DRIVING OUR ENERGY FUTURE SERIES: Solar Citizens’ clean energy campaigner Philippa England explains how to set up a home battery to help withstand power outage from her own experience.
Earlier this year Southeast Queensland received another wake up call to climate change, when ex-tropical Cyclone Alfred made landfall on the Moreton Bay Islands, directly off the coast from Brisbane on 7 March.
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Although it was downgraded from a category 4 to a category 1-2 by the time it “landed”, the ex-cyclone caused “damaging wind gusts, heavy rainfall with subsequent flooding impacts and severe coastal erosion of beaches”.
The trail of destruction left more than half a million households without power over southeast Queensland and northeastern New South Wales. Many remained without power for days.
But like me, people who had a home battery with off-grid capability, were black-out free. When the cyclone arrived, my home solar and Sigenstor battery kept working throughout a modest 16 hour power cut. In fact, when the grid power supply did come back on, our battery was still full!
By turning off the pool pump we had reduced our energy use and generated enough power from our solar panels to keep the battery topped up – throughout the night and during a cloudy day.
A neighbour down the road was also thankful for his home battery during this extended storm. Dr David Reiter told us: “thanks to our two solar arrays and battery, we never lost power to our essential appliances or to my two life support devices – a CPAP (continuous positive airway pressure) sleep machine and pacemaker monitor. I was told by my power provider that they couldn’t guarantee emergency power to us from the grid from their supposed ‘Emergency Support Program’.”
Not everyone was so lucky – other friends ran down their battery storage and were dismayed to find it didn’t replenish itself once depleted. They had a battery they thought was black-out proof, but once the battery was fully depleted, the inverter switched off – and without the inverter going, their solar panels stopped generating power to refill the battery.
Blackout protection VS full off-grid capability
So, what’s the difference between short term blackout protection and full off-grid capability?
Batteries can serve multiple functions:
- storage – primary purpose of storing energy generated by your solar panels
- firming – using your stored energy to continue your independent energy supply throughout the day when your solar production is less than your actual usage
- blackout protection – for when there’s a short term interruption to your grid supply (for minutes or a couple of hours)
- full off grid capability – your inverter will stay on, allowing your solar to keep generating and your battery to keep storing for however long it takes for grid power (if you connect to the grid) to come back on.
If the battery you are interested in states it can give you “uninterruptible power supply” (UPS), “back-up power” or “blackout protection”, it may not actually give you full off grid capability – so check with your installer. Like my unlucky neighbour, these batteries may not keep your inverter working so your solar won’t be able to refill the battery once you have drained it.
If you want full off grid capability, then look out for options such as “standalone”, “islandable”, or “offgrid capable” batteries and check you will be getting all the equipment to make sure your installation will be able to function off grid. For instance, I paid $2,000 for a separate Energy Gateway with my Sigenstor battery to be guaranteed off-grid capability. Always check with your installer.
As Finn Peacock from Solar Quotes advises, if they tell you your system will be off grid capable be sure to “get it in writing”.
With the right choice of inverter and/or gateway, household storage systems made by Sungrow, Sigenergy and BYD can all be set up to function fully off grid. Tesla Powerwall 3 batteries however are designed to be grid connected and can no longer be installed in off grid systems.
Further reading:
Solar Citizens – Home Battery FAQ
Australian Government – Get to know solar technology and Batteries | energy.gov.au
Solar Quotes The Do’s and Don’ts of buying batteries