Automating around Australian electricity tariffs
Low feed-in tariffs, time-of-use pricing and free midday windows change what a good energy automation looks like.
For years the goal with rooftop solar was to export as much as possible. With feed-in tariffs now often worth a few cents per kilowatt-hour, the better question is usually how to use your own solar at home, and when to draw from the grid.
Read your tariff first
The right automation depends entirely on the plan you are on. Before automating anything, write down:
- Peak, shoulder and off-peak times and prices
- Your feed-in tariff, and whether it changes by time of day
- Any free or very cheap window some retailers now offer in the middle of the day
- Daily supply charges and any demand charge
Retailers change plans regularly, so keep the times in adjustable settings rather than hard-coding them.
Move flexible loads, not everything
Good candidates are loads that can wait a few hours without anyone noticing: hot water, the dishwasher, the washing machine, pool pumps and electric car charging. Poor candidates are anything that affects comfort or safety when it runs late.
In the BK Home Automations showcase, both heat-pump hot water units switch to a faster heating mode during a free midday window, and the dishwasher and washer start at the beginning of it. The appliances only start if they have been loaded, their doors are closed and they are not already running.
Solar surplus charging
Charging an EV from spare solar sounds simple, but clouds move quickly. Good designs step the charging current gradually, wait for readings to settle, and have a hard stop if the house starts importing from the grid when it shouldn’t. A home battery floor matters too: the car should not drain the battery the house needs overnight.
Home batteries
A battery’s default mode is usually sensible. Automation earns its place when a tariff makes timing matter, for example charging during a free window or holding charge for an evening peak. Anything that forces charging or discharging should have clear start and stop conditions and a plan for what happens after a restart.
Measure the result
Split grid import into the windows your tariff uses, so you can see what the automations actually changed. Compare like-for-like weeks before claiming savings; weather and household routines move the numbers more than most automations do.
General information only. Tariffs, retailer offers and network rules differ by state and change over time; check your own plan and bill.