Most Perth households have spent more time choosing their internet plan in the past decade than choosing their electricity tariff. That made sense when there was only one tariff worth considering. It does not make sense any more. The gap between Synergy’s flat Home Plan A1 and its time-of-use Midday Saver is now wide enough that the wrong choice can quietly subtract three to four years off the payback of a brand-new battery. The right choice can move that battery from a slow win to a genuinely fast one.
This is a guide to making that choice on the basis of evidence rather than habit.
Figure 1: Synergy Home Plan A1 (flat) compared with Midday Saver (time-of-use) across a 24-hour day.
Why the Tariff Decision Now Matters More Than the Battery Brand
In 2020, Synergy’s residential rates sat in a tight band. A1 was the obvious default and a time-of-use plan saved at the margins. Five years later, the picture is unrecognisable. The A1 rate has climbed to 32.3719 cents per kilowatt-hour. The Midday Saver’s super off-peak window now sits at 8.6151 cents – a quarter of A1. Its peak window has risen to 53.8446 cents – well over six times super off-peak. All figures are GST-inclusive and effective 1 July 2025, and they are set by the WA State Government rather than negotiated.
That spread is the entire reason a battery now pays back inside its warranty in Perth. Every kilowatt-hour you can move from the 3pm–9pm peak window into the 9am-3pm super off-peak window is worth roughly 45 cents. The asset that does that moving – a properly sized battery – earns its keep entirely from the tariff structure underneath it. The battery is the engine; the tariff is the fuel.
There is one more catalyst Perth households need to factor in. From 1 May 2026, Western Australia’s connection rules change for new and upgraded systems on the SWIS. The new Wholesale Electricity Market Procedure published by Western Power lifts the standard-connection inverter cap to 30 kVA aggregate and introduces a two-pathway export model: full export with CSIP-AUS communications, or a fixed 1.5 kW export limit. The federal Cheaper Home Batteries Program also moves to a tiered STC structure on the same date. Both changes reshape how a battery should be sized – and they make the tariff that battery operates under more, not less, important.
The Three Synergy Residential Tariffs in Plain Numbers
There are three plans worth knowing about for a Perth household considering solar or storage. All three carry the same daily supply charge of 116.0505 cents.
Figure 2: The three Synergy residential tariffs at a glance. Same supply charge across all plans.
Home Plan A1 – the default. One rate, all day, every day: 32.3719 c/kWh. The dishwasher costs the same at 11am as it does at 6pm. There are no time windows to manage. For a household whose consumption is genuinely flat across the day, A1 is the simplest plan available and often the cheapest as well.
Midday Saver – the time-of-use option. Three windows on a structure that repeats every day, including weekends and public holidays: 8.6151 c/kWh super off-peak (9am-3pm), approximately 22 c/kWh off-peak (9pm-9am), and 53.8446 c/kWh peak (3pm-9pm). For 18 hours of every day you pay less than A1. For six hours you pay considerably more. The plan rewards households that can either shift consumption out of the evening peak or store cheap daytime energy to spend in the evening.
EV Add-On – the overnight extender. Includes everything in Midday Saver and adds a dedicated overnight band from 11pm to 6am at 19.3841 c/kWh. To qualify a household must have a battery-electric or plug-in hybrid vehicle registered to the address. For households with an EV that charges overnight, this rate is worth around $1.50 per 100 km – roughly an eighth the cost of petrol.
A useful framing: the difference between A1 and Midday Saver is not the daily supply charge or any switching fee. It is whether your home can keep its evening grid draw small and whether you have an asset that can shift load. Without that asset, time-of-use plans tend to punish solar households rather than reward them.
The Four Household Profiles – Which Tariff Wins
Most decision matrices on this topic compare averages. That obscures the real answer, because the Midday Saver’s six peak hours behave very differently to its eighteen non-peak hours. A clearer way to think about it is to identify which of four profiles your household sits in.
Figure 3: Decision matrix across four common Perth household profiles. .
No solar, no battery. A1 usually wins. The Midday Saver only pays off if you can keep evening grid draw under roughly 30% of total consumption – achievable for shift workers, frequent evening absentees, or households running pool pumps and dishwashers on timers – but for the typical family of four arriving home at 5pm and running aircon until 9pm, A1 stays cheaper.
Solar only. A1 usually wins, and the gap is wider than most homeowners expect. Self-consumed midday solar offsets only the cheap 8.6c super off-peak rate on Midday Saver, while every kilowatt-hour drawn from the grid in the evening costs 53.8c instead of 32.4c. A typical 6.6 kW solar home consuming around 25 kWh per day comes out roughly $30-$50 a year worse off on Midday Saver than on A1, before any DEBS feed-in is considered. SolarQuotes’ Finn Peacock reached the same conclusion in a 2024 analysis of Perth solar households, and our own field data across 45,000-plus installations supports it.
Solar plus battery. Midday Saver wins, decisively. This is the household profile where the tariff structure earns its name. A 10 kWh battery charged from solar during the day and discharged across the 3pm-9pm window can avoid 8 to 10 kWh of peak imports – roughly $3.50 to $4.50 a day, $1,200 to $1,600 a year – that an A1 household cannot capture. Combined with self-consumption of midday solar that would otherwise export to the grid at 2c/kWh under DEBS, the Midday Saver moves the battery’s payback period from 7-9 years on A1 to around 4-6 years on this plan, depending on system sizing and household consumption.
Solar plus battery plus EV. EV Add-On is the right answer. The overnight 19.4c window matters because it lets a household top up its EV without compromising battery state-of-charge for the morning. For a typical Perth commuter driving 15,000 km a year, charging on the EV Add-On replaces roughly $1,500-$2,000 a year of petrol with about $300-$400 a year of overnight grid power. Stacking that against the battery’s peak-shifting savings, total annual energy cost reductions for this profile sit comfortably above $4,000 against an A1 baseline.
Figure 4: A battery converts the cheap-window solar surplus into peak-window self-consumption – the entire payback engine.
A Worked Example: 10 kWh Battery on Midday Saver
A Perth family of four with a 10 kW solar system, a 10 kWh battery, and average consumption of 24 kWh per day. Without the battery, on A1, their evening import (3pm–9pm) is around 9 kWh – roughly $2.91 per day at 32.4c – and overnight grid draw adds about $1.30 a day. Daytime consumption is mostly covered by solar.
On Midday Saver with the battery cycling once daily – charging from surplus solar in the super off-peak window and discharging across the peak window – that 9 kWh of evening grid draw is displaced by stored solar. The remaining 4 kWh of overnight consumption costs roughly $0.88 at the off-peak rate.
Figure 5: Daily and annual electricity spend, same Perth household, two tariff structures.
Total daily grid spend on this profile drops from around $4.20 on A1 to under $1 on Midday Saver, net of supply charge. Adding the daily supply charge of $1.16, annual electricity spend falls from approximately $1,960 to around $750 – a saving of roughly $1,200 a year before any Synergy Battery Rewards activation credits or DEBS export income are added.
After the WA Residential Battery Scheme rebate (up to $1,300 for Synergy customers on a 10 kWh system), the federal Cheaper Home Batteries Program contribution, and the Plenti interest-free loan facility, payback for this household lands inside the 5-year mark. After tomorrow’s federal STC step-down on 1 May, the same payback profile shifts by roughly six months – meaningful, but well within the battery’s 10-year warranty either way.
The Two Things That Will Trip You Up
Two technical points genuinely catch homeowners out and deserve flagging.
The first is DEBS asymmetry. Synergy’s Distributed Energy Buyback Scheme pays just 2 cents per kilowatt-hour for solar exported between 9am and 3pm – exactly when most rooftop solar generates – and 10 cents per kilowatt-hour for the 3pm-9pm window. On a Midday Saver tariff, exporting midday surplus is worth a fraction of self-consuming it via a battery later. This is why a sized-correctly battery, not a bigger solar array, is now the financially superior next move for most Perth households with existing solar.
The second is peak overrun. A 10 kWh battery covers most evening consumption for a typical four-person household, but not all. Households with pools, multiple split-systems, or strong evening cooking patterns can routinely exceed 12-15 kWh of evening draw in summer. If your battery empties at 7pm, the remaining peak hours cost 53.8c per kilowatt-hour, fast. The decision then is whether to oversize the battery – easier under the new 30 kVA SWIS standard-connection allowance – or accept the tail risk.
How to Decide Without Guessing – The 30-Minute Audit
The Synergy My Account portal lets every household with an Advanced Metering Infrastructure (AMI) meter download interval data showing consumption by hour. Thirty minutes with that data tells you what no installer’s spreadsheet can: your actual evening consumption profile, your typical solar-export shape, and the precise amount your household pays during the 3pm–9pm window today.
For most Perth homes considering a battery, the right starting point is to run that audit before signing any contract. The question is not “is Midday Saver cheaper” — it is “what does my load profile do under each tariff, with and without a battery”. The answer is rarely intuitive and almost always specific to the household.
Free Tariff and Battery Audit — Regen Power offers this audit free for any Perth household, whether your existing system was installed by us or not. Our consultants will pull the interval data, model both tariffs against your actual load profile, and provide a written recommendation that includes battery sizing under the new post-1-May SWIS rules. Book a free assessment at regenpower.com/contact or call 08 9456 3491.
Frequently Asked Questions
Is Midday Saver cheaper than Home Plan A1 in Perth?
It depends on your load profile. Midday Saver offers cheaper rates for 18 hours a day and a much higher rate for the six-hour 3pm-9pm peak. Households that can shift consumption out of the evening – through a battery, daytime appliance use, or simply being absent – generally come out ahead. Households whose consumption is concentrated between 5pm and 9pm typically pay more on Midday Saver than they would on A1.
Should I switch to Midday Saver if I have solar but no battery?
Usually, no. Self-consumed midday solar only offsets the cheap super off-peak rate, while evening grid draw becomes considerably more expensive. For a typical Perth solar household consuming 20-25 kWh per day, A1 generally remains the better tariff until a battery is added.
Does Midday Saver require a smart meter?
Yes. Midday Saver requires an Advanced Metering Infrastructure (AMI) meter, which is now installed as standard in most Perth suburbs. If your suburb does not have AMI yet, Synergy will reprogramme or replace your existing meter when you switch.
Can I switch back to A1 if Midday Saver doesn’t work for me?
Yes. Synergy allows free switching between tariffs with five business days’ notice. There is no lock-in period and no termination fee. We recommend running an audit at the 90-day mark to confirm the tariff change is delivering the expected savings.
How does the new 1 May 2026 federal rebate change affect this maths?
The federal Cheaper Home Batteries Program moves to a tiered STC structure on 1 May 2026, reducing the upfront discount on a 10 kWh battery by approximately $700-$900 compared to a pre-deadline install. The arithmetic above still works – Midday Saver remains the right tariff for solar-plus-battery households – but battery payback periods extend by roughly six months across most Perth profiles. The WA Residential Battery Scheme rebate of up to $1,300 for Synergy customers and the Plenti zero-interest loan facility are unaffected.
About the Author
Dr Nikhil Jayaraj is the Managing Director of Regen Power and a Research Adjunct at Curtin University. He has published peer-reviewed research in Energy Policy on the dynamics of electric vehicle adoption and residential solar storage, and has led the design of more than 45,000 solar, battery and EV-charging installations across Western Australia. Regen Power was awarded #1 Most Popular Solar Installer in Western Australia at the SunWiz Awards 2026, ProductReview Award winner six consecutive years (2021–2026), Sunwiz Best Rated Solar Company 2025, and EUPD Top Brand PV Installer 2023 and 2024.
