The Solar Guide Australia has no affiliation with Flow Power or any other electricity providers. This is an independent review.
If you have a home battery, choosing the right electricity plan is becoming almost as important as choosing the battery itself.
Australia now has so much rooftop solar that electricity can be cheap and plentiful during the middle of the day. But in the evening, solar generation falls away just as household electricity demand increases.
That is creating a new type of battery energy plan that rewards households for exporting stored electricity when the grid values it most.
The Flow Power battery export plan is a good example. Instead of paying the same solar feed-in tariff throughout the day, it offers a much higher rate for battery exports during a four-hour evening window.
The big change in battery energy plans is simple: it’s becoming less about how much electricity you export and more about when you export it.
Why battery energy plans are changing
Traditional electricity plans are fairly straightforward. You buy electricity at a set rate and receive a feed-in tariff for excess solar sent to the grid.
Newer electricity retailers are taking a different approach.
Electricity prices in the wholesale energy market change throughout the day depending on supply and demand. While some retailers expose customers more directly to wholesale energy prices, others use time-based rates and incentives to encourage customers to use or export electricity at particular times.
For households with batteries, that creates new opportunities.
We’ve covered these different approaches in our guide to Amber vs OVO vs GloBird, including how newer electricity plans compare with the traditional retailer model.
Flow Power’s offer is another example of this changing market.
Why evening battery exports are worth more
Australia has millions of rooftop solar systems producing electricity at roughly the same time.
In the middle of a sunny day, there can be plenty of solar electricity available. This has reduced the value of daytime exports and is one reason traditional solar feed-in tariffs have fallen.
The evening is different.
Solar generation disappears while households are cooking dinner, heating and cooling their homes and using appliances. Electricity can become more valuable during these periods.
A home battery lets you store solar electricity during the day and decide whether to use or export it later.
A solar system produces electricity when the sun is shining. A battery gives you control over when that electricity is used, and increasingly, when it is sold.
That’s why we expect battery export plans and other time-based electricity offers to become more common as Australian battery ownership grows.
How does the Flow Power battery plan work?
Under the Flow Power rates supplied for this article, eligible customers in South Australia, New South Wales and South East Queensland receive 35c/kWh for the first 15kWh exported between 5:30pm and 9:30pm.
In Victoria, the listed rate is 30c/kWh for the first 15kWh.
After the first 15kWh, the export rate drops to 10c/kWh. The offer details supplied for this article also state that exports outside the 5:30pm to 9:30pm window don’t receive an export payment under this particular offer.
For customers receiving 35c/kWh, exporting the full 15kWh is worth:
15kWh × $0.35 = $5.25 per day
That doesn’t mean every battery owner will earn $5.25 every day. Your battery needs enough stored energy, and your inverter needs enough spare capacity after supplying the house.
But it gives us a useful number for assessing whether the Flow Power plan suits your system.
Why Flow Power’s 4 hour export window matters
One of the most important parts of the Flow Power offer isn’t actually the 35c/kWh rate.
It’s the four-hour window.
Flow Power previously used a shorter two-hour period with a higher 45c/kWh export rate. That favoured batteries with larger inverters because you needed to move a lot of electricity quickly.
The longer window changes the equation.
To export 15kWh across four hours requires an average of:
15kWh ÷ 4 hours = 3.75kW
Imagine you have a 5kW battery inverter and your home is consuming around 1.25kW.
That leaves approximately 3.75kW available for export. Maintain that across four hours and you reach 15kWh.
You don’t necessarily need a huge battery inverter to make the Flow Power plan worthwhile. The four-hour window means many standard residential systems can potentially reach the valuable 15kWh export target.
That’s one of the biggest differences between this plan and export offers that reward households for pushing large amounts of electricity into the grid over a short period.
Does a bigger battery earn much more?
Yes, but there’s an important catch.
Once you’ve exported the first 15kWh, the rate drops substantially.
At 35c/kWh, the first 15kWh earns $5.25.
Using the rates supplied for this article, a much larger system exporting 48kWh during the same window would earn $8.55 because the additional 33kWh earns only 10c/kWh.
So a bigger battery can earn more, but the returns diminish once you pass 15kWh.
For this Flow Power offer, comfortably reaching the first 15kWh of evening exports matters more than simply installing the biggest battery and inverter possible.
That distinction is important if you’re currently sizing a battery.
We wouldn’t recommend spending thousands of dollars more on battery capacity purely to chase one retailer’s current export tariff. Electricity plans and rates can change.
Your battery should first make sense for your household’s electricity usage, solar production, backup requirements and future needs. A good battery energy plan can then improve the economics.
Who is the Flow Power battery plan best suited to?
The Flow Power plan is most interesting for households that already have a battery, or are planning to install one, and expect to have spare stored energy available in the evening.
The ideal household will generally have enough daytime solar to charge the battery, enough battery capacity to cover its own needs while leaving some energy available to export, and sufficient inverter capacity to export close to 15kWh during the four-hour window.
You don’t necessarily need an oversized inverter.
That’s what makes this offer particularly interesting. A fairly normal residential battery system may be able to capture much of the benefit.
Households with modular batteries may also want to consider future expansion when sizing their system, particularly if battery export plans continue to become more common.
Who might not suit the Flow Power plan?
A high battery feed-in tariff doesn’t automatically make an electricity plan good value.
If your household uses most of its stored energy during the evening, there may be little left to export.
High evening loads can also reduce how much inverter capacity is available to send electricity back to the grid.
Most importantly, you need to consider the whole electricity plan, not just the headline export rate. Usage rates, daily supply charges and other conditions can all affect the final result.
The best battery energy plan isn’t necessarily the one with the highest feed-in tariff. It’s the plan that produces the lowest overall electricity cost for the way your household actually uses its battery.
That’s a useful rule when comparing Flow Power with other battery electricity plans.
Flow Power vs wholesale energy plans
Flow Power’s offer also highlights an important distinction between different types of modern electricity plans.
A wholesale energy plan can expose customers more directly to movements in wholesale electricity prices. That can create opportunities when market prices are high, but the value available can also change considerably.
Flow Power’s evening export offer is easier to understand because the valuable export period and rate are defined in advance under the offer described here.
Neither approach is automatically better.
A household that wants predictable rules may prefer a fixed time-based battery export plan. Someone comfortable actively managing their battery and accepting more price variability may find a wholesale energy model more appealing.
The right choice depends on how involved you want to be and how your battery is configured.
Is Flow Power one of the best battery energy plans?
For the right household, Flow Power is certainly the type of plan worth comparing when looking for the best battery energy plans in Australia.
The combination of a four-hour evening window and a higher rate for the first 15kWh makes it particularly relevant to households that can regularly have spare battery capacity available after sunset.
But there is no single “best battery electricity plan” for every home.
A household with a small battery, high evening consumption and limited exports has very different requirements from a household with a large solar array and plenty of stored energy available each night.
When comparing battery energy plans, look at the complete picture: import rates, supply charges, export rates, export windows, limits and how much energy your battery can realistically make available.
The bigger trend for Australian battery owners
Flow Power’s offer is interesting, but the bigger story is where Australia’s electricity market is heading.
Home batteries aren’t only becoming a way to store your solar for later.
They’re becoming a flexible energy asset.
As battery ownership grows, we expect more electricity retailers to introduce plans that encourage customers to charge when electricity is plentiful and export when the grid needs it.
That could improve the return on investment of a home battery, particularly for households with enough capacity to cover their own electricity needs and still participate in these higher-value export periods.
The future value of a home battery won’t just depend on how much energy it can store. It will increasingly depend on how intelligently that energy can be bought, stored, used and exported.
The bottom line
Flow Power’s battery export offer shows why the electricity plan you choose is becoming an increasingly important part of owning a home battery.
The headline 35c/kWh export rate is attractive, but the 15kWh target and four-hour evening window are arguably more important.
You don’t necessarily need a huge inverter or battery to benefit. For many households, the sweet spot will be having enough capacity to comfortably cover their own electricity needs while leaving some energy available for higher-value evening exports.
And as more retailers introduce battery-specific, time-based and wholesale energy plans, choosing the right electricity plan could become an important part of improving your battery’s overall return.
Looking for the right solar and battery system?
The best battery energy plan can only do so much if the system itself isn’t properly sized for your home.
Your solar production, household consumption, battery capacity and inverter size all need to work together.
Solar Guide Australia helps homeowners find trusted local solar and battery installers who can assess your electricity usage and recommend a system suited to how you actually use power.
Use Solar Guide Australia to compare trusted local installers and find a solar and battery system that makes sense for your home today, while giving you flexibility as battery electricity plans continue to evolve.
Electricity rates, eligibility and plan conditions can change. Figures in this article are based on the Flow Power offer details supplied at the time of writing. Always confirm current rates and conditions for your address before choosing an electricity plan or purchasing additional battery capacity.
