South Australia led the way on flexible exports for rooftop solar power systems – so what’s happening elsewhere in Australia? Here’s the state of play.
Distributed Network Service Providers (DNSPs) have export limits for solar inverters – often set at 5kW per phase. When the limit is reached, the inverter throttles output so it can’t export any higher, regardless of inverter capacity.
One of the reasons for these limits is to help reduce the risks associated with minimum grid demand events when too much solar energy is going into the grid and not enough is being consumed. Such situations can threaten network stability. Export limits also allow for more systems to be installed in a given area without expensive network upgrades.
The 5kW export limit wasn’t really an issue when the average solar system size was 6.6kW, which really wasn’t all that long ago. But systems today are bigger – 10kW and even larger is common.
There’s a better way – and that’s flexible exports done right.
South Australia A Flexible Exports Pioneer
South Australia was the first Australian state to offer flexible exports – and by and large, it appears SA Power Networks (SAPN) has done it right.
SAPN boffins developed software to forecast the network’s hosting capacity on a 5-minute basis, 24 hours in advance to help manage solar power exports of up to 10kW/phase per inverter. When the network can handle it and a system is capable, a full 10kW can be exported. When there’s too much congestion, a signal is sent to inverters to wind output back to as little as 1.5kW/phase until the event passes.
It’s not a case of the full 10kW export availability being very limited. SAPN modelling indicates the full 10kW is available around 98% of the time. SolarQuotes’ General Manager Trevor wasted no time in making the switch to flexible exports when it was available in his neck of the woods. You can also see details of a flexible exports curtailment event he experienced here.
The SA Government mandated flexible export capability for all new solar installations from 1 July 2023.
What About Solar Flexible Exports In Other States?
There’s more than one way to implement flexible exports – some more elegant than others. You’d think everyone else would have followed SAPN’s example given its success – but that hasn’t/may not always be the case; and that’s a problem.
Here’s the situation across the country; excluding limited trials in most cases. Much of the following information has been sourced from the Institute of Energy Economic and Financial Analysis (IEEFA).
Queensland
- Ergon and Energex have an opt-in only program using SEP2.01.
New South Wales
- In the Ausgrid area, it’s planned for FY26 using CSIP-AUS2.
- For Essential Energy, rollout is due before 2030.
- In the Endeavour region, flexible exports are planned from FY25 using CSIP-AUS and DERMS3.
Victoria
- Ausnet has an up to 5kW limit for constrained customers – and it involves proprietary technology.
- Jemena is looking to implement flexible exports from 2026.
- Powercor, Citipower and United are to all implement it over the 2026 – 2031 period.
Tasmania
- TasNetworks plans to undertake trials from this year out to 2029.
South Australia
- As of mid-November, 70% of the state (including all of the metropolitan area) can now access flexible exports. SAPN is using using CSIP-AUS.
Western Australia
- In the Western Power service area, implementation is expected by mid-2025.
- In Horizon Power’s region, it’s available with *no* export limit. It requires a secure gateway device; provided by Horizon free of charge.
Northern Territory/ACT
- I wasn’t able to determine what’s in the pipeline; although EVO Energy (ACT) says it will introduce flexible exports at some point – just not when.
IEEFA Weighs In On Flexible Exports
The IEEFA says all Australian energy customers could have their electricity costs reduced if flexible exports for rooftop solar power were enabled across the nation, as cheap solar energy pushes wholesale prices down.
But IEEFA guest contributor Dr Gabrielle Kuiper says given flexible exports are not being rolled out consistently or quickly, this is creating additional costs for inverter and gateway manufacturers, and unnecessarily increasing the cost to solar consumers.
“The implementation across six jurisdictions by 11 different distribution network service providers (DNSPs) is being planned or delivered using a variety of standards and devices,” Dr Kuiper says. “Unless there is a nationally consistent approach to communication and integration, meeting all requirements for all DNSPs will be a huge undertaking by industry.”
The IEEFA estimates delays to implementation cost households installing new solar systems and those with existing 8-15kW solar systems a combined A$35 million in 2023, through lost feed-in tariffs.
“This cost will accumulate to A$211 million over the next three years, and will grow further if the implementation of flexible exports is delayed beyond 2026,” the organisation says.
While FiTs aren’t as generous as they once were and maximising solar energy self-consumption is the name of the game, every little bit helps.
To minimise the cost of compliance to inverter manufacturers, Dr. Kuiper says basic common requirements could be put in place, and has urged the powers-that-be to lodge a rule change to look at options to not only fast-track flexible exports, but also to manage minimum system load. This includes ‘emergency backstop’ mechanisms; a different beast to flexible exports – but the latter can help avoid use of the former.
You can read more about how rapid implementation of flexible exports could maximise rooftop solar in a new analysis from the IEEFA.
Footnotes
- Smart Energy Profile 2.0 (SEP2) was created ZigBee Alliance with support from HomePlug Alliance as an energy management standard. ↩
- CSIP-AUS is a standard enabling smart inverters and energy management systems to work with dynamic/flexible connection options. ↩
- Distributed Energy Resource Management System (DERMS) developed by Mondo ↩
About Michael Bloch
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SEP2.0 I think is where the meter is Zigbee enabled. As far as I know, SA & Vic have Zigbee enabled meters, but I know NSW does not.
Why cant all the areas standardise the control & metering? This would allow consumers to view/use the immediate data from their own meter. This is by interfacing to a Home Management system (such as Home Assistant), or simply having a display where they can see real time data.
As more people increase the size of their PV, and even more people put PV on the roof, the consumer demand will reduce and more frequently curtailment will occur.
Why doesn’t a forward thinking SAPN have the consumer in-house hot water service turning on automatically, before any containment occurs, so that we maximise the use of surplus sunshine rather that increasing wasted opportunity?
Rather than charging at hot water rates the power so generated and used should not be charged at all (nor credit given) because there is no cost to SAPN
Hi Tim,
You could train meter readers to program the dumb time switches that we’ve installed for SA solar power systems since 2005ish
However AGL has been busy soaking up a few million dollars in ARENA funding to research whether moving controlled load hot water to the daytime would work. Results are in now so I imagine they’ll seek another round of grants to work out if the sky is blue and water is wet.
These things will come to pass but the incumbent industry has incredibly stup!d inertia and a propensity to maximise the profit from any change.
We should nationalise them.
https://arena.gov.au/knowledge-bank/plus-es-south-australia-demand-flexibility-trial-final-knowledge-sharing-report/
Wouldn’t nationalising them be great.
My understanding is that Ausgrid already allows 10kVA
Single Phase Maximum Inverter Capacity
NS194 Clause -5.3.1 – In accordance with Appendix C2 of AS/NZS4777.1:2024 Appendix, Ausgrid will allow up to 30kVA of total Inverter Capacity (including AC-coupled battery inverters) to be connected to a single phase supply point provided that the premise electrical installation is appropriately rated (e.g. switchboard rating, cabling) and the export to the grid is limited to no more than 10kVA (note this is above the 5kVA specified in AS/NZS4777.1:2024). A design must be provided showing how the export limiting will be configured.
2 approaches here,
1) do as you say and wait for some authority to make the change….try not to be surprised when this seems to take forever.
2) put in some really simple automation at your home and heat your hot water with your own PV output when ever its available and required. After all a forgone 6c is much better than paying 18c for the same capability at night.
If your inverter is old school, like mine, it wont care about household consumption, merely report what its creating. A dual Current transformer device that measures grid supply/export and PV output and can differentiate between export and import (direction of current flow) can be installed by your local sparky for Im guessing $100- $200 for the device and $200 fitment. It talks using WiFi or Zigbee back to a Home Assistant instance and then a $30 device/$100 fitment switch turns on the heater element when spare PV is available. Your tank thermostat allows the tank to consume PV until it reaches its setpoint, and opens effectively turning off the element.
Ive done it at my house and my hot water which is evacuated solar tubes anyway, consumes somewhere around 1-2kwhr of electricity at a time of day of my choosing. My Home Assistant has a solar estimation integration so I can get a pretty reasonable idea of how many kwhrs of solar remain in the day. If I’m being super efficient I don’t even turn the heater element on until later in the day so that most of the heating heavy lifting is already done by sunlight anyway. The heater element lifts it from say 55 deg C to 65 deg C….That’s all inside home assistant or some of its add ons at no cost to you software wise.
I use the same automation capability to turn my air-conditioners on and off during the day so that when its stinking hot outside its cool as inside and remains so until the sun goes down…. doesnt cost a Cent! Great way to prevent mass PV export going into the grid when it doesn’t need to….
Gone are the days where we had no control!!
Great story Andy.
Let us know where you think the best place to start is for a novice looking into Home Assistant.
Cheers
Anthony
Each of us brings life experience to the party. For some of us, that life experience is absolutely related/relevant and as such transition to making something really useful out of home assistant is simple and quick. For others their life experience may not have been directly related and as such its going to take them longer to achieve, and they may have to be satisfied initially with a simple project rather than working out a building management system for parliament house as their 1st project.
For me, I cruised youtube. If you feed in Home Assistant into its search then you’ll be blown away by the shear quantity of videos available to you.
If you know nothing about Home Assistant, or indeed anything about smart homes in general then I suggest you go to https://www.home-assistant.io/ and there you can read about what the software is and what it can do for you.
If I was to provide an one long sentance overview of what it is, Its an operating system for a computer that exists to manage smart things in your home.
The computer it loads on can be an old PC, cause smart home management is not a complex task or it can be a virtual PC loaded on your existing Windows 10, or 11 PC or a mac with virtualisation or containering software (Windows has that built in so no costs to turn it on and play with it via Microsofts Hyper-V software) you boot the virtual PC while your normal windows is running and then can from a browser on your normal PC connect and interact with the virtual PC Home Assistant instance.
Alternately instead of a full PC it can be a Rasberry Pi-5 or 4 or even 3 machine which can be had for $50-$150 and is not much bigger than a pack of cards. As is teh case in teh computer world there are pro’s and Con’s to each of these approaches. I started with a virtual PC on my normal home PC but relatively quickly moved to an older server/pc
+1 for Home Assistant.
I use HA to read the data from my Inverters (2 x SolarEdge, 2x Victron), & also use HA to control my ZJBeny OCPP EV charger. I use a IoTaWatt to measure my various loads. (There is an Australian agent selling IoTawatt).
My HA runs on an Intel NUC. (cheap s/h now: Celeron all that is required, 4G memory & 120G SSD or M2. Follow the instructions on HA site to load the s/w. Best on Linux…)
I would love to get real time data directly off my smart meter, but this seems not possible in NSW. Should be available in Vic/SA with Zigbee: Eagle 3.
because some of the cons to Hyper-V were not acceptable in my environment.
If anyone is interested, below is a link to the pdf print of the energy page on my Home Assistant for the 10th of December showing that while I produced nearly 22kwhr of PV power I only exported 7.3 of that to the grid. The remainder I consumed in the house mainly with Air-conditioning. A great Solar day for me is circa 40kwhr of production so presumably this was a mixed bag day with sun and clouds…
https://1drv.ms/b/c/ce605eccf1a3f587/EbrLv2-Trx9EhdL3auSXF1MBpcCnRowT4tLjjQu9uR-lSg?e=8X1hFa
Next a link to the energy management page that I created to better understand what is happening on a daily basis. Its for today. another mixed bag day
https://1drv.ms/b/c/ce605eccf1a3f587/EaocRZISJTlBq7-WYnnsEOoBw5Hr46NlE0iWB-FiXLHMcw?e=x1vxaw
I’ll be adding a battery shortly and swapping out my old PV system (6.5kw) for probably circa 18kw system. I’ll be swapping to Amber when I do and using Home Assistant once I understand my home needs for the above to maximise any sale of excess power back into the grid at rates that make it worthwhile…at least in the short term cause who knows where we will be in 1-2 years more…..
Thank you Andy,
That’s a really useful guide and I appreciate the time you’ve taken to explain it.
YouTube is a great starting point but sometimes finding what you need, (at the level you’re ready to understand) is like mining for gold… there’s so much work involved in moving the overburden.
So far, my experience with flexible export has been a bit different…
“SAPN modelling indicates the full 10kW is available around 98% of the time”
That depends very much on where you live, I think. The suburb that I live in is network constrained (it was one of the first suburbs where flexible-export-or-1.5kW-max was enforced).
We recently upgraded our 5kW system (with 5kW fixed limit) to 10 kW with flexible export.
Since about the start of September, we have been constrained to 1.5 kW export between 10:00 and about 16:00 on nearly all days. The unconstrained output from our system is usually around 8 – 9 kW over that time period, so about 20 – 30 kWh of lost export on those days depending on how much power we’re using. At a rough estimate the flexible export limit has cost us about $50 in lost export earnings (3c/kWh) this year.
That’s still a small fraction of what we’re saving from having the extra power especially in the early evening peak, but the “full 10 kW is available 98% of the time” is a long way off the mark for us; “60% of the time” is closer to the mark for us during Spring. My best guess is that the export limiting will cost us 20 – 30% of our export earnings over the year.
Hi Richard,
That’s a really interesting explainer.
Have you contacted SAPN about it?
I know of at least 1 other customer in your situation who’s complained enough that they’re doing a specific investigation & will likely re tap a transformer or perform other works to fix it.
I’ve found they’re usually pretty earnest about complying with the rules set for them by the national regulator in terms of supply voltage.
This is the time of year things can get interesting for solar oversupply.
I’m glad you’ve got a rational approach though. The $50 loss isn’t much to get upset about compared the the savings from solar in the first place.
Thanks Anthony, I might give that a go. I have found a very helpful contact at sapn called Mara who has been fantastic at answering my many technical questions about flexible exports.
Funnily enough, the export limiting doesn’t seem to be correlated with network voltage sensed by my inverter, even if I correct the reading for the voltage rise/drop caused by the net export/import from my property. Seems like there’s something more subtle going on.
Hi Richard,
Mara is very good indeed. Give her my regards 😉
I have a new battery system with an inverter restricted to 5kW (in WA it is the inverter that is restricted not the export limit). This is challenging when trying to avoid the import of grid power, especially when using air conditioning. So this prompted me to read the IEEFA article by Dr Gabrielle Kuiper to see what WA might be planning, and I was struck by how little cooperation/coordination there is between states. I guess that was the point of the article. But surely now that SA has a system up and running the other states should just fall into line? SA has done all of the hard work and it seems ludicrous to waste money and effort designing something different for the other states? Especially when they are mostly in one energy market.
Also I have noticed Facebook ads inviting SA customers to join up to flexible limits so they seem pretty confident.
But that didn’t answer my question about what WA are doing? The document says that Western Power will “finalise communications protocols, data, and technology requirements to predict and publish dynamic operating envelopes (DOE), in accordance with the [distribution network’s] co-ordination requirements” by mid 2025. Does anyone know if that is likely to lift inverter limits – especially for self consumption?
I had a 3-phase 15kW inverter system installed about a month ago and so far every day from roughly 9 am to 5 pm when it’s sunny, the system has been restricted to 1.5kW per phase. It’s so bad that I’m yet to see if my system can export its capacity to the grid.
SAPN have investigated and informed me that there’s congestion in my area (Prospect) and there are upgrades planned in the next few months. They haven’t been able to tell me to what extent these upgrades will fix the problem.
I estimate it’s costing me between $100-$150 per month. It’s also frustrating to think of all those people who can’t afford to run their air conditioners yet I have all this capacity on my roof that’s going unused.
SAPN state “On rare occasion, solar exports have caused pressure on the network. South Australia’s solution for this nationwide problem adjusts exports to balance demand in those rare cases of oversupply.” Surely this is false advertising.
Hi Matt,
Let us know how you go but we’ve found SAPN are pretty earnest about solving problems with exports.
They’re planning on doubling the throughput of energy on the network in the future and they want to do it with distributed solar, not massive infrastructure spend.