they were forced to do a retro-switch after I got the Energy Onbudsman involved. That was Energy Australia that refused to allow me to switch away because they claimed I had not informed then I wanted to leave. Switching providers in SA means you just contact the new supplier and it happens automatically and you don’t need to do anything further.

      • Ronald Brakels says

        I don’t know what their current policy is, but Click has accepted people with more than 5 kilowatts of panels in the past. Of course, I guess that could have been a mistake.

  23. Steve Charles says

    Yes, Click Energy and Amaysim both offer the best feed in tariffs (20c) but will allow only 5kW to be exported. Diamond energy allow up to 10kW but offer only 12c FIT. Of course, the higher the feed in tariff the higher the power prices, so it is very difficult to work out what is best for you. The online power comparison sites don’t take these factors into account.

    • Surely you mean 5kW inverter and not 5kW exported?

      • Steve Charles says

        Yes, it is a maximum of 5kW for the inverter that is allowed.
        Origin Energy offer an 18 cent FIT on all power generated, but I have just read that this is only for the first year. After that, it reverts to 11 cents.
        I also looked at smart meters as I thought it would be good to access import and export data directly, but my power provider does not offer a portal to access the data so there is no point in proceeding.

        • If you are supplied though SAPN you can now create an account to see your data. I just created an account to try it out. It shows all my usage for my last bill from Sept-Nov but all under November because meter only read every 1/4.

          If it was a smart meter (it’s just a brand new digital meter!) it would probably be read daily. So as it is it’s of not much use for me as it just shows last bill usage but I can see that on my bill. I guess it might be useful to check against what your retailer claims you are using.

          Sorry but posting a link seems to be impossible here now, no error reported just takes me bak to top of page. So maybe this will work. Add 3 * w characters at the beginning then replace all “_” occurrences with forward slashes, also replace all “$” occurrences with a “.”:


          • Steve Charles says

            Yes, I have set up an SAPM My Meter account but it is not much use for real time monitoring. For that, I use CarbonTrack which gives me real time data on power generated and power used. On hot days like these it is invaluable as I can monitor the impact of my of my ac against power generated and ensure my ac is always free, or very low cost. No bill shock here.

  24. Test only. I can’t reply to a Steve Zilm post, tried many times but just keeps taking me back to top of page and no waiting for approval mesg. Is there some character in the post the blog does not like? Sometimes it comes back with – You have already said that.

    • I was expecting an explanation and not really for the bug report post to be approved. Anyway I tried replying to Steve Zilm post again but removed the WWW link to SAPN document this time and it posted, just waiting for approval now.
      Still waiting for another post on 19th to be moderated and approved which I had posted earlier than the other one. is the site having issues?

  25. There was an update from sapn to allow total capacity of pv inverter and battery inverter to 20kwh with up to 10kwh each.

  26. Steve Charles says

    Regarding the 5kW export limit recently introduced in SA, this is explained in the Technical Standard 129 available on the SAPN website. All installers must comply.
    It would have been better for SAPN to invest more in the bi-directional capacity of the low voltage grid and improved voltage regulation than putting the brakes on solar installations in this way.
    I have been communicating with SAPN about this for some time. The energy minister doesn’t seem to be bothered about it even though it will impact VPS plans.
    I have pointed out that it will encourage more people to consider going off grid altogether rather than be constrained by TS129.

  27. I have just found out that I am ineligible for the Tesla VPP deal because I already have 2 x 5 KWH invertors . I have 9,4 KWh of solar panels. As Tesla has a 5KWh invertor this brings the total to 15KWh – not that I am putting out more power.
    What an absurd situation – obviously they want us to choke on coal dust.

  28. Mats Andesson says

    Another interesting issue with the export limit in SA is that if you have a two phase house (as we have) it counts as a one phase house and the export limit is 5 kW! All according to our solar cell installer.

  29. Your bright yellow highlighted text summarising the state of the nation seems to be incorrect due to being a couple of years out of date.

    You state “If you have single phase power you can install an AC coupled battery with a battery inverter, provided the total of solar inverter and battery inverter capacity does not exceed 10 kilowatts and the system is not capable of exporting more than 5 kilowatts to the grid.”

    However on the SAPN website the summary is this:

    “In summary, this will mean the total inverter capacity for a single phase installation can be up to 20kW (10kW PV and 10kW battery).”

    • No way to edit posts? Anyway I posted above and it actually didn’t seem right to me what is stated on the SAPN website about being able to put up to 20 kW of inverters on a single phase so I downloaded the TS-129 Technical Standard document on this subject and sure enough it contradicts the website information stating only 10 kw is allowed.

      So I called SAPN to find out which is correct, their website or their document? After a long time on hold while they conferred they said the 10 kW figure is correct, and apologised for the wrong info being on the website……

  30. What happens if I already have a single phase 8kw inverter and I want to put in a 5kw Tesla battery?

    I would need to upgrade to 3 phase but say I’m using 2kw from the grid on the phase without the inverter does that mean that the inverter can export 7kw on the phase it’s connected to for a net export of 5kw?

    • Ronald Brakels says

      Hi Brett

      No need to upgrade to 3 phase power as the Tesla Powerwall 2 won’t count towards the inverter limit as it is zero export limited. (Except when operating as part of a VPP it won’t send power into the grid.)

  31. Sorry, just realised that this article was for SA but I’m in Vic (although I believe they are similar limits now). Ausnet have already knocked back an application for battery and inverter on single phase due to inverter capacity being above 10kw, even though it is export limited to 5kw

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