You can partially power your home with a grid-connected solar panel system during a blackout without a battery. Here’s how it can be done.
One of the important safety features of a grid-connected PV system is when the grid is down, the system’s solar inverter will shut down too. If systems continued to export electricity to the mains grid during a blackout, this poses a major risk to workers attempting to fix the grid and could damage grid hardware. This safety feature is called anti-islanding.
To have access to electricity generated by your solar panels during a blackout, usually what’s required is an energy storage system. However, this isn’t always the case – for example, if you have a Delta E5 inverter.
Who Is Delta?
Founded in the 1970’s, Delta is a Taiwanese electronics manufacturing company. It’s probably best known in terms of solar manufacturing for its inverter products, but it has also moved into battery storage. SolarQuotes’ founder Finn is a fan of Delta, mainly due to his experiences with Delta hardware when he worked as a control systems engineer in a nuclear power plant in the UK many years ago.
“We used Delta power supplies from Delta Electronics,” says Finn. “I’ve always been very confident Delta as a company can make reliable electronics. What they’re not very good at is consumer-level marketing.”
Let’s call Delta a quiet achiever – and one of those achievements is built into its E5 inverter (5kW)1, which is listed on SQ’s hybrid inverter comparison table.
Delta E5 “Stand Alone” Mode
When the Delta E5 hybrid inverter loses grid connection, it goes into “Stand Alone” mode. The ATS (Automatic Transfer Switch) inside the inverter cuts any energy exports to the grid and only supplies the critical load circuit. Once a load is applied, the CT (Current Transformer) inside the inverter recognises the load requirements, converts the DC from the solar panels to AC and supplies exactly what is needed to the appliance/s. The E5 has a built-in CT clamp measuring the loads as they rise and fall.
Here’s a video showing the E5 it in action. It’s impressive stuff.
The feature won’t be much use to you at night or during extended periods of heavy cloud, but for those wanting to avoid plonking down a big wad of cash on a solar battery system and still have some blackout capabilities, the Delta E5 could be a good option. For example, a fridge/freezer could be run through the day to get through the night and the same goes for recharging battery powered lights, laptops and handheld devices. You’d just need to be careful in what loads were applied and keep an eye on the weather.
Being a hybrid inverter, the Delta E5 is ready for a battery should you choose to add one in the future. The cost of the E5 is around the $3,000 mark.
Also on the horizon is the Enphase IQ8 microinverter that will have stand-alone functionality. Enphase isn’t as modest as Delta, so we should be hearing plenty more about that soon.
Footnotes
- A 6.6kW solar power system is a good match for a 5kW inverter – learn more about oversizing ↩
About Michael Bloch
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A less expensive option is a small gen set for the essentials and a properly set up change over switch. Managed this way through the aftermath of both a cyclone and the Brisbane storm a couple of years back, works through the night.
Yeah, notwithstanding the power tends not to go out unless there has been some lightning, which usually comes with clouds…
It’s a pity the E5 wasn’t available when we bought our 5kw system 5 years ago for AU$10000.
I thought about installing a contactor to isolate from the mains, and powering up the solar inverter with a small generator, or even a UPS. But I doubt the inverter would regulate the output automatically.
We also have far fewer power outages over the past few years.
what can be done if one has microinverters on each panel?
If they are the – soon to be released – Enphase IQ 8 ‘Ensemble’ microinverters, then you can grid form just like the Delta. If they are older microinverters, you lose power with the grid.
This is a good example of what is wrong with the state of solar technologies today, so many bits an pieces that might work to achieve limited ends. It reminds me of the state of audio visual technologies in the 1970s and 80s,. This domain is still not settled as anyone who has been to a few presentations in the recent past involving microphones and laptops.
Thats because of evolutions and improvements of solar hardware.
I’ve just had a quote from a local company and the guy has told me that the Enphase IQ7 will have this capability next year with a software update. Is this true or would i be looking at replacing IQ7’s with IQ8″s?
Only if you have an equal number of IQ8s installed also per Enphase‘s info so far. Otherwise the IQ7s will still lose power. So you would only have to replace half your IQ7s with IQ8s and install their isolating relay to isolate your house from the grid (~$2000 USD + whatever the IQ8s cost).
I think that anti-islanding protection shouldn’t be installed in hybrid inverters. It should be part of energy meter which is supplied by grid energy provider (the same company which should be interested in protecting their employes with anti-islanding “feature”). During the grid power outage the energy meter should simply disconnect local installation from the grid and the hybrid inverter should keep working. Thanks to current idiotic implementation of anti-islanding I don’t see any reason to buy hybrid inverter.
So, is there any significant functional difference between this Delta E5 inverter, and the Goodwe GW5048D-ES inverter?
Here is a brochure with specs for the Delta H5A inverter:
https://www.deltapvi.com.au/assets/Uploads/Delta-H5A-222-brochure-v2.2-web-compressed-2.pdf
And here’s specs on the Goodwe GW5048D-ES:
https://www.goodwe.com.au/Public/Uploads/productsau/pdf/ES.pdf
The Goodwe is made for use with a battery while the Delta is a standard grid-tie inverter.
I have been advised that the Goodwe GW5048D-ES can be installed and operated without a battery system being connected (which then would allow for monitoring load, generation, and exporting, simultaneously, if my understanding is correct).
Thus, it is my understanding, that both inverters have the ability to operate, with either batteries connected, or, no batteries connected.
Thus, my understanding is that both inverters can be run with either batteries connected, or, no batteries connected, and, as the Goodwe GW5048D-ES apparently allows the PV panels to keep generating electricity, and, converting the electricity from the panels, for use by the household and battery charging, when grid supply failures occur, when batteries are connected, I expect that it can also do this, when no batteries are connected, unless I am otherwise informed.
Sorry, I gave you the wrong Delta inverter link. Here’s the right one:
https://www.deltapvi.com.au/assets/bulkUpload/E5-Brochure.pdf
I’m afraid all I know about it is what I’ve read in that brochure. There are a limited number of inverters that say they can provide power to the home during a blackout without a battery by using power from the solar system. While this sounds good, in practice it’s difficult to manage as a cloud can easily drop output and cause the system to trip and even with clear skies solar generation will be low early and late in the day. On the bright side, it doesn’t take a lot of power to run a fridge and freezer and charge laptops. All else equal I’d rather have that function than not have it.
The Hybrid Delta H5E_220 also has an identical standalone feature in the E5
https://support.delta-es.com.au/wp-content/uploads/2022/06/Installation-Manual-20220518-H5E_220.pdf
I have a mountain of burnt out or otherwise malfunctioning electronic equipment related to solar. All of the inverters, solar controllers and batteries I have attempted to go off grid with turned out to be junk. You would think that 20 years into the 21st century one should easily be able to utilize solar panels, batteries and an inverter to provide continuous power. And to hear that many hybrid inverters will also leave you in the dark during a blackout is disappointing. Working with solar always seems to be about workarounds.
Sorry to hear of the issues with burnt out gear. Our off grid main system here is 12 Kw solar, 48 volt submarine battery band, 5 Kva inverter/charger, 2 PL 60 regulators, a Victron 150/100 regulator, 12 kva diesel generator associated metering etc. It runs 2 houses, including air con, and electric boosts the solar hot waters as required. The sine wave power is actually better than the grid.
I also have a homemade 3 phase converter that runs the fire wood saw bench from the main system. Yes, its cost, but it just works. $25 K for battery’s alone.
Th genset only runs when I need to weld or occasionally after a week of wet weather and we are no lazy to run the wood heater and need to boost the hot water.
Hi,
I am interested in this hybrid option as an interim before adding batteries later down the road. I found the Fronius Symo Gen 24 (3 phase hybrid inverter) which offers something they call PV Point which provides 3kw of power to a new single socket that becomes energised during an outage.
The installer I have been speaking to about it tells me that it can also work in the way mentioned above unsing an auto-transfer switch. I have 3 phase power and the installer tells me that this inverter can provide up to 3Kw per phase in this mode (assuming you have enough PV power available).
My question is does this sound right and does anyone have any experience with this kind of install. It sounds like a great half way ground while waiting to add batteries in the future.
The system I am looking to add would be around 12-13Kw with the 10kw Fronius symo gen 24 hybrid inverter.
Thanks for any help
Is there an external blackout device that can be installed in a solar + battery system? If yes how much is it likely to cost me?
Hi Seth
If you get a battery with backup power capability, then you will be able to disconnect from the grid and operate entirely from the battery.
The solar company I’m working with said this inverter was not compliant with Australian Standards (end of May 2022). Does this mean there is nothing like this out there that is compliant?
It seems that the new Sungrow hybrid inverter can supply power to the house without a battery when sufficient solar is available. https://www.acsolarwarehouse.com/news/new-sungrow-hybrid-inverters-can-operate-without-the-grid-or-a-battery/
What if your Inverter is set to zero export? Can’t you just turn off anti islanding in this case?
Hi Alain,
AS4777 mandates what solar inverters can and cant do, including a lot of requirements around power quality but most importantly around islanding. When the inverter effectively measures the impedance back to the street transformer as part of it’s operation it’s not as simple as “just turning it off”
There are inverters that offer backup without batteries, but it’s the batteries that give you a buffer and offer proper stability.
But how do you isolate power from going back into the power grid with out turning the main switch off Eg what product do you use
I had been in the UPS industry for 20 years and retired a few years ago. I have been looking at options to utilize my 8kw solar system during a power outage. It is not a simple process unless you spend a lot of money.
The first problem is to get the solar inverter running without trying to power all of Australia. The solar inverter needs to synchronize to a power or mains source.
The other problem is how the inverter handles the power it generates. I am unsure of solar inverter technology as to whether it will supply full generated power at all times or whether it will regulate the output to suit the load.
A battery is the obvious addition as that can generate an AC sync voltage and will store power when the solar is unavailable. The drawback is that the battery inverter must be isolated from the house/mains power so it is also not trying to power the grid when the mains fail. But it can be used as a stand alone system of power.
The issue here is one of cost depending on how much of this power you need and size of battery. If cost in not an issue then go and buy a large UPS complete with battery but a typical battery is usually sized for about 10 – 20 minutes of rated power,
I do not think there is a simple one box solution that will achieve utilizing solar power in a cost effective manner during an extended power outage.
I should add that I am looking for a solution after the GC storm last year that left me without power for nearly 5 days. So i just want a short term emergency power source without an excessive cost.
Any suggestions welcomed.
Hi Trevor,
I suspect a bloke with your experience might like the concept of a Fronius Gen24 with “pv point” to offer battery-less backup. Have a look at this article and let me know if you think plugging in a 3000VA UPS downstream of the pv point outlet would be a good way to make it a stiffer supply that doesn’t brown out if there are clouds coming and going?
Have you had any experience with the range of “camping generator” style battery units?
We got a 10 kWh ESS battery and inverter for $10k and for an extra $500 it was wired as an UPS, it is seamless to the point that if the power goes out we simply don’t notice unless you look at the app on the iPad; it makes us almost standalone.
FWIIW I have lived in NQ and always had an at least 2kw generator that was invariably used in cyclone season fridge, lights and fans a decent Honda about $1500 and again some electrical work.
Is there any other inverter currently available that has a similar Stand Alone option with out installing batteries?
Hi Andy,
There’s one I’d recommend:
https://www.solarquotes.com.au/blog/fronius-primo-gen24-mb1928/
but you might want to combine it with a 3kW UPS system. If you can find one for cheap it would be a bit more capable
Others are a bit gun shy about offering it.
https://www.solarquotes.com.au/blog/enphase-sunlight-backup/