In just over a week, Victoria’s Emergency Backstop Mechanism (VEBM) requirement for rooftop solar systems comes into effect. Here’s what’s happening, why and how much it might cost all electricity customers.
Why An Emergency Backstop For Solar?
Uptake of home solar power in Victoria is still progressing at a rapid clip. More than 770,000 small-scale PV systems have been installed across the state to date, with over 36,000 installations this year so far. The surplus electricity exported by these systems helps push down the price of wholesale electricity during the day, which benefits all Victorians whether they have solar panels or not.
For example, at 10.35AM yesterday in Victoria, the wholesale spot price was -$44.00 per megawatt-hour. At that point, rooftop solar alone was contributing 31.8% to the state’s demand (Source: OpenElectricity – formerly OpenNEM). While demand was comparatively low given it was a Sunday morning, rooftop PV was meeting up to 50.9% of demand (Wednesday afternoon at 1pm) over the last week.
Managing all this solar energy goodness presents some challenges to grid operators. Among them, the potential for minimum system load (demand) events coinciding with high solar exports threatening network stability.
The Victorian Emergency Backstop Mechanism is intended as a last-resort method for avoiding potential blackouts and electricity infrastructure damage.
How Does The VEBM Work?
The VEBM allows the state’s Distributed Network Service Providers (DNSPs), after direction from the Australian Energy Market Operator (AEMO), to temporarily curtail or switch off solar power systems remotely.
The sequence of actions in such an event:
- Reducing or disabling exports – a solar household will still have access to their self-generated electricity and to mains grid supply.
- If network stability issues continue, systems may be turned off – mains grid supply will continue.
- An “all-clear” signal after the event passes and normal system operation/exports can resume.
To trigger such actions, a signal is sent to the solar inverters of systems. To receive and act on these signals, an inverter must support Common Smart Inverter Profile Australia (CSIP-AUS) and be internet-connected.
When And Who?
Originally, rooftop solar systems below 200kW capacity installed or upgraded1 after July 1 this year needed to be emergency backstop compatible and enabled, but the deadline was extended to October 1, 2024 – next Tuesday.
The requirement does not affect systems installed before the deadline, but if you’ve had an installation since March this year under Victoria’s solar panel rebate scheme, it will very likely be CSIP-AUS compliant. This is due to a requirement introduced for the Solar Homes program to make systems ready for flexible/dynamic exports2.
Even where an internet connection isn’t available, a CSIP-AUS compliant inverter is still required. These systems will be subjected to a lower fixed export limit.
How Much Will It Cost Electricity Customers?
The National Electricity Rules allow for distribution and transmission network service providers to apply to the Australian Energy Regulator (AER) to adjust allowed revenues if eligible changes in costs are incurred during a regulatory control period.
Jemena, Powercor and United Energy submitted applications to recover costs related to the VEBM, and the AER delivered its decision on Friday. The AER determined the networks incurred materially higher costs as a result of the emergency backstop requirement.
After making minor modelling adjustments reflected in its approved pass-through amounts for all three networks, the AER says the average annual electricity bill impact for residential customers in the 2025–26 regulatory year is expected to be (nominal amounts):
- Jemena: $10
- Powercor: $7
- United Energy: $6
Initiatives such as VEBM and flexible exports not only help protect Victoria’s electricity network but also allow for increased rooftop solar capacity to be installed. This enables even more households to directly and indirectly benefit from PV and further reduces the need for burning emissions-intensive brown coal for power generation.
More information on Victoria’s emergency backstop mechanism for solar can be found here.
Footnotes
- Where the upgrade involves a new inverter, or an inverter replacement not performed under warranty with like-for-like. ↩
- Powercor has signalled the introduction of flexible exports soon-ish ↩
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How does the technology work?
Does it require an internet connection? If so what happens if you don’t have an internet connection, or the network goes down?
It requires an internet connection. If the inverter loses its internet connection (for example either the internet goes down or your router password is changed) the inverter sits at zero-export until the internet is reestablished.
A very large percentage of inverters are made in China
A lot of malware has been found hidden in products from this region not to mention all network (internet) connected devices are sending you their current and historical PV output information on an app that is connected to a cloud based in China so we have given direct access to our energy grid to a foreign government has anyone looked at the software on these inverters ?
When the backstop was introduced in SA, one of the highlights for PV owners was the lift of the export limit from 5 to 10kw.
Will this be happening in Victoria?
That was ‘Flexible Exports’ (1.5 – 10kW export limit) which is different to the ‘Emergency Backstop’ (zero export). Confusing I know.
The Emergency Backstop in SA, depending on how it’s configured will either shut down the inverter via a smart meter contact or put the inverter into zero-export via an internet command. It is claimed this will only be used in a grid emergency
Flexible Exports in SA will keep your inverter at a 10kW export limit by default, but SAPN can throttle it down all the way to 1.5kW to manage the grid in their day-to-day grid management.
Quite a number of us in SA sat at zero export for the whole weekend due to some fault in this system. Affected Fronius inverters with Fronius smart meters
SAPN believe it was a problem at Fronius, can you obtain any more information?
Thanks for the clarification, I wonder if this will be introduced in Victoria.
If Ausnet has a day, then it probably won’t be. I read the response to the original paper on the backstop, while every other stakeholder was happy with the export zero command, Ausnet wants full control, to force people to import instead. I’m a bit annoyed about that, being I live in ausnet domain.
Hi,
First part is OK:
“Reducing or disabling exports – a solar household will still have access to their self-generated electricity and to mains grid supply.”
But this:
“If network stability issues continue, systems may be turned off – mains grid supply will continue.”
Why would they need to cut my solar off if it’s not exporting?
b0b
I live in queensland which has one of the largest uptake of solar.have not seen any decrease in my power bill.yet this is one of the reasons we have got to go solar to reduce what people pay.i know some people who are getting 44 cents a kWh this is way above market value so how can your power bill drop at that price.
Hi Phillip,
The people who get 44c/Kwh are on a legacy feed in tariff. They got that long term incentive because as early adopters they could have easily paid $12,000 per kilowatt of system capacity. The people that went first offered capital to build industry capacity and helped drive prices down for those who followed.
These days you’ll get more than ten times the bang for your buck. 1kW systems that produce 4.5kWh/day are being replaced by 13.2kW systems producing nearly 60kWh.
The best thing now is to consume your own power for free during the daytime. Heat water and charge your EV so you have no petrol bill and as a country we’re not exporting billions upon billions every year to buy 90% of our transport fuel in from overseas.
Why is extra complexity required?
If the inverter voltage limits are set correctly, ohms law will determine the power generated by a house will not travel very far from home.
My surplus may go to my next-door neighbour, but it won’t go past the next person up the line with solar on.
Thus, the power output of household solar will automatically adjust to keep the voltage stable and supply the local demand.
As well as grid connected solar, I have two off grid systems. One on essential services of the house and the other in my caravan.
The output of these inverters is stable, regardless of load.
I see remote control as a cynical exercise by big business to determine who is allowed to export power.
David Taylor, Rowville, Victoria.
I have 6.6Kw since 5 years now, with a Fronius 5Kw inverter. I now have opportunity to increase my array upto above 13Kw. What would be the adjustments to my system, to effect this upgrade. My system was installed by Solar Dynamics ( great service)
Regards, David
Hi David,
Best contact Solar Dynamics but I would assume you need a Fronius Gen24 Primo 5kW (you’re on a single phase?)
With a BYD battery installed, 13.2 isn’t a limit anymore, so you may even be able to expand both inverters to 7.5kW of solar each
Many thanks for your prompt, response. For clarity, does not the inverter need to be replaced with a compatible inverter ( say 10Kw), or are you suggesting a second inverter (5Kw) to compliment the additional panels on my carport, regards, David
Hi Dave,
It’s a bit hard for me to recommend from this distance sorry, best get an installer to visit and quote you on some hardware. If you have an old inverter it may need replacement, if you have 3 phase it may mean you need more than one inverter to balance output.
https://www.solarquotes.com.au/blog/upgrading-vintage-solar/
https://www.solarquotes.com.au/quote/start/
Again, thanks
I have just read this article in The Guardian:
https://www.theguardian.com/australia-news/2024/dec/07/smoke-detector-risk-power-shutdowns-blackouts-solar-power-grid
It claims that energy providers already have an emergency backstop mechanism: they send a voltage spike (260V?) down the wires and this trips older style inverters to switch off. The article points out the risks of this. I assume that hundreds of owners have to (somehow) manually restart the inverter after such an event.
Have I read this correctly? Would a Tesla Powerwall 2 be affected?
Hi Michael,
Modern inverters throttle at 5% per volt over 253vac. They shut down immediately at 263 or if they see 258 for 10 minutes straight. However they reset themselves immediately.
I wrote a bit about it here :
https://www.solarquotes.com.au/blog/sa-off-grid-renewables/