Blackouts, Solar Power And Batteries

Solar power and battery systems during blackouts

Whenever there are significant blackout events, there’s an uptick in solar power and battery interest.

Hailstorms, heavy rain, lightning and wild winds have recently pummeled various parts of the country again; leaving left hundreds of thousands of households and businesses without mains grid electricity – and some for extended periods.

Many solar owners would have been without power too during these blackouts. The reason is safety related.

Inverters – Anti-Islanding

Conventional solar inverters have a required feature called “anti-islanding“, which detects the loss of grid power and automatically switches off the inverter. This is to protect workers attempting to restore power. If electricity is continuing to be exported to the grid while fixes are being carried out, this poses an electrocution threat to those working on infrastructure. It also threatens creating further damage to infrastructure.

But as solar tech gets smarter, there will be more options for having backup power from solar during a blackout – without a battery. “Grid forming” inverters have the ability to safely isolate a system from the mains grid during a blackout and enable solar panels to continue supplying power to the home. One such product is the Enphase IQ8 microinverter, which is expected to be available in Australia in the first half of next year.

That’s great for having some electricity available during the day, but under particularly unfavourable daytime conditions for solar energy generation and at night, a battery (or generator) is required – and not all batteries are equal when it comes to backup power during a blackout.

Solar Batteries And Blackouts

Having solar battery storage installed doesn’t necessarily mean you’ll have backup power in the event of a blackout, or an extended event.

Many battery systems currently available in Australia either have backup as an optional extra or don’t provide this capability at all. On the SolarQuotes solar battery comparison table, look along the “off-grid capable” row to see models that can provide backup power during a blackout event.

Additionally, most batteries will not back up your whole house under normal usage while the grid is down. This is because the power demands of multiple energy-hungry appliances used at the same time would overload the battery.

For example, a Tesla Powerwall has a 7kW peak / 5kW continuous power output rating. Using a conventional oven, the kettle and dishwasher at the same time is beyond its capabilities and the Powerwall would shut down.

But it’s not just about power; the energy (there’s a difference) requirements of some appliances would see a battery drained very quickly.

This is why when installing a battery a decision will need to be made as to which electrical circuits will be backed up – usually just critical loads such as the refrigerator, lighting and power for small appliances.

Also, depending on the system, it might not be able to use your rooftop solar panels to charge the battery during a blackout. So, whatever you have in your battery may be all you have until mains electricity is restored.

If having backup power in the event of a blackout is important to you, ensure you make this requirement very clear when choosing a solar battery. If you’re looking for installers who really know their home energy storage stuff – SolarQuotes can help.

About Michael Bloch

Michael caught the solar power bug after purchasing components to cobble together a small off-grid PV system in 2008. He's been reporting on Australian and international solar energy news ever since.


  1. George Kaplan says

    Is it still very expensive to apocalypse proof a triple phase house as was the case in 2018?


    While I don’t expect it’ll happen for about a decade given current prices, I suspect in the long term I’ll be looking for either an off-grid compatible battery system, or be fully off-grid, with the decision based on just how badly usage and supply charges have risen. In the last couple of years supply charges have risen 20%. Usage charges appear stable – though it’s hard to compare cross-plan over time, and of course FiTs are dropping fast – roughly 30% in less than a year. As costs rise and solar revenue plunges the purchase electricity versus pay off a battery equation changes.

    • Not sure about supply charges rising 20%??

      For Endeavour Energy area that I’m in, historical prices are: (for ToU)

      2014-15 56.34c/day
      2015-16 49.72c/day
      2016-17 50.41c/day
      2017-18 55.33c/day
      2018-19 39c/day
      2019-20 40.47c/day
      2020-21 41.59c/day

      These prices can be found on the AER’s website.

      It appears, Endeavour reduced its ToU daily supply charge by 26% from its 2014-2015 price over 7 years.

      Of course, what the retail market does with the daily supply charge is a whole new ball game. So, it appears my distributor is being fair, it’s the retail market that would have to share the responsibility of jacking the daily supply charges.

      All this rambling on about the distributor increasing prices is really unwarranted when these prices are revealed.

      FiT is directly tied to wholesale prices, the distributor can’t do a thing about that since, well, it’s a distributor, not a generator or retailer The retailer will determine what it will pay for FiT since it’s substituted for the price the retailer would have paid to the big generators for their NEM wholesale price. Only the retailer’s bean counter can work out what the retailer is prepared to pay for FiT when they work out its operating costs and purchasing power from the NEM.

      I find that usage charges vary by a wide margin even with 60 retailers in the same distribution network in my area. Usage charges are extremely unstable, they change every month when looking at plans.

      The cheapest off peak ToU I found is 11c/kWh (not to be confused with controlled load) and is this offered in the daytime (not just night time). The dearest peak rate I found is 39.5c/kWh. With everybody else in between. How is that 60 different retailers can offer such different rates, when the source of electrons is coming from the same place. My local street transformer is connected to the local zone substation (no generators nearby). The local zone substation is connected to the nearest district substation (no generators nearby). The local district substation would be connected to the transmission switchyard not far away (still no generators nearby). The nearest generator is about 100km as the crow flies from where I am. Even then, I don’t know if it’s that generator supplying my electrons, depends on how the network switching takes place where demand is and where supply can fit in. You can’t force one electron from the cheapest generator to your house to get cheap electricity on the grid. (except when it comes directly off one’s PV system). If there was some magical way to mark electrons that it’s cheaper, that would alter the market quite a bit, shame it can’t be done….. everyone would be wanting electrons marked as being coming from a solar or wind farm! Dirty electrons from coal would be avoided as much as possible, I wonder if those coal loving advocates would be happy to buy the dirty electrons at a higher price just for the sake of holding up their dearly beloved tenets of keeping the FF industry alive.

      The retail market is clearly to blame for the prices we pay for electricity. Get rid of the retail market and bring back the distributors incorporating direct sales to consumers as it was once.

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