Real household energy analysis
Which electricity retailer is best for solar and battery owners?
We used a full year of real household data to compare Amber Electric with 25 retail electricity plans. Then tested how dramatically the result changes when two Tesla Powerwalls are either left in basic Self-Powered mode or deliberately controlled around the tariff.
The best battery plan can become one of the worst if the battery is not controlled properly
Electricity comparison sites usually ask how many kilowatt-hours a household imports. That is useful for a home without storage, but it misses the most important variable for a battery owner: when the battery charges, when it discharges and whether it exports deliberately.
In basic Self-Powered mode, the Powerwalls charged only from surplus solar and discharged whenever household demand exceeded solar production. There was no grid charging, no tariff schedule and no planned export. Under that setup, the cheapest alternative was Nectr Power Perks at approximately $1,456—about $401 more than Amber’s ongoing cost.
Once the same batteries were allowed to charge during cheap or free windows, retain energy for expensive periods and export during permitted premium feed-in windows, the ranking changed completely.
For example, AGL Battery Rewards moved from approximately $1,698 in basic mode to $518 with tariff-aware operation. Flow Power 4Free moved from about $2,309 to $863. Red Energy Solar Sharer moved from approximately $1,784 to $605.
Those differences do not come from changing the solar panels or installing more battery capacity. They come from matching the existing battery to the tariff.
How we compared Amber with 25 alternative electricity plans
The analysis used the physical energy profile from 1 August 2025 to 31 July 2026. Current advertised August 2026 retail rates were then applied to that same 12-month profile so every plan faced an identical household.
The home and energy system
The home has solar and two Tesla Powerwall 2 batteries with 27kWh of combined nominal storage. A 20% backup reserve was maintained, leaving 21.6kWh for everyday use. Charging, discharging and site export were limited to 10kW.
The energy data
We used the full Tesla dataset for load, solar, battery and grid behaviour, plus three months of Amber interval data. The Tesla profile was calibrated so annual imports and exports reconciled with the revenue-meter totals in the bills.
Realistic battery losses
The model used the observed whole-system round-trip efficiency of approximately 82.16%, including conversion and standby losses. Buying 1kWh cheaply therefore did not create 1kWh available to sell later.
What was excluded
Sign-up bonuses, rewards points, Netflix value and temporary promotions were excluded. Battery degradation was also excluded because this comparison focuses on the retail bill, not complete battery lifetime economics.
Detailed modelling assumptions
- The Powerwall reserve never fell below 20%.
- Grid charging was allowed where the plan and system supported it.
- Grid-charged energy could be exported later where that behaviour was confirmed as permitted and financially useful.
- The model did not allow an impossible simultaneous import and export in the same interval. Energy had to be charged, stored, incur efficiency losses and then be exported later.
- A short Tesla data fault, when the batteries were stuck at 98%, was filled using a reasonable profile based on surrounding periods.
- Rates were applied as supplied in the plan documents and screenshots. Plan eligibility and availability still need to be checked at the customer’s address.
Why the Amber comparison uses $1,055 rather than $615
Amber’s ongoing charges after feed-in credits totalled approximately $1,055: about $1,325 in charges less roughly $270 in export credits. The actual out-of-pocket result was closer to $615, but that included $440 in non-tariff credits—$350 in referral rewards, a $75 government rebate and a $15 battery-partner referral discount.
Those credits were real, but they are not a dependable ongoing feature of the tariff. We therefore used $1,055 as the fair comparison point and show $615 separately as the actual result after those credits.
Interactive results: see what battery control changes
The charts below use the same annual household profile. Switch between basic and tariff-aware operation, or choose a plan to see the three different cost views.
Lowest annual bills under each battery strategy
Explore a specific retailer plan
Which plans performed best with tariff-aware battery control?
1. AGL Battery Rewards Plan: $518
This was the lowest modelled cost, approximately $537 below Amber’s ongoing result. The strategy charged from solar and cheap off-peak electricity, retained energy and deliberately exported between 5pm and 9pm at 27c/kWh. Annual supply was about $617, usage charges were $1,076 and feed-in credits reached approximately $1,175.
That result is conditional. Access to the plan, export rate and control method may depend on battery, retailer or virtual power plant eligibility. It should not be treated as available to every Australian Powerwall owner.
2. Red Energy Solar Sharer: $605
The model used the plan’s free 11am-to-2pm allowance to fill the battery, cover later household consumption and export remaining surplus at 5c/kWh. The estimated bill was $649 supply plus $223 usage, less $268 in feed-in credits.
3. OVO The Basic Free 4: $708
The main opportunity was four hours of free electricity from 11am to 3pm. The battery filled during that window and discharged later to avoid paid peak and shoulder imports. The feed-in rate was only 1c/kWh, so load shifting—not export revenue—created most of the value.
4. Origin Standing Solar Sharer: $712
This used a similar approach: fill the battery from the free 11am-to-2pm allowance, use that energy later and export surplus at 3c/kWh. It finished approximately $343 below Amber in this case study.
5. Flow Power 4Free: $863
The plan had a high annual supply charge of about $845, but tariff-aware control used the 11am-to-3pm free window and retained energy for the 5:30pm-to-9:30pm premium export period. That reduced the modelled bill from $2,309 in basic mode to approximately $863.
The high feed-in-tariff trap
A high feed-in tariff does not automatically create the cheapest plan. Flow Power Happy Hour offered up to 35c/kWh during its evening window, yet its standard usage and supply charges produced an optimised result of approximately $2,153—more than double Amber’s ongoing cost.
A useful comparison must consider the complete tariff: daily supply, import prices, time windows, export caps, battery capacity, power limits and efficiency losses. The headline feed-in rate is only one piece.
Complete electricity retailer comparison tables
All amounts are annual and rounded to the nearest dollar. “Recorded battery” prices the household’s observed battery behaviour on each alternative tariff. “Basic” uses ordinary Self-Powered operation. “Tariff-aware” deliberately optimises charging, discharging and permitted export around the plan.
Table 1: Tariff-aware battery control, including permitted grid-charged export
| Rank | Plan | Recorded battery | Tariff-aware cost | Vs Amber | Control saving | Required battery operation | Annual charge breakdown |
|---|---|---|---|---|---|---|---|
| Ref. | Amber – ongoing core cost | $1,055 | $1,055 | $0 | — | Actual Amber-controlled operation; not independently re-optimised. | $1,325 charges − $270 FiT = $1,055 |
| 1 | AGL – Battery Rewards Plan | $1,120 | $518 | $537 cheaper | $602 | Charge from solar/11am–4pm off-peak; reserve energy and force-export 5–9pm at 27c/kWh. | $617 supply + $1,076 usage − $1,175 FiT = $518 |
| 2 | Red Energy – Solar Sharer Offer | $1,225 | $605 | $451 cheaper | $620 | Fill from the 11am–2pm free allowance; serve later load, then export surplus at 5c/kWh. | $649 supply + $223 usage − $268 FiT = $605 |
| 3 | OVO – The Basic Free 4 | $1,218 | $708 | $347 cheaper | $510 | Fill 11am–3pm free; discharge outside the free window; export only surplus at 1c/kWh. | $579 supply + $201 usage − $72 FiT = $708 |
| 4 | Origin – Standing Solar Sharer | $1,276 | $712 | $343 cheaper | $564 | Fill from the 11am–2pm free allowance; serve later load, then export surplus at 3c/kWh. | $649 supply + $224 usage − $161 FiT = $712 |
| 5 | Flow Power – 4Free | $1,730 | $863 | $193 cheaper | $867 | Use the 11am–3pm free allowance; reserve energy for 5:30–9:30pm load/export at up to 20c/kWh. | $845 supply + $345 usage − $328 FiT = $863 |
| 6 | Energy Locals – Solar Sharer Offer | $1,353 | $876 | $179 cheaper | $477 | Fill from the 11am–2pm free allowance; discharge outside it; never deliberately export at 0c. | $649 supply + $227 usage − $0 FiT = $876 |
| 7 | OVO – The Basic | $1,335 | $968 | $87 cheaper | $367 | Grid-charge 11am–4pm off-peak; discharge through 4–9pm peak and dear shoulder periods. | $538 supply + $462 usage − $33 FiT = $968 |
| 8 | Powershop – Switch Saver | $1,373 | $975 | $80 cheaper | $398 | Grid-charge 11am–4pm off-peak; discharge through 4–9pm peak and dear shoulder periods. | $503 supply + $489 usage − $16 FiT = $975 |
| 9 | Origin – Solar Boost Variable | $1,340 | $1,002 | $53 cheaper | $338 | Prioritise the first 8kWh/day of solar export at 8c; off-peak charge for 4–9pm peak load. | $649 supply + $581 usage − $228 FiT = $1,002 |
| 10 | Origin – Go Variable Ongoing | $1,346 | $1,011 | $45 cheaper | $336 | Grid-charge 11am–4pm off-peak; discharge 4–9pm peak, then shoulder where worthwhile. | $623 supply + $436 usage − $49 FiT = $1,011 |
| 11 | AGL – Solar Savers | $1,352 | $1,012 | $43 cheaper | $340 | Prioritise the first 8kWh/day of solar export at 8c; off-peak charge for 4–9pm peak load. | $649 supply + $581 usage − $218 FiT = $1,012 |
| 12 | AGL – Smart Saver | $1,357 | $1,016 | $39 cheaper | $341 | Grid-charge 11am–4pm off-peak; discharge 4–9pm peak, then shoulder where worthwhile. | $617 supply + $432 usage − $33 FiT = $1,016 |
| 13 | AGL – Netflix Plan | $1,374 | $1,033 | $22 cheaper | $341 | Grid-charge 11am–4pm off-peak; discharge 4–9pm peak, then shoulder where worthwhile. | $634 supply + $432 usage − $33 FiT = $1,033 |
| 14 | Origin – Everyday Rewards Variable | $1,405 | $1,055 | Effectively tied | $351 | Grid-charge 11am–4pm off-peak; discharge 4–9pm peak, then shoulder where worthwhile. | $649 supply + $454 usage − $49 FiT = $1,055 |
| 15 | Nectr – Power Perks TOU | $1,425 | $1,178 | $123 dearer | $247 | Charge 11am–4pm off-peak/solar; discharge 4–9pm peak where the price spread pays. | $512 supply + $699 usage − $33 FiT = $1,178 |
| 16 | Alinta – HomeDeal Smart | $1,912 | $1,563 | $508 dearer | $349 | Self-Powered solar charging; no grid arbitrage or deliberate export on the flat tariff. | $617 supply + $979 usage − $33 FiT = $1,563 |
| 17 | Alinta – SolarBalance Ready | $2,008 | $1,677 | $621 dearer | $332 | Prioritise up to 8kWh/day export at 10c; solar-charge remaining surplus; no grid arbitrage. | $680 supply + $1,079 usage − $83 FiT = $1,677 |
| 18 | Red Energy – Living Energy Saver | $2,090 | $1,686 | $631 dearer | $403 | Self-Powered solar charging; no grid arbitrage or deliberate export. | $602 supply + $1,100 usage − $16 FiT = $1,686 |
| 19 | Red Energy – Qantas Red Saver | $2,090 | $1,686 | $631 dearer | $403 | Self-Powered solar charging; no grid arbitrage or deliberate export. | $602 supply + $1,100 usage − $16 FiT = $1,686 |
| 20 | Red Energy – Living Energy Solar Saver | $2,103 | $1,732 | $677 dearer | $371 | Self-Powered solar charging; serve load before exporting at 5c/kWh. | $701 supply + $1,113 usage − $81 FiT = $1,732 |
| 21 | Red Energy – Qantas Red Solar Saver | $2,103 | $1,732 | $677 dearer | $371 | Self-Powered solar charging; serve load before exporting at 5c/kWh. | $701 supply + $1,113 usage − $81 FiT = $1,732 |
| 22 | Red Energy – Red BCNA Saver | $2,103 | $1,732 | $677 dearer | $371 | Self-Powered solar charging; serve load before exporting at 5c/kWh. | $701 supply + $1,113 usage − $81 FiT = $1,732 |
| 23 | Red Energy – Red Wildlife Saver | $2,103 | $1,732 | $677 dearer | $371 | Self-Powered solar charging; serve load before exporting at 5c/kWh. | $701 supply + $1,113 usage − $81 FiT = $1,732 |
| 24 | Alinta – Standing Offer | $2,180 | $1,781 | $726 dearer | $399 | Self-Powered solar charging; no grid arbitrage or deliberate export. | $701 supply + $1,113 usage − $33 FiT = $1,781 |
| 25 | Flow Power – Happy Hour | $2,757 | $2,153 | $1,098 dearer | $603 | Solar-charge only; cover load first, then force-export 5:30–9:30pm at up to 35c/kWh. | $845 supply + $1,610 usage − $302 FiT = $2,153 |
“Control saving” is the difference between pricing the recorded battery behaviour and the tariff-aware model. Some forced-export strategies may require retailer/VPP integration or a compatible external energy-management system rather than only the standard Tesla app.
Table 2: Basic Self-Powered operation with no time-based control
| Rank | Plan | Recorded battery | Basic Self-Powered | Vs Amber | Basic vs recorded | Required battery operation | Annual charge breakdown |
|---|---|---|---|---|---|---|---|
| Ref. | Amber – ongoing core cost | $1,055 | $1,055 | $0 | — | Actual Amber operation used as the reference. | $1,325 charges − $270 FiT = $1,055 |
| 1 | Nectr – Power Perks TOU | $1,425 | $1,456 | $401 dearer | $31 dearer | Self-Powered; 20% reserve; no grid charging or scheduled export. | $512 supply + $977 usage − $33 FiT = $1,456 |
| 2 | Alinta – HomeDeal Smart | $1,912 | $1,563 | $508 dearer | $349 cheaper | Self-Powered; 20% reserve; no grid charging or scheduled export. | $617 supply + $979 usage − $33 FiT = $1,563 |
| 3 | Alinta – SolarBalance Ready | $2,008 | $1,680 | $625 dearer | $328 cheaper | Self-Powered; 20% reserve; no grid charging or scheduled export. | $680 supply + $1,079 usage − $79 FiT = $1,680 |
| 4 | Red Energy – Living Energy Saver | $2,090 | $1,686 | $631 dearer | $403 cheaper | Self-Powered; 20% reserve; no grid charging or scheduled export. | $602 supply + $1,100 usage − $16 FiT = $1,686 |
| 5 | Red Energy – Qantas Red Saver | $2,090 | $1,686 | $631 dearer | $403 cheaper | Self-Powered; 20% reserve; no grid charging or scheduled export. | $602 supply + $1,100 usage − $16 FiT = $1,686 |
| 6 | AGL – Battery Rewards Plan | $1,120 | $1,698 | $643 dearer | $578 dearer | Self-Powered; 20% reserve; no grid charging or scheduled export. | $617 supply + $1,132 usage − $51 FiT = $1,698 |
| 7 | AGL – Smart Saver | $1,357 | $1,717 | $662 dearer | $360 dearer | Self-Powered; 20% reserve; no grid charging or scheduled export. | $617 supply + $1,133 usage − $33 FiT = $1,717 |
| 8 | Origin – Go Variable Ongoing | $1,346 | $1,719 | $664 dearer | $373 dearer | Self-Powered; 20% reserve; no grid charging or scheduled export. | $623 supply + $1,145 usage − $49 FiT = $1,719 |
| 9 | OVO – The Basic | $1,335 | $1,720 | $665 dearer | $385 dearer | Self-Powered; 20% reserve; no grid charging or scheduled export. | $538 supply + $1,214 usage − $33 FiT = $1,720 |
| 10 | Red Energy – Living Energy Solar Saver | $2,103 | $1,732 | $677 dearer | $371 cheaper | Self-Powered; 20% reserve; no grid charging or scheduled export. | $701 supply + $1,113 usage − $81 FiT = $1,732 |
| 11 | Red Energy – Qantas Red Solar Saver | $2,103 | $1,732 | $677 dearer | $371 cheaper | Self-Powered; 20% reserve; no grid charging or scheduled export. | $701 supply + $1,113 usage − $81 FiT = $1,732 |
| 12 | Red Energy – Red BCNA Saver | $2,103 | $1,732 | $677 dearer | $371 cheaper | Self-Powered; 20% reserve; no grid charging or scheduled export. | $701 supply + $1,113 usage − $81 FiT = $1,732 |
| 13 | Red Energy – Red Wildlife Saver | $2,103 | $1,732 | $677 dearer | $371 cheaper | Self-Powered; 20% reserve; no grid charging or scheduled export. | $701 supply + $1,113 usage − $81 FiT = $1,732 |
| 14 | AGL – Netflix Plan | $1,374 | $1,735 | $679 dearer | $360 dearer | Self-Powered; 20% reserve; no grid charging or scheduled export. | $634 supply + $1,133 usage − $33 FiT = $1,735 |
| 15 | Origin – Solar Boost Variable | $1,340 | $1,764 | $708 dearer | $423 dearer | Self-Powered; 20% reserve; no grid charging or scheduled export. | $649 supply + $1,193 usage − $78 FiT = $1,764 |
| 16 | Powershop – Switch Saver | $1,373 | $1,769 | $714 dearer | $396 dearer | Self-Powered; 20% reserve; no grid charging or scheduled export. | $503 supply + $1,283 usage − $16 FiT = $1,769 |
| 17 | AGL – Solar Savers | $1,352 | $1,774 | $719 dearer | $421 dearer | Self-Powered; 20% reserve; no grid charging or scheduled export. | $649 supply + $1,192 usage − $68 FiT = $1,774 |
| 18 | Alinta – Standing Offer | $2,180 | $1,781 | $726 dearer | $399 cheaper | Self-Powered; 20% reserve; no grid charging or scheduled export. | $701 supply + $1,113 usage − $33 FiT = $1,781 |
| 19 | Red Energy – Solar Sharer Offer | $1,225 | $1,784 | $729 dearer | $560 dearer | Self-Powered; 20% reserve; no grid charging or scheduled export. | $649 supply + $1,217 usage − $81 FiT = $1,784 |
| 20 | OVO – The Basic Free 4 | $1,218 | $1,789 | $734 dearer | $571 dearer | Self-Powered; 20% reserve; no grid charging or scheduled export. | $579 supply + $1,226 usage − $16 FiT = $1,789 |
| 21 | Origin – Everyday Rewards Variable | $1,405 | $1,793 | $738 dearer | $387 dearer | Self-Powered; 20% reserve; no grid charging or scheduled export. | $649 supply + $1,193 usage − $49 FiT = $1,793 |
| 22 | Origin – Standing Solar Sharer | $1,276 | $1,817 | $762 dearer | $541 dearer | Self-Powered; 20% reserve; no grid charging or scheduled export. | $649 supply + $1,217 usage − $49 FiT = $1,817 |
| 23 | Energy Locals – Solar Sharer Offer | $1,353 | $1,866 | $811 dearer | $513 dearer | Self-Powered; 20% reserve; no grid charging or scheduled export. | $649 supply + $1,217 usage − $0 FiT = $1,866 |
| 24 | Flow Power – 4Free | $1,730 | $2,309 | $1,254 dearer | $579 dearer | Self-Powered; 20% reserve; no grid charging or scheduled export. | $845 supply + $1,469 usage − $6 FiT = $2,309 |
| 25 | Flow Power – Happy Hour | $2,757 | $2,445 | $1,390 dearer | $311 cheaper | Self-Powered; 20% reserve; no grid charging or scheduled export. | $845 supply + $1,610 usage − $10 FiT = $2,445 |
A “cheaper” basic-vs-recorded result only means that generic Self-Powered behaviour suited that particular alternative tariff better than the home’s recorded battery behaviour. Every basic-mode alternative was still more expensive than Amber’s $1,055 ongoing result.
How to find the best solar-and-battery electricity plan anywhere in Australia
The retailer names in this case study are less important than the method. Before choosing a plan in Queensland, New South Wales, Victoria, South Australia, Western Australia, Tasmania, the ACT or the Northern Territory, check these six items against your own interval data.
- Confirm postcode and network availability. A plan advertised nationally may have different rates—or may not be offered—on your local distribution network.
- Calculate the annual supply charge. A strong feed-in rate can be outweighed by a high fixed daily charge.
- Map imports by tariff period. Know how much electricity you buy during peak, shoulder, off-peak and free windows.
- Read feed-in conditions carefully. Check daily caps, time windows, system-size limits, battery-export conditions and virtual power plant requirements.
- Confirm what the battery can actually do. Grid charging, scheduled export, inverter power, usable capacity, backup reserve and export limits all affect the result.
- Model battery efficiency and realistic control. Do not assume every purchased kilowatt-hour can be sold later, or that a basic app setting will reproduce a sophisticated dispatch strategy.
The best electricity plan is therefore not simply the one with the highest solar feed-in tariff. It is the plan whose entire rate structure matches the home’s solar production, consumption profile, battery hardware and control system.
Frequently asked questions
What is the best electricity retailer for solar and battery owners in Australia?
There is no universal winner. The best retailer depends on postcode, network, household interval data, solar production, battery capacity, export limits and the battery’s control options. In this Brisbane/Energex case study, AGL Battery Rewards was the lowest tariff-aware result, while Amber was better than every alternative when the battery used basic Self-Powered operation.
Is Amber Electric worth it for a home with solar and batteries?
It can be. Amber’s ongoing cost for this home was approximately $1,055, and its actual cost after $440 in separate credits was about $615. Amber outperformed every alternative when those alternatives used basic battery control. However, several structured retail plans were cheaper when the battery was deliberately optimised around their free, off-peak and premium export windows.
Does the highest solar feed-in tariff produce the lowest electricity bill?
Not necessarily. Daily supply charges, import prices, feed-in caps, export windows and battery losses can outweigh a headline feed-in rate. Flow Power Happy Hour offered up to 35c/kWh during its evening window but still produced one of the highest annual costs in this case study.
Can a home battery charge from the grid and export that electricity later?
Some systems and retail plans allow it, while others impose technical, contractual or virtual power plant conditions. The relevant retailer rules, distribution-network export limit and battery-control method must be confirmed. Where permitted in this analysis, the model included grid charging, storage losses and later export—it did not assume simultaneous buying and selling.
Are free electricity periods valuable for battery owners?
They can be highly valuable if the battery is deliberately filled during the free period and used later. In this case study, OVO Free 4 modelled at $708 with tariff-aware control but $1,789 in basic Self-Powered mode. A free window has limited value if the battery does not charge during it.
Why keep a 20% battery backup reserve?
The reserve preserves some stored energy for an outage rather than using the entire battery for bill optimisation. A different reserve would change both backup duration and the energy available for tariff shifting. This analysis kept the reserve at 20% in every modelled plan.
Can I reproduce these tariff-aware results using only the Tesla app?
Not always. Basic time-of-use charging may be achievable through standard controls, but precise forced-export schedules can require retailer integration, virtual power plant participation or a compatible external energy-management platform. Hardware compatibility and plan permission should be confirmed before relying on a modelled result.
Should battery degradation be included when comparing electricity plans?
It should be considered when assessing complete battery lifetime economics. This article isolates the retail electricity bill, so no wear cost was added. A plan that creates heavy battery cycling may have a lower bill without necessarily producing the best whole-of-life financial outcome.
The practical conclusion
For a solar-and-battery household, choosing a retailer without considering battery control can produce the wrong answer. In this case study, Amber performed extremely well against every alternative under basic battery operation. Once deliberate grid charging and permitted high-value export were introduced, 13 alternatives became clearly cheaper.
That does not make one retailer universally best. It shows why solar, battery capacity, inverter power, backup reserve, tariff selection and ongoing control need to be considered as one energy system.
GI Energy’s role is to help homeowners make that decision with realistic expectations and a system designed around their property, energy use, financial goals, backup needs and future plans.
Method and pricing note: This is an evidence-based case study, not personal financial advice or a promise of future savings. Retail rates, plan availability, eligibility, export rules and government programs can change. Results will vary with location, weather, roof orientation, shading, household demand, battery settings and equipment. Confirm current plan documents and obtain advice relevant to your property before acting.
