Many Australian homes are not allowed to export more than 5 kW to the grid. If they want a big solar system with an inverter larger than 5 kW, they must ‘export limit’ the inverter. Here’s what that means.
Rooftop solar works by turning sunlight into electric power. The power is first used to meet household consumption, with any surplus exported to the grid for other people to use.
If at any moment in time you are generating more solar electricity than you need, the excess is exported to the grid. (Image from Finn’s Tesla App)
Exporting surplus solar power is good because it reduces fossil fuel generation and pays you a feed-in tariff that reduces electricity bills.
It’s becoming common for solar inverters to be export limited, so the maximum amount of power they send into the grid is less than they’re capable of providing. This is done for three main reasons:
- The Good: It can allow a household to install a larger solar power system than would normally be allowed. A larger solar system increases the amount of solar energy available for the home to use and — despite the export limiting — increases the number of kilowatt-hours of energy exported to the grid. This increases the environmental benefit and savings on electricity bills.
- The Bad: When a Distributed Network Service Provider — the people in charge of local poles, wires, and sub-stations — gives approval for rooftop solar panels to be installed, they can restrict the amount of power allowed for export to less than is usually allowed. In this situation exporting limiting can enable the household to install a solar system large enough to meet most of their electricity use during the day, while still enabling them to export a considerable amount to the grid.
- The Ugly: Homes can be prohibited from exporting any power to the grid at all. In this case, export limiting an inverter to zero can allow the installation of a solar system that helps meet daytime electricity consumption, but it won’t receive any feed-in tariff at all.
In this article, I’ll give a broad outline of how export limiting works and why it can be a good idea.
I know in the movie the Bad was worse than the Ugly, but that’s not the way I’m doing it.
How Export Limiting Works
When an inverter is export limited, it has to know how much solar energy is being sent into the grid so it can immediately reduce output if it’s about to go over the limit.
The ideal way to measure the power flow in and out of your house would be to ask your existing electricity meter. Unfortunately, the meter companies and inverter manufacturers can’t get their shit together, and the utility meters refuse to talk to the inverters. So the solar inverter has to have its own energy meter installed in your switchboard – one that talks to the inverter to tell it when power sent into the grid reaches the export limit.
This extra meter adds to the cost of a solar system. Here’s the ‘Fronius Smart Meter’ that you need if you want to export limit a Fronius inverter – it will add about $500 to the cost of the system:
An example of how export limiting works — You have an inverter that’s exported limited to 5 kilowatts. It is delivering 8 kilowatts of solar power. You’re using a total of four kilowatts to cook your lunch, so your home is exporting 4 kilowatts, which is below the limit. But if you suddenly switch off everything, there is more surplus solar power than you’re allowed to export. Your dedicated meter will inform the inverter, and it will immediately reduce the power, so it doesn’t exceed 5 kilowatts1.
Where Is Export Limiting Allowed?
No matter how badly you may want to export limit your solar system, it can only be done in locations where it’s permitted. Information on whether export limiting is allowed can be found here, but I am going to present the information differently for both ease of use and to make my boss think I’ve done something useful.
I have divided Australia’s regions into three categories:
- The Good: Locations where most homes are allowed to export so much power to the grid there’s little need for export limiting.
- The Bad: Most homes can’t export as much power as in Good locations, but export limiting can be used to install larger solar systems.
- And The Ugly: Here, most homes are limited to 5 kilowatts of solar inverter capacity or less, and export limiting is usually not permitted.
The information below assumes the property is on the main grid. If you can go outside and scream at the top of your lungs with no chance your neighbours will hear you, then there’s a good chance you are off the main grid and face much stricter limits on exports. Also, if you are on the main grid the amount of power you are allowed to export can still be below the limits given or even zero, depending on how much additional solar capacity the local grid can handle at your location.
Reminder: In Australia, you are allowed to install 33% more panel capacity than the inverter capacity – for example, a 10 kW inverter can have up to 13.33 kW of panels attached
The Good: In these locations, properties can usually install up to 10 kilowatts of solar inverter capacity if they have single-phase power and up to 30 kilowatts with 3 phase power. Residential properties are unlikely to be allowed to use export limiting to install even larger inverters. Still, few people will want more than the 13.33 kilowatts of panel capacity single phase homes can generally install:
- Tasmania: Under 1% of Tasmanians are on SWER lines, so the generous export limit should often be available.
- NSW’s Ausgrid Network Area: This covers East Sydney, Newcastle, and out to Merriwa.
- Victoria’s United Energy Network Area: A large chunk of Melbourne on the east side Port Phillip Bay and the Bayside Peninsula.
The Bad: Homes with single-phase power on the main grid can have up to 5 kilowatts of inverter capacity but can usually get around this limit by installing an export limited solar inverter of up to 10 kilowatts. Three-phase homes can install up to 15 kilowatts of inverter capacity or 30 kilowatts with export limiting, except in South East Queensland where special permission is required from Energex to install an export limited inverter over 15 kilowatts.
- ACT’s EvoEnergy Network Area: Covers most homes in the ACT, especially in built-up areas.
- South Australia Power Networks (SAPN) area: SAPN is the only distributor in South Australia.
- Queensland’s Ergon network area: All of Queensland on the main grid outside of South East Queensland.
- Victoria’s Jemena network area: A small but crowded chunk of North and Western Melbourne.
- Victoria’s AusNet network area: The eastern third of Victoria, not including Melbourne or French Island.
- Queensland’s Energex area: South East Queensland. Energex doesn’t automatically allow inverters over 5 kilowatts to be installed with export limiting, but currently regularly grants permission for single-phase homes on the main grid to install up to 10 kilowatts of inverter capacity with export limiting.
- NSW’s Endeavour Energy area: Western Sydney. Single-phase properties can have up to 5 kilowatts of inverter capacity, and 3 phase properties can have up to 30 kilowatts. With permission export limiting can be used to install larger systems.
- Western Australia — Horizon Power area: Regional Western Australia. Note that connections off the main grid are usually far more restricted. Also note that for new installations in WA, only residences with inverters of 5 kilowatts or less can receive the state’s low feed-in tariff.
The Ugly: In these areas export limiting may not be allowed at all.
- Western Australia’s Western Power area: Perth and South West WA. Single-phase properties can install inverter capacity up to 5 kilowatts while 3 phase properties can install up to 30 kilowatts. Only residential homes with inverters of 5 kilowatts or less can receive the state’s low solar feed-in tariff.
- Victoria’s CitiPower area: The Melbourne Central Business District. Normally single phase properties can have up to 5 kilowatts of solar inverter capacity and 3 phase properties can have 15 kilowatts. Larger inverters that are export limited are allowed on a case by case basis.
- Victoria’s Powercor area: Western Victoria, including a large portion of West Melbourne. While export limiting is possible it’s not always approved. Powercor is telling increasing numbers of households looking to install new systems in this area they will have a zero export limit.2
- NSW’s Essential Energy area: Regional NSW. On the main grid, single-phase properties can have 5 kilowatts of solar inverter capacity, and three-phase properties can have 15 kilowatts. Off the main grid, rural properties can have 3 kilowatts of inverter capacity. Export limiting generally isn’t permitted.
- Northern Territory’s PowerWater: In the Darwin region, Alice Springs, Katherine and Tennant Creek properties with single phase power can have 5 kilowatts of inverter capacity while 3 phase properties can have 7 kilowatts. Larger inverter normally only permitted if they are zero export limited.
Feed-in Tariff Lost From Export Limiting Is Minor
When a home is exported limited, all the power the solar inverter can produce is available for the home to use. So if an inverter that is export limited to 5 kilowatts is providing 8 kilowatts of power, none of it will go to waste provided the home is consuming at least 3 kilowatts at the time.
But there will often be times when the solar system will produce more power than can be exported, so some energy will be lost3.
The good news is, even in a worst-case situation, the amount will be fairly minor. If we consider a home in Sydney where no electricity is used during the day, and all the solar panels face directly north, then the percentage of output that will be lost due to a 5 kilowatt export limit would be:
- 5 kilowatt inverter + 6.6 kilowatts of solar panels (no export limiting): 0%
- 6 kilowatt inverter + 8 kilowatts of solar panels: 4% loss
- 7 kilowatt inverter + 9 kilowatts of solar panels: 8% loss
- 8 kilowatt inverter + 10 kilowatts of solar panels: 13% loss
So even in a worst-case situation for Sydney, an 8 kilowatt solar system that is exported limited to 5 kilowatts will only lose 4% of generation. While losses increase as the solar power system size goes up, even with 10 kilowatts of panels which is twice the export limit, only 13% of generation is lost.
In reality, the losses will be considerably less. This is because even if there is only a refrigerator running during the day it will reduce the losses from export limiting and if an effort is made to shift electricity consumption to the middle of the day then losses can be mostly or entirely eliminated.
It’s also unusual for a large solar system to have all the panels facing the same direction. If they face in two or more directions, it will further reduce the losses by reducing the peak solar output while stretching it out, so it lasts longer through the day.
The loss figures above are for Sydney and are affected by the climate. They’d be higher for a sunnier location such as Perth and lower for cloudier places such as Melbourne or Hobart.
Footnotes
- The inverter reduces power by moving the maximum power point ↩
- So, on the one hand, the Victorian Government is subsidising rooftop solar while on the other increasing numbers are being told they can’t export clean energy from it to the grid. This is madness. ↩
- Technically, what will happen is the inverter will reduce the solar system’s output so the generation will be forgone, but I don’t want to go into too much detail in this article. After all, I’m a big picture kind of guy. ↩
About Ronald Brakels
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Good Article. Many NSW rural situations are limited to 3Kw export, due to the length of the transmission lines. Even then, the losses from the limit are minor.
Most systems have mostly N facing panels, so really only generate peak power for a few hours a day (often 10am>2pm approx)
In my case, I have N & W facing panels, My inverters clip to 5Kw for a few hours, but I can still export a reasonable amount. I was lucky to have an early approval, so limited to 10Kw (or due to bad calculation by the approver, 8.6Kw, where he said ALL the Neutral current went down the common Neutral wire, where in fact only the difference between the phases goes down the Neutral (2 phase, 180 degree). I could not convince him that I knew what I was talking about!
One thing I find is that Voltage control works well: instead of the inverter resetting if the voltage gets too high, my inverters roll back output, so it actually helps my neighbors too because their inverters reset less often. (We are conected to a 25Kw transformer, with 5 consumers connected.)
Can I share my power excess with me neighbour?
I could easily share my excess power for the time I am not irrigating my crops.
Extension cord.
How is export limited for micro-inverters?
Hi David
If you are using Enphase microinverters — which is extremely likely — the whole system can be export limited using the Enphase Envoy gateway.
Thanks Ron. Yes I do have Enphase micro-inverters and an Envoy gateway, though not enough sunny roof to exceed 5kW, so my interest is rather academic but real. Would the gateway signal the micro inverters to shut down one at a time, or to all reduce output equally? Is this default, or would it be programmed in if the distributor required it? Can one have micro-inverter panels without a gateway, and how would that be limited?
I suspect that it is likely, that that they are all signaled equally, not in truth I don’t know for sure. But I can tell you a few things that might help with some of your pondering :- 1. There is not likely to be an Enphase system without a gateway (called the Envoy with in the Enphase system), because this is needed to setup the system, configure its profiles and report production and other important functions of the “system”.
2. While the Envoy is an important part of the system, the micros largely operate independently of the Envoy, and in a lot of cases can work without the Envoy at all. In most cases, if you had your envoy shut off, the micros would start and work on their own and independently of the envoy, and in fact of each other. Once voltage thresholds etc are configure in the profile by the Envoy at install, each micro operates largely independently. This means you tend to see panels at the end of strings shutdown soonest on voltage risk conditions, as they have the highest voltage rise being at the end of the string.
3. If you are export limited, the only way to implement that is with some sort of meter as Ronald says. In an Enphase system, that is with the Envoy-S with consumption monitoring. There are versions without this consumption monitoring (old Non -s version of Envoy and even the Envoy-S without consumption monitoring). My guess is that when the Envoy-S sees it needs to throttle due to export limits, it does this by sending the same instruction to all micros to throttle the same amount (but don’t know for sure).
4. Although my testing shows that the micros technically operate quite independently, it is important to understand, only the Envoy can provide some critical components to a properly working Enphase “System”. This certainly goes well beyond initial configuration and reporting. For example, if you are export limited, only the Envoy-S with consumption monitoring can provide this. It can also only provide this when it is running. In addition, all modern solar inverters must comply with AS4777.2015 at least. Amongst other things, AS4777.2015 has some requirements to shutdown on phase imbalance in a 3 phase setup. In a Enphase system, only the Envoy can provide this. So an Enphase setup, without a continuously operating Envoy with not be providing this functionality and likely to raise some concerns in the AS4777.2015 certification process if they did not take steps to make sure these functions are always guaranteed to be implemented. And for this reasons, I have increasingly seen that it is more challenging to run micros without the envoy which would no doubt be extra code required in later versions of the envoy to enforce implementation of various AS4777 and export limiting requirements that can’t be done in the micros alone.
I hope that helps for some insights.
To add to this, in the installer section of the Envoy’s web server control panel, you can set the profile by which all microinverters operate. I have a 14kW solar array running Enphase IQ7+ microinverters (43 of them) hooked up to the grid in a 3-phase configuration in the Endeavour Energy area in NSW, and they currently have the profile “AU default AS4777.2:2015 ≤30kVa, Vv, Vw” set. You can see from the profile name that it ensures the microinverters conform to the AS4777.2:2015 Australian standard that governs inverters, and it enables the advanced Volt-var and Volt-watt controls for adjusting export power when the grid voltage gets too high (as opposed to abruptly shutting off all export power when grid voltage is too high, which happens without Volt-var and Volt-watt). This profile also doesn’t impose any export limits, because Endeavour Energy didn’t require them of my installation (maximum is 30kW for a 3-phase installation, which my one is well under).
Now, there are quite a few profiles on offer that can be programmed into the microinverters. There are profiles that still conform the microinverters to AS4777.2:2015, but can disable Volt-Var/Volt-Watt, change the power factor to 0.9 (some grid operators require this), turn off export altogether or set specific maximum export levels like 1kW, 3kW etc., or configure to satisfy specific grid network requirements. For example, I can see several Energex profiles that do things like limit export to differing amounts, turns on Volt-var without Volt-watt, or sets the power factor to 0.9. I can also see specific profiles for other grid networks, such as Ausgrid and Ergon, that likely have specific requirements of the inverters. Finally, there are profiles for other countries that run 220-240V networks, and it’s remarkable how many of them use the older AS4777.3:2005 standard in their countries, because for many of these countries, this is the only profile the Envoy offers.
So yeah, the Envoy is essentially all you need to configure export limiting or anything else if you have an Enphase microinverter set-up.
Very true AL0126. But just note, not everyone Envoy has required bits to do export limiting. The current Envoy they will be selling is the Envoy-S. Before that was the straight Envoy which did not have the consumption monitoring / metering needed to do export limiting. Even if you have the Envoy-S, I believe at least on paper there was a “Enphase Envoy-S
Metered” and a non metered version. The metered version comes with extra current clamps to hook up to the grid side so you can do consumption monitoring and export limiting.
As a side issue for you, if you (like lots of people) have high voltages issue causing shutdown / throttling, I am not a big fan of the Volt-watt modes, as often these modes will also lower the voltages at which the throttling kicks in. I think the installers like the Volt-watt modes, because if you don’t know where to look they hid the problem at your expense anyway. They hid the problem pretty well, because they do tend to reduce the amount of shutdowns. But this is at least partially because when you throttle back output, you also reduce the amount of voltage rise you are causing on your local connection to the point of interconnect which is probably contributing to the issue. Because you don’t see the rather obvious shutdowns (or see them less), you might not notice your solar might be throttled back on a regular basis. If you don’t get under the covers and look carefully at the logs you might miss this, or think it is a cloud coming over, rather than voltage triggered throttling.
I prefer a profile that just has the voltages set to a high voltage threshold, and if I have to sacrifice V-W mode, so be it. To give you example, you will probably find the profile you mention is probably throttling from a very low 250v and will ramp down to 20% at 265v. But you will probably find that there is another setting that it will shutdown when 10 minute average voltage is a measly 255v. My AS4777.2:2015 profile allows voltages up to 265v (for short periods, and shuts down on 10 minute averages above 258v). So really apart from the requirement that the initial startup can only happy on voltages below 253v, I have no throttling until at least 285v and probably even higher. If you use a pre AS4777.3:2005 the limits are probably even higher, but you loose some other features (like frequency ramping which is probably very sensible to have if you want to be a good grid citizen), and you probably are not supposed to run those unless it is a pre 2016 install.
All these profiles need to dance carefully around the problem. AS4777.2:2015 has some rather low default recommendations, which can be tweaked up as no doubt my profile has allowed. But there is also the DNSP rules which need to be followed. But given average voltages are probably well above what they should be in lots of places, and once you factor in your local voltage rise, and pretty low values under AS4777 etc, there is not much room to play with until the distributors get the act together and deliver us power that better matches the 230v standard they are required to deliver us.
Anyway you are probably not supposed to be messing around with the profiles without agreement of your DNSP. And doing so potentially puts you running in a non compliant state. But a sub optimally configured grid sometimes forces installers into implementing setting that are probably less than ideal if the high voltage events in the grid were just occasions where there is too much generation and they do want have all generators throttle back to allow some time for rebalancing supply and demand. But I suspect for a lot of people, the vast majority of these over voltage events are simply because the networks are running out of spec voltages.
Good question about micr inverters.
I’m in the Endeavour Energy area. I have 3 x PV systems on one phase. 10kW of inverters with 11.325kW of panels. 5kW export limiter imposed on one inverter. Plus a Tesla Powerwall 2.
So, it can be done with approval.
That puts me in the good category!
I’ll upgrade the Endeavour Energy area from Ugly to Bad, since things are clearly not all bad there. Thanks for the information.
Perhaps it is worth mentioning that the stricter export limitation becomes, it will make a stronger argument for batteries. Still a very long payback period, but not as long…
Groan??
Sorry Andrew: NQR. As has been explained (and COSTED) on previous occasions batteries are VERY cost-effective….IF you stay away from the hi-tech/overpriced/dependence-creating/unproven battery-systems advocated by commercially self-interested parties. Though endless quibbling over unnecessary details might keep the presses churning, a FACT remains that I’ve been using ever-more-cost-effective batteries since 1980. I did get on the FiT in the early days for the 66cpkWh, but installed a separate system (which I have since incorporated into my stand-alone system. So-called ‘wasting’ of the extra electricity produced is irrelevant: sunlight is FREE, and whether I use it or not has no bearing on the environment. That’s a furphy from go to whoa.
Have a good christmas.
Do the inverters prevent the production of energy by the solar panels when an export limit would otherwise be exceeded? Or is the energy produced by the panels but dissipated somehow? Or is there a build up of voltage in the system?
I just don’t understand it.
The inverter reduces the amount of electrical energy supplied by the solar panels. It does this by adjusting the MPPT but instead of working to maximize power from the panels it reduces it. If you are interested you can read about this here:
https://www.solarquotes.com.au/inverters/mppt/
You could have mentioned that SWER stands for Single Wire Earth Return and why that matters. The earth is used as one conductor which has a higher resistance than a copper wire.
Aside from that, when you have high resistance lines, there is a voltage drop over their length. The distributor deals with that by putting the voltage slightly up at the sending end. But if people send a lot of power into the line then the voltage at the far end, instead of being lower than at the sending end, becomes higher. That can raise the voltage to a level dangerous to appliances.
The infrastructure is not sufficiently flexible to deal with this.
Actually I made a chart showing the percentage of electricity lines in each state that were SWER but I left it out for the sake of brevity. Then the information that was left was cut to make the piece more introductory, but perhaps all these reductions made the article like my favorite World War II movie — Abridged Too Far.
The whole system of domestic rooftop photovoltaic systems, needs to be reviewed; by both the legislatures and regulators, and, by the components (especially the inverters) manufacturers.
I have previously posted (or, submitted for posting), the proposition that what is needed, is a hybrid (not meaning in this instance, a “hybrid inverter as is commonly used) inverter that is like a cross/combination, of the Goodwe GW5000-MS inverter (or, kind of, the GW10K-MS, in terms of power conversion), and the Goodwe GW5048D-ES; three GW5000-MS provides for up to 10kW of panels generating capacity, across three MPPT’s (strings?), converting to a maximum of 5kW of AC power, whilst the GW10K-MS provides for up to 13.5kW of panels generating capacity, across three MPPT’s (strings?), converting to up to 10kW of AC power, and, the GW5048D-ES provides for up to 6.65kW of panels generating capacity, converting to up to 4.95 kW of AC power, and, acting as a battery management system and UPS, when a battery system (of up to two approved, low voltage, batteries) is connected.
Now, such a hybrid inverter, as I previously submitted as a post, as being needed, would have the capability of providing for up to 10kW of panels generating capacity, and, of power conversion of up to 10kW, to provide for up to 5kW to provide for charging a battery system, and, the other 5kW to provide for the household load and with surplus (to the household load, out of the 5kW provision) being exported to the grid.
That would provide both export limiting, and, the incorporation of a battery system (for my household, if we would have a 6.6 kW panels generating capacity system, rather than the 5kW one that we have, something like the BYD LVS 20 or 24kWh battery tower, would, I believe be appropriate), which would provide for energy arbitrage, smoothing both power exported to the grid, and, power imported from the grid, especially during peak demand periods.
Now, that would help protect electricity grids, especially, the fragile, decrepit SWIS grid, for the present.
But, only for the present.
In looking to the future, regardless of whether we like it, in spite of, and, despite, the great efforts of the WA state government, and its parent, the Australian feral LNP/ALP government, battery powered road vehicles will come to Australia, and, displace “ICE” vehicles.
And, when battery powered road vehicles with adequate distance capacity (I have read that VW expects to release a battery powered station wagon, with range between charges, of 700km, in 2023 (although, unless Australia wakes up, such vehicles will be unlikely to come to this neolithic country) ) are available, and, even for the rare ones that apparently, already exist in Australia (having not yet seen a battery powered vehicle in Australia, I wonder whether they are simply an “urban myth”, as to their presence in this backward country), when would they get charged, if people would only charge them at home?
Some battery powered cars can not be programmed to only recharge at particular times of the day, and, so, if someone drives one to work (that is, if and when battery powered cars become affordable to the working class) and home after work, then “puts the car on the charger”, the drain to the grid, that would consequently occur, during peak demand hours, needs to be covered.
As a single example, the Renault Kangoo ZE van (I think that it is the only battery powered cargo van currently available in Australia) has a 33kWh battery, and,
“To go further, Kangoo Z.E boasts a Z.E 33 (33kWh) battery,
hooked up to an energy efficient 44kW motor for a real-world
driving range of 200km depending on ambient temperature.
The 7kW charger achieves full charge in 6 hours, and one
hour of charging is enough to drive 35km.”
So, if a contractor or tradesman, using one of these during the day, or, another type of worker, gets home after work, and, plugs one of these in to charge, an immediate drain of 7 kW (I believe that it is actually 7.4 kW), and immediate significant drain is imposed on the grid, for several hours, during peak demand.
And, if a street full of these, plugs their cars into the grid, for recharging, starting the recharging between 1700 and 1800, lots of entertaining fireworks, along the street powerlines exploding.
So, the whole of the system of restrictions and available components, for domestic rooftop photovoltaic systems, needs to be reviewed, to provide for greater usage demands during peak demand hours, greater battery storage provisions (and financial assistance for householders to implement big behind the meter battery storage systems, and, regarding the fragile, decrepit SWIS grid, the allowance of large capacities of panel generation, limited export, inverters, such as the hybrid one that I proposed.
And, depending on the circumstances of each individual household, 10-15 kW of total panels generating capacity, with limiting export to the grid, to 5kW, could provide better for the months with less available solar radiation, to lessen the demand for grid electricity, peaking on a seasonal basis.
I realise that Australian legislatures do not care about the future, but, the future is coming, whether the legislatures like it or not. And, no matter how powerful, the members of the legislatures imagine themselves to be, and, no matter how trump-like, they are, they can not stop the future. A man named Canute, proved that, centuries ago.
I am on my second Tesla EV and the new one has a rage of 700km if you’re not a lead foot. I wouldn’t drive anything else.
ARTICLE WRITES: Queensland’s Energex area: South East Queensland. Energex doesn’t automatically allow inverters over 5 kilowatts to be installed with export limiting, but currently regularly grants permission for single-phase homes on the main grid to install up to 10 kilowatts of inverter capacity with export limiting.
An Update: I just had system installed 4 days ago in the Energex DNSP and suggest the above is perhaps not quite correct. I had applications rejected, and when I asked there was NO course for negotiation or discussion “its the RULES” is s synopsis of the responses.
In writing I was advised:
“As per current standards, a single phase premises is limited to 10kW generation and 5kW export. Please confirm the maximum export limit in the relevant section of this application.”
So while the article suggests 10kW inverter ( 13.33kW DC) in fact the limit seemed to be 10kW DC ( hmmm what does “10kW generation” mean exactly ?.) And yes 5kW export limit applies May I suggest an extra fact check to polish the valuable story above? is it 10kW AC or DC??
I have 13.25 kW of panels with a 9.8 kW LG Chem battery and a 10 kW inverter export limited to 5 kW. It is possible to max out the 10 kW inverter capacity with my Tesla, house load and Heat Pump hot water. As the LG Chem battery charges using DC current from the panels it is possible to go over the 10 kW inverter limit by charging the LG Chem battery in the middle of the day. I have seen my panels producing over 13 kW of power when the battery is drawing 3 kW DC power and the battery, house and car 10 kW of AC power.
House batteries should have the capability of being set to turn off when they are fully charged and then on towards the middle of the day. As batteries currently operate they charge from power in the morning that could otherwise be sold rather than from power that may not be able to be sold in the middle of the day. Website link shows system producing well over 10 kW.
I was always of the belief that a 5kW inverter limited the total output/ production from my 6.5kW solar system to 5 kW, irrespective of what is being used in the house. Thus if my system is at maximum output, and I am using 2kW, only 3 kW is being exported to the grid. Am I wrong?
That is correct. A 5 kilowatt inverter will never supply more than 5 kilowatts of power no matter how many kilowatts of panels it has. But if you had a larger solar system with a larger inverter that was export limited to 5 kilowatts it could potentially supply 2 kilowatts to your home while exporting 5 kilowatts to the grid.
It ‘clicked’, not long after I wrote the comment
My 10 kW system will not go above 10 kW unless my house battery is charging and then it can go to 13.25 kW. See image at http://www.johnrogers.com.au/battery_charging_noon.jpg
CORRECTION: My 13.25 kW system will not go above the 10 kW inverter limit unless my house battery is charging and then it can go to 13.25 kW. The battery is charging from the DC current which is before the inverter. See image at http://www.johnrogers.com.au/battery_charging_noon.jpg
I’m glad to hear it’s flexible enough to do that. What inverter do you have?
I think is is utter madness that the VIC government is handing out generous rebates of $1850.00 and 4 year interest free loans of up to $1850.00 and Powercor has zero feed in capacity for excess solar power. I have solar on my house and having it installed at an investment property, but not sure what to do now as there will be no benefit of feed in tariff.
Below is the email response I received from Powercor.
“If your solar company provides you with the Solar pre-approval (SPA) number for your pre-approval, we can check specifically what was decided on with regards to exporting. Generally however, I can advise that Powercor intends to upgrade the network over the next 5 years, starting in January, however, the specifics of where upgrades are happening and the order has not been decided. That said, provided the Installer included your details and phone number in the customer section when the SPA was lodged, the solar team intends to follow up with customers if capacity becomes available to export into the grid through upgrades to the network.”
I can’t see any reference to the NT. Do you know the situation here?
According to NT Power and Water they will normally allow up to a 5 kilowatt inverter with single phase power and up to a 7 kilowatt inverter with 3 phase power. It’s only possible to go larger with a zero export limit:
https://www.powerwater.com.au/customers/power/solar-power-systems/pv-class-requirements
I will update the article with the information.
Hi i want to install solar with no power
going back into the grid with no batteries.
is there a inverter that stops power going back
and only supply me with power from the grid
at night or not enough at day time ?
Definitely, that’s an inverter that is export limited to zero. But you may as well just get a standard inverter and send your excess electricity into the grid. It’s moderately cheaper and the solar feed-in tariff you’ll receive will lower your electricity bills and increase the amount of clean energy available for others to use.
Essential Energy area. 3-phase.
11kW panels with 10kW 3-phase inverter (Fronius Symo + Fronius 3-phase meter).
Export limited to 3kW/phase.
essential enrgy in central west nsw (Orange) are generally restricting to max 5kw export limit regardless of 1ph or 3ph: 2 x 3ph residential applications approvals cutnpaste below – only difference was one specifically stated APPROVAL/SITE SPECIFIC CONDITION(s): Total Site to be export limited to 5kW 3 phase 1.66kW/per phase (and the padmount sub for the subdivision in on the property boundary)
(2nd one APPROVAL/SITE SPECIFIC CONDITION(s): Total Solar Export must be limited to 5kW). both said –
A condition of this basic connection offer is that all inverter energy systems must have the volt-watt and volt-var response modes enabled with the following settings:
Voltage (V) – measured at inverter terminals
P/Prated (%)
207
100%
220
100%
253
100%
260
20%
Voltage (V) – measured at inverter terminals
VAr (var % rated VA)
207
44% leading
220
0%
240
0%
258
60% lagging
The percentage var/VA level leading is the inverter sourcing vars to the grid, whereas the percentage var/VA level lagging is the inverter sinking vars from the grid. Furthermore, the sustained overvoltage inverter protection set point shall be set to 258V.
Has the oppressive authority in WA ever given a reason for not allowing export limited inverters in WA?
I realise that all the political parties in the the WA state parliament and especially, the Synergy/Western Power conglomerate, that controls approvals of domestic rooftop photovoltaic systems connected to the SWIS grid, are opposed to domestic rooftop photovoltaic systems (even though we stabilise and sustain the grid), but, I am wondering whether any reason has ever been given by the oppressive authorities, for banning export limited inverters in WA.
This could be important, given that we have a state parliamentary election due in a couple of months.
After (almost) three months with no reply, has any reason been given, as to why export limited inverters are not allowed for single phase grid connections to the SWIS grid in WA?
Also, given that export limited inverters (supposedly) work the same, regardless of the grid to which they are connected, why is it so, that states have different rules whereby some allow export limited inverters, and, some do not?
I am not sure whether it has been explicitly explained, but, what exactly, is the limit of panels generating capacity, that is covered by the federal solar panels rebate?
Is it the 6.66 kW, as the 1.3 overload factor of a 5kW inverter, or, is it the maximum allowed (by the manufacturer) panels generating capacity, for an inverter that is allowed by a state/territory government?
The reason for this query, is that, in the past, my understanding has been that, in WA, where export limiting is apparently, banned by the gratuitously oppressive state parliament, and, where a limit of a 5kW output inverter, is allowed, for a single phase grid connection on the SWIS grid, a limit of 6.66 kW of panels generating capacity, is imposed for single phase connections to the SWIS grid, and, thence, the limit of panels generating capacity, to which the federal solar panels rebate applies, for such a connection, has been the 6.66kW.
But, now, Goodwe have the GW5000-MS inverter, which, from what I have read, is apparently allowed in WA, for a single phase SWIS grid connection, and, that inverter is a 5kW inverter, that has a maximum panels generating capacity;
“Max. DC Input Power (Wp) 10000”, from its published datasheet.
Thus, the question arises; if a single phase domestic rooftop photovoltaic system, involving a Goodwe GW-5000-MS inverter, and, 10kW of solar panels generating capacity, is installed (across up to three MPPT’s), would the federal solar panels rebate apply to all of the 10kW of solar panels, or, to only the first 6.66 (or whatever is the exact applicable quantity) of the solar panels generating capacity?
This is assuming that my understanding of what I have read, is correct; that such a system would be permitted, in a single phase connection to the SWIS grid.
Whilst this may not be technically defined as “export limiting”, as the inverter specifications, specify that the inverter, whilst allowing up to an overload factor of 2, will only generate up to 5kW of A/C power
(
“AC Output Data
Nominal Output Power (W) 5000”
)
it is, kind of, effectively export limiting.
.
STCs can be received for panel capacity up to one-third greater than the inverter capacity. Because people have been refused any STCs for being just a few watts over, no installer will go over the limit for a normal installation. There are exceptions for off-grid installations and systems that are installed with a battery. Installers must also follow the recommendations of the inverter manufacturer and they may say the limit for panel capacity is less than one-third more than the panel’s capacity.
I’m in regional WA with a rural 2 phase supply. I am trying to get a system installed (6.5k smart hybrid inverter with a battery) and have been told by Western Power that I am limited to a 3.0 kva system. The installer has been able to get the system through WP in the past as the inverter can limit the export to grid to 3kva. However they have been advised that this won’t be allowed anymore. I was really keen for this system with a battery as most of my power is used at night and I like the idea of power during blackouts, which do happen quite a lot here. Any ideas of how I can get a system that is actually going to generate enough power to charge a battery?
Hello Kiki
I am afraid Western Power is very strict. If you can export 3kva that means you can have a solar system with up to 4 kilowatts of panels. Despite the low feed-in tariff you will receive it can still be worthwhile, especially if you can shift some electricity consumption to the middle of the day.
While I don’t know where you are a 4 kilowatt solar system should produce an average of around 18 kilowatt-hours a day in WA. This is sufficient to charge a battery, although larger solar systems generally improve the return from batteries. But I will warn you, even with the high cost of grid electricity and the low solar feed-in tariff in Western Australia, batteries normally won’t pay for themselves. If that doesn’t worry you then you can get a battery and just hope it mostly pays for itself. Or, if you want a lower cost method of dealing with blackouts, you can get yourself a small generator.
This seems to be becoming a big problem at least locally. I live in Warrnambool, Victoria.
We have had solar for 6 years and just recently moved homes. The new home didn’t have solar. We just applied for pre-approval from Powercor and were given a 0kW export approval which is going to make almost anything we choose uneconomical. The Solar installer is telling me that they just started getting 0kW approvals back for about 9 out of 10 requests and so they don’t believe they will be able to do many installs at all going forward. So basically the whole local industry is going to be cactus until this is resolved. I’m surprised this hasn’t hit the mainstream media yet.
It seems so strange that it is clear government policy to get more solar going and yet the network operators are effectively blocking it now.
Interesting article. We are on a zero limited export. I guess it would be technically possible to have a solar system with a battery but still be connected to the grid as backup. Economically this probably Is not viable, as our electricity bill is fairly low. We might still be willing to do this all the same, from an environmental viewpoint.
A small solar system can be financially viable. But if you don’t use much electricity it may need to be very small, as I explain here:
https://www.solarquotes.com.au/blog/zero-kw-export-solar/
At the moment a battery system is unlikely to pay for itself, but you could install a system that is larger than what makes financial sense for your current situation and hope home batteries will fall in price over the next few years. Of course, if you are planning to get an electric car, that has the potential to make a huge difference to your self consumption of solar power.
Are Tesla Powerwall smart enough to let majority of power export to grid and only start charging battery as inverter approaches it’s export limit?
No unfortunately. So having a powerwall is way less useful for helping with an export limit than you would think.
This is disappointing as this would be an easy option to implement.
I am a total newbie to this but I am unclear why export limiting is good? Surely the distributors capping what you can export to the grid is a bad thing? Means that it caps the amount you can reduce your bills for power used outside of daylight hours? So the size of the system becomes irrelevant if you can only export 3kwh (we are Regional NSW – Essential Energy).
What am I missing? Sorry if dumb question.
Hi Nicola
The fact that export limiting is necessary is not a good thing. It would definitely be better if we didn’t need to limit the amount of power solar systems sent into the grid. But, if you are living in an area where it is required to install a large solar system — a situation around half of Australians are in — then export limiting can allow a larger system with normally very minor losses of clean solar generation. So it is unfortunate that it is necessary, but good that people can still install a larger system and generally have insignificant losses.
Thanks Ronald! Makes sense but begs my next question (sorry). If you can’t store the power (too expensive) and you can’t export it, why the requirement (or desire) to put in large systems?
If a home can’t export any power at all then there is no financial reason to install a large solar system. Instead the home can benefit from a small system, as I explain here:
https://www.solarquotes.com.au/blog/zero-kw-export-solar/
Ah yes I see. Thank you. I’m trying to get some unbiased advice on whether or not we should add more solar. We have a 3kwh system and are really using as much during the day as we can. About 50%. I can’t justify the cost of adding additional solar if the max I can export with Essential energy is 3kwh. Even if I were exporting 100% of it, it still would only bring down my bills by a tiny amount per month. But still the solar companies keep trying to sell it to me…..
The good news is, if you had a total of 6.6 kilowatts of solar you’d probably loose very little due to export limiting if you consume half the output of a 3 kilowatt system and can export 3 kilowatts. But whether or not extra solar capacity will pay for itself is another matter. Normally it makes more sense to buy a second, separate system, than to expand an existing one. This gives the advantage of having a new system covered by a new set of warranties. So you may decide adding a second system is worthwhile, or you may want to put it off until your current system develops problems and replace it with one large new system. Our Solar & Battery Calculator can give an idea of if it’s likely to pay:
https://www.solarquotes.com.au/solar-calculator/
But your situation is complicated by already having a 3 kilowatt system. If you’re not satisfied with what answers our calculator gives, let me know your figures for grid electricity and solar feed-in tariff and I’ll come up with an estimate for you.
As discussion of the topic of export limiting, is continuing, what,if any, is/are the direct effect differences to electricity grid load (as in the load on the wires, not the “load” as the term used for meaning demand), between a 5kW inverter, and a 10kW inverter with 5kW export limiting?
Similarly, which would be more detrimental to a fragile electricity grid, through power exporting; a 5kW inverter with no export limiting, or, a 10kW inverter, with export limiting set to 1kW?
Ronald
I’m on a swer line in rural south Australia. SAPN has told me I can’t have more than a 5 kw inverter , but that’s just not enough. I want about 10Kw of panels so I can run pumps etc. How do I get around this with SAPN , am I allowed to export limit on a swer line in Sth Aust. I have spoken to one installer , but he couldn’t really help me . Thanks Steve 0418 815 193
Hello Steve
Unfortunately, SAPN won’t allow more than 5 kilowatts of inverter capacity on an SWER line. (Although they will also allow an additional 5 kilowatts of battery inverter capacity.) You could approach SAPN and ask for special permission to install more solar capacity on an SWER but I would not be optimistic about that. An option is to take your pumps off-grid and run them independently off a separate off-grid solar system. If your pumping needs are large enough this can pay for itself, but it will be expensive to set up. (Or at least it will be expensive to set up well. People have done it at fairly low cost with second hand panels and a DC pump.) If that’s not a good option, you can consider getting a demand tariff and doing pumping outside the peak period when the cost of grid electricity will be relatively low. But you’ll need to be confident you won’t be hit with high demand charges during the evening peak that will wipe out any advantage.
I am a bit confused about export. I installed 6.6kw solar panels and have Goodwe 5kw inverter and applied for export limit of 5kw. Just last week, Powercor (Western Victoria) advised that they now have more room in the grid for export.
I was told to set Power Limit to ON. And Set Power Limit to 100%. Is this correct?
My sister has the same type of inverter (Goodwe) but she lives in the Estern suburbs of Victoria and she has been exporting but her Power Limit was set OFF.
Why my Power Limit is set to ON with the % whereas her Power Limit is set to OFF and she has been exporting.
Thanks
Hi Andy
I am surprised to hear that Powercor has allowed you to increase your exports, but that is good to hear. The reason why your sister’s inverter is different from yours is your Goodwe would be because yours has a current transformer device that lets it limit the amount of power it exports to the grid. As your sister can presumably export as much power as her solar inverter can produce it wouldn’t need this device.
Hello. I have a new residential PV system in Perth WA, 6.6kW total panel capacity and a 5kW inverter (Growatt Min 5000TL-X). I do NOT have a device in my meter box that could tell the inverter anything about consumption and feed in energy. I am not even sure the inverter would support that, but I fear that sadly up to 25% of the PV energy might be going to waste!
Unfortunately, the inverter’s parameters such as Export Limitation are all password protected, and so far I have been unable to even determine who knows this password. I believe it must have been set up during installation, but the installer company claims that this is handled by Growatt themselves. I have not been able to get an answer from Growatt Australia yet, it seems there is a bit of a cover-up going on.
So, I am pretty much left in the dark about whether all the energy my panels are theoretically producing is being utilised, or (which is my fearful assumption) up to 1.6kW are wasted whenever the panels produce more than 5kW AC.
I don’t quite understand how the DC energy from the inverter can go to my home circuits “first”, before any “excess current” is fed into the grid. This seems technically impossible, because there’s only a wire going from the inverter to the meter (the export or feed in to the grid) and a wire going from the meter to my home’s main fuse. Certainly this dumb meter is not capable of sending current from the inverter selectively to my home circuits and any excess to the grid?
My assumption is (and I may be wrong after all) that the idea of using my own energy first before buying from the grid is an illusion, and in fact it only appears like that because all the energy from the inverter (up to 5kW) is measured as exported, all energy required by the house is actually imported from the grid (as if there was no solar system at all), and it is just because the exports are offset against the imports for billing, why it appears that my PV system is “reducing” the imports.
Can anyone shed any light for me? Have I been conned into believing I could produce up to 6.6kW myself, but in fact the maximum my inverter will ever allow through to the meter (and to my house) is only 5kW? Is this perhaps one of the well-kept secrets about the reality of residential solar production in Western Australia, one that neither the solar installers or inverter manufacturers, let alone Synergy or Western Power want to be publicly known?
No-one seems to have replied Dirk, so I will try. First read the section “How Export Limiting Works” at the top of this thread. Your meter is on the connection between the mains network on one side and the combination of your inverter and your loads on the other side. So what goes throgh the meter, in either direction, is the difference between what you generate and what you use. Providing the export limiting is done on the meter current as described above ( not on the inverter output current), you can generate more than the export limit if you are consuming enough power to make up the difference between generation and export limit. Export limiting does limit the inverter output, but only as needed to keep the export power below the limit. The word “first” can be confusing. No active system controls whether you use inverter of imported power. It is just the placement of the meter and the current sensor that controls the limiting.
Hope that helps,
David
Thanks so much, David.
I think I was partially wrong about how my PV is connected to the home and the meter. It appears the wire from the inverter is directly connected to my main fuse for the house circuits. Since in WA you can’t have more than a 5kW inverter on a private residence, I believe there isn’t actually export limiting in play, and the inverter itself clips the output AC regardless how much the panels are generating, sadly. So far I have not seen much more than 5kW DC anyway, but in summer I would expect to see a curve that’s flattened at the top during the high sun phase, as it is cut off by the inverter.
I still don’t know if they have programmed the inverter to reduce the overall output by a percentage or not. I also don’t know if my meter has limiting but suspect not as it is a pretty dumb device.
I think it is illegal in WA to rewire your inverter or modify any parameters, as it may result in more than 5kW being sent to the grid, so I will just bite the bullet and see that I use as much solar as possible.
We just had a 30kW inverter solar install for our business and it has been limited to 1.8kW export. While this is fine during the week when we are open, it seems a huge waste of electricity on the weekends when we are closed.
Is there anything that can be done about it? We are in an area where only about 20% of the homes have solar.
You could buy a battery, charge it on the weekend and export during week nights. But you probably would not recover the cost of the battery within its lifetime.
Talking of which, the fact often gets dropped under the table that neither batteries nor panels and inverters (being mechano-electronic devices) have a limited life span, and their efficiency deteriorates gradually after only a few years. Of course the manufacturers don’t want this to be public knowledge and pretend that once you paid for a system you are set for life (yours, not that of the system). As such, unless the investment pays for itself within at most 5-6 years, IMHO it is not a good investment/waste of money and natural resources. Regarding batteries, as we all know from our mobile phones, constantly being charged and discharged, will deteriorate much quicker than PV panels (and the same that goes for phones, laptops, and your electric toothbrush also goes for solar and electric vehicle batteries, unfortunately). Efficiency has and will improve further over time, but never to the point of perpetuity
I’m afraid that’s a tough situation. While there are some energy management measures that could help around the edges, I can’t think of any good solutions for the typical business.
Hi everyone,
I got a question about export limiter that I hope to get some answers from the community.
I have an existing 3.5kW PV system with Solis inverter. I am looking at adding a second system (6.2kW) with GoodWe inverter. given that we are working from home all the time these days. I was told that as there is an export limit of 5kW and I already have 3.5kW system, my new system will be export limited to 1.5kW.
To me it does not quite make sense as no system can produce 100% of its capacity meaning my existing 3.5kW will never produce full 3.5kW (on a good day, I am lucky to get 2.5kW). so if I was correctly explained to, then I am limited to export less than 5kW (because my existing system will never produce 3.5kW)
No installer (or their salepeople) is able to explain to me how the limiter is connected/set up in the scenario where I have 2 inverters. I think that the limiter can connect only to one inverter and not two at the same time
Does anyone know how the limiter works in this scenario with 2 inverters?
Good question Tony.
I’m in the same situation, except I have an existing 5kW system.
Will this mean any additional system would be limited to 0kW output??
I haven’t made any applications yet, but I’ll certainly be asking this question when I get quotes!.
If so, it would make replacing the whole system more viable… which is exactly what I wanted to avoid (and such a waste!)
Hi Everyone,
just wondering if anybody can shed some light on the following,
I have a 5kw solar system plus a Tesla powerwall 2 on my house .
At the time of the powerwall install I also had the Gateway installed at an extra cost so I could keep using the generated power from the powerwall and during solar production when the powergrit fell out without danger for the grit workers because the Gateway instantly falls and prevent power to the grit.
So in effect I have two safety guards in place, 1. the 5kw limiter to the grit and 2. the extra Gateway .
My question is should that then eliminate the 5 kw inverter of the powerwall wich Energex claims is part of the 10kw allowance on a single phase?
Hi All.
I have just had a 6.6kw system installed with a Fronius 5kw inverter and am export limited to 3kw.
I have noticed that one string seems to be performing well under the performance of the slightly smaller string. At times MPPT1 is at 600 odd watts while MPPT2 is at 2500 odd watts. MPPT2 always shows better performance than MPPT, usually quite significantly better. So my understanding of the info above is that my inverter will increase production in unison with demand until it hits 5kw? If that is the case it seems counter intuitive to me as I don’t know if demand will outstrip production until I actually turn the appliance (eg A/C) on and check the display. Wouldn’t it be better for the inverter to display it’s total actual potential output under current conditions?
Hi John
I’m afraid in a typical situation the inverter won’t show its potential output. So if your home isn’t currently drawing power you won’t know from looking at the display if it’s capable of producing the maximum 5 kilowatts or if it can’t provide more than 3 kilowatts. All I can really suggest is to try to shift power use to the middle of the day and hope mainly solar energy is consumed.
But, if you are really keen, I suppose you could use a site such as PV Institute’s Live PV Map to see how other solar systems in your general area are performing:
https://pv-map.apvi.org.au/live
Note that patchy cloud can produce a lot of variation in output.
Hi All,
Great article and content on this website ?
I have a 10kw Solar Edge inverter limited to 5kw. Self confessed newbie to the mechanics of Solar so bear with me. In my mind though the Smart meter at the box would adjust the export limit in line with what the house is consuming? IE if I’m producing 8KW, the house is using 2KW it will still export 5kw? Solar Analytics confirms in this scenario it’s only exporting up to the limit; 3kw. Was sure if it’s been configured correctly or if this is just how it works?
Of more concern is occasional spikes in consumption which go past the 5kw limit. The data has 5KW flat lining confirming more is being generated. These consumption spikes go past the Solar energy being limited suggesting we’re drawing from the grid! ?
Worried the impact this will have currently when we charge an EV in the near term
When it says that you can export 5kw, does that mean you can export up to 5kw PER HOUR?
Shane, you appear to be mixing up kW and kWh – easily done!
All is explained here: http://www.solarquotes.com.au/blog/kw-and-kwh-what-is-the-difference/
( 5kW per hour is a non-sensical unit unless you want to describe an acceleration of energy!)
Finally understand, the article above is very well written for the layman
Thanks
I think of it like the rate at which water is flowing out of a hose. 100 litres alone means little, but if there are 100 litres per hour, this means 100 “litre hours” of output. It’s the same with kW and hours of solar electricity production. 5kW times the number of hours is the total production over that time.
When it comes to the limiting imposed by the electricity companies’ feed-in regulations, it means that, at any one time, not more than 5kW (100L) maybe be output to the grid (hose), it has nothing to do with the total over a certain period of time.
WA has just legally forced the installation of inverters, which can be switched off altogether as my son has just found out. Am lucky as mine will only switch off once voltage goes above 253VAC (?) and that has only ever happened once. FIT is about 2.25 cents/kWh or 10c after 3PM and normal tariff is 28 cents.