SA Power Networks Limits Three-Phase Exports To 15kW

Solar power and three-phase in South Australia

If you’re a South Australian who needs three-phase output from your solar power kit, I hope you’ve already made your application to SA Power Networks for approval, because from the end of May, new rules limit three-phase export in that state to 5kW per phase.

The change was foreshadowed: in April, SA Power Networks confirmed the export limits for three-phase solar inverters would be cut, and with the publication of its technical standard on May 30, that throttling has come into effect.

The change reversed a decision we discussed in December 2017. At that time, SAPN limited single-phase export to 5kW, but allowed 10kW per phase export on three-phase systems – as we put it at the time, “3 phase homes can fill their boots with 30kW of inverters and 40kW of panels”.

Those halcyon days are over for three-phase users – under the new technical rules, they’re subject a 5kW per phase limit, for a total of 15kW, in effect putting them in the same boat as single-phase owners. And, of course, that also halves the maximum customers can reap back for what they feed into the network – which would have been a savage hit if it applied retrospectively.

That, fortunately, is not the case. SA Power Networks emphasised that it only applies to applications for connection received after May 31.

“The new three phase limit applies to all applications after 31 May 2019 — noting there is a period of grace for applications received up to 31 May,”

a spokesman for the company told us in an e-mail:

“For applications received up to 31 May 2019,  the installation and connection must be completed by 30 August 2019 or a new SEG application will have to be made and the new three-phase export limits will apply.

“What we have done is apply the existing 5kW single phase export requirement to a three-phase installation. We are now aligned with the national guidelines developed after broad industry consultation, including with the Clean Energy Council.”

Why the limit?

SA Networks has two justifications for its decision – national standards, and the capacity of its own network.

In 2017, we noted the utility is following the AS4777.1 standard, but it does have wriggle-room to make exceptions – that’s one reason the 30kW export limit lasted so long.

In changing tack last month, SA Power Networks says the limitations of its own network, most particularly the “last mile” where the wires are thinnest (and, we suppose, oldest), have forced the change. Quoting from its April statement:

“The rapid increase in the installed capacity of inverter energy systems (IES) across South Australia into an electrical network originally designed for one way energy flow has presented a number of challenges to the safety and reliability of the distribution network.

“It is important to remember, every powerline has a finite capacity to accommodate the connection of solar and batteries, before technical issues arise. Remediation of these issues in some areas is uneconomic and is not in the best long-term interests of all cost sharing electricity customers.”

As previously, SA Power Networks also calls on the authority of national standards to justify its decision:

“This is consistent with Energy Networks Australia (the national industry association representing Australian electricity networks and gas distribution businesses.) releasing the National Distributed Energy Resources Grid Connection Guidelines on 7 March 2019. In preparing these guidelines, Energy Networks Australia (ENA) consulted broadly with industry including the Australian Energy Market Operator, the Australian Energy Market Commission, state and federal governments and the Clean Energy Council as well as each of the fourteen utilities across Australia.”

You’ll notice that there was very little consumer representation in those deliberations. The closest the consumer is to the consultation is the Clean Energy Council, which represents Australia’s solar energy industry. While we all have a stake in our customers getting the best deal, nobody is speaking directly for consumers, and that’s outdated in a world where customers are also electricity generators, and deserve a greater voice in discussing trade-offs that affect them.

About Richard Chirgwin

Richard Chirgwin is a journalist with more than 30 years' experience covering a wide range of technology topics, including electronics, telecommunications, computing and science.


  1. Hi,

    Wow, imagine that ithere is no solar in SA. Lots more people, building lots more homes. More power usage all round. What would they do about the power lines then? Have brown/black outs for customers? No, they might possibly, maybe, probably would think: “I think we’re gunna need a bigger line.”


  2. Can you please confirm, I already have approval and installation for 3 x inverters on my 3 phase home. These inverters however are 4.6 kw capacity each.
    If in the future I wish to replace them with higher capacity I will need to redo my application and therefore will be rejected? Or is it that I am already approved for 10kw / phase and do not need to make a subsequent application.

    • Hi Mark,
      I do more SEG applications than anyone in SA, (cause we do the most installs)
      If you upgrade your inverter to higher than 4.6kw each, then this will be classed as a new upgrade and then the load limiting of 15kw will apply. for 3 phase, or 5kw for single phase,
      If you are on one of the old feed in tariffs of over 30 cents per KW you will lose this feed in rate as well and be reverted to the new tariff of around 12 cents.

      Your 10kw per phase will stay un-load limited as long as you do not increase the KW max of the current inverters or panels.

      • Thank you Daryl,
        I am on retailer tariff only.

        I can’t see any reason to upgrade until panels at least double in output capacity, maybe not even in my life time.

        However, it is funny is it not, I am load limited to 10 kW per phase and in order to keep this higher limit I must keep my original equipment. This equipment can’t produce the said 10kW output anyway, this effectively means I am now bound by the same limit as a new install. Why approve for a 10kW per phase install if the equipment being installed can’t even do half of that ? Bizarre

        • It Should Happen in your life time, The improvements lately are huge.
          They have just recently discovered by adding fluoride to solar cells it will double their output, BUT, it will also half the life of your panels as well, BUT
          They will keep developing panels to a higher level, so the changes are coming fast.

  3. Clarifying for a friend : if they already have a large system (eg. 28kW) already installed and running for the past 12+ months, feeding in essentially non-export-limited (10kW per phase)… do they have to call their installer to come back and put into the system export-limiting?

  4. Brian Knight says

    Regarding the SA Power Networks limit on exports to the grid of 5kW per phase, what exactly does the limit refer to? Is it per day, per year or something else? This is quite critical when trying to assess the economics of adding a battery to an existing solar system.

    • Hi Brian,
      Its per hour,
      5kw per hour , per phase

    • Ronald Brakels says

      Hi Brian

      If you have single phase power you are only permitted to install a 5 kilowatt solar or a larger one that is export limited to 5 kilowatts. This means you can either have a 5 kilowatt inverter with up to 6.66 kilowatts of solar panels, which is the practical limit, or you can get a larger inverter that is export limited so it never sends more than 5 kilowatts of power into the grid at any time.

      If you have three phase power you can have a maximum of 15 kilowatts of inverter capacity. This could be one 15 phase inverter or three 5 kilowatt inverters — one on each phase.

      A battery system will be export limited so it has a battery inverter it won’t affect your inverter capacity.

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