Synergy billing, decoded

How your Perth electricity bill works

Every Synergy bill is assembled from the same handful of numbers. Learn what each one is, which ones you actually control, and where to look first when the total jumps.

The anatomy

Four numbers make up the charges

The standard tariff charges for the period come from these four, before any optional extra you have signed up for

Number 1

60 daysa typical period

Synergy bills roughly every two months, not monthly. The period length multiplies the supply charge below, and it sets how much usage the bill covers. A short or long one makes a bill incomparable to the last.

Number 2

$1.1924per day, supply charge

A fixed daily charge for the grid connection itself. It applies every day of the period, whether you use power or not. Solar doesn't touch it.

Number 3

kWh used× 33.26c on A1

The consumption charge. Your plan fixes the rate, so the kWh are the part your habits and your appliances actually move. That's the number worth chasing when a bill runs high.

Number 4

Credits

Anything subtracted from the charges. Solar export credits, concessions, and any state credit applied to your account all land here.

The arithmetic, on the flat A1 rate: (days in the period × supply charge) + (kWh used × your usage rate), less any credits. On a time-of-use plan the second term splits: the kWh in each rate band gets multiplied by that band's own rate and the bands are summed. On a 60-day A1 bill the supply charge alone is about $72 before you switch a single light on.

GST is not a fifth number. It sits inside the two charges above rather than beside them, which is why your bill can show a subtotal with the tax on its own line and still reconcile to the same total.

One thing those four don't cover: the figure at the very bottom of the page. The amount due also carries whatever was left over from your last bill, plus any payment since. It's your account position, not just this period's charges.

Two households on the same plan with the same usage get the same charges. When a bill looks wrong, one of those four numbers has moved. The sections below take them in turn.

The document

Where each number appears on the page

A Synergy bill runs to several sections, and only a few are worth slowing down for

Account summary: Account number, billing period, current charges, previous balance. Check the period length first: a short or long period makes the total incomparable to your last bill, and that alone explains a lot of bill shocks.
Meter reading: Previous read, current read, units consumed, and the read type. An estimated read means the figure is modelled rather than measured. The next actual read corrects it, so the difference lands on a later bill.
Charges breakdown: The supply charge and the usage charge, each shown with its rate. Your tariff code appears on the bill too, and that's how you confirm which plan you're actually on.
Credits: Export credits for solar households, concession lines for eligible households, and any account credit. These reduce the amount payable, not the usage recorded.
Usage comparison: The bar graph against the same period last year, plus an average daily use figure. A jump you can't explain by the season or by a change at home is worth chasing.

Every line item on a Synergy bill decodes the sections in order. Prefer working from the layout on the page instead of the concepts? How to read your Synergy bill walks the document top to bottom. The plain-English bill reading guide covers what to check before you pay.

The drivers

What actually drives the total

Usage is the only number most households can move, and it moves in three ways

The three levers

Baseload: The always-on draw: fridge, pool pump, hot water, modem, standby devices. It runs 24 hours a day, so a small reduction compounds across the whole period.
Big intermittent loads: Reverse-cycle heating and cooling, hot water, and an electric vehicle if you have one. These are seasonal, which is why a summer bill and a spring bill are barely the same document.
Timing: On Midday Saver, timing is most of the bill: 55.33c at 6pm against 8.85c at noon, for the same kWh. On a flat rate it's worth nothing to a household without solar. With solar it still pays, because a load moved into daylight runs on your own output instead of buying at the full rate, and self-consumed power is worth far more than exported power.

Before you decide your usage is high, check it against comparable homes. Perth household consumption benchmarks give figures by home size and by season. Once you know the total really is high, the running cost of each appliance shows where the kWh are actually going, which is rarely where people assume.

The evidence

Your half-hourly interval data

The bill is a summary. The interval data behind it is the actual record, and it's free

Western Power has been rolling out smart meters across Perth since 2012. If your home has one, it records consumption every 30 minutes, and records solar export at the same granularity. That's 48 readings a day for each channel, roughly 17,500 a year, and it settles most questions a bill can only hint at.

Getting the file

1
Log in to Synergy's MyAccount using the account details on your bill.
2
Open your usage history and look for the detailed or half-hourly view rather than the monthly summary.
3
Choose a date range and download it as a CSV. Requests are typically capped at 12 months, so pull two ranges if you want a longer history.
The file gives you an interval start time, the kWh imported in that interval, and the kWh exported if you have solar.

What to look for once you have it

Your daily shape: Where the peaks land on a weekday against a weekend. A household that uses most of its power between 9am and 3pm wants a different plan from one that uses it between 6pm and 9pm, and the file settles which one you are.
Overnight minimum: The lowest half-hourly reading between midnight and 5am, doubled, is close to your baseload in kW: the load that never switches off. Take a steady 0.3 kW draw, the kind a pool pump or an older hot water system leaves running. Modelled at the A1 rate, that's $874 a year before anyone turns anything on. Finding and cutting baseload is usually the most productive thing the data tells you.
Export profile: For solar homes: when generation peaks on your roof, whether you're hitting the export limit, and how winter compares to summer. That last one is how you check an installer projection against reality.

No smart meter? An older accumulation meter records only the total since the last read, with no time-of-day detail, so none of the above is available. Western Power is still rolling smart meters out, so it's worth asking whether your street is scheduled.

Your inverter app and your meter will usually disagree by a percent or three, because they measure at different points in the system. A gap that size is normal. The meter is the billing record, so when the two differ, the meter is the one that counts.

Going further with the file, including pulling it from Western Power directly and reading it alongside your inverter data, is covered in how to read your smart meter data.

The plan

The plan you're on, and the one choice you have

You can't change retailer in Perth. You can change plan

Flat rate against time of use

A1, the flat rate: 33.26c/kWh at every hour of every day, on a $1.1924 daily supply charge. Simple, and usually the safer plan when your usage is spread out or lands in the evening. The panel below is how you confirm that rather than assume it.
Midday Saver, time of use: 8.85c/kWh from 9am to 3pm, 55.33c/kWh from 3pm to 9pm, and 24.34c/kWh the rest of the time, on a $1.3278 daily supply charge. The midday rate is the draw and the evening rate is the risk. Its 3pm to 9pm peak is the same window DEBS pays its higher export rate in, which matters if you have solar.

How to decide without guessing: take a year of interval data, price every half hour under both plans, then add each plan's own daily supply charge before you compare. The supply charges aren't the same, so a usage-only comparison can point a near-even household at the more expensive plan. Over a year the supply gap alone is worth about $49.

Comparing those two head to head is its own job: Midday Saver against A1 works the sums through. Still on Smart Home, which you can no longer sign up for? Who the Smart Home plan suits covers whether it's worth staying on. Wondering why none of this involves shopping around? Whether Perth households can switch electricity provider explains what the WA market allows, and where gas differs from power.

The credits

Export credits: DEBS and REBS

Solar households can receive export credits, and the applicable scheme depends on the circumstances of their connection and assessment

REBS, the Renewable Energy Buyback Scheme, pays one flat rate at any hour. DEBS, the Distributed Energy Buyback Scheme, pays more in the late afternoon and very little the rest of the day. The switch runs one way only: a household that moves off REBS can't move back. Eligibility and scheme status depend on the applicable Synergy and WA conditions, so confirm your own status with Synergy or the WA Government before relying on this summary.

Neither of these is the old 40c rate. If you have seen a figure like that quoted for early Perth solar, it came from the original feed-in tariff, a separate scheme that locked a high rate in for a small group of very early adopters and closed to new applicants in 2011. It has no bearing on what REBS or DEBS pay today. The history of WA feed-in tariffs covers how the three differ.

The two schemes side by side

REBS rate: 7.135c/kWh flat, at every hour, with no daily cap. Closed to new connections.
DEBS rate: 10c/kWh at peak, meaning 3pm to 9pm, and 2c/kWh off-peak at all other hours, on the first 50 kWh of combined export per day. It applies to all metered export, whether that comes from solar, a battery, or both.
Who is on which: REBS for systems connected before 6 November 2020 that haven't been altered. DEBS for everything since, and for anyone who has switched voluntarily.
Reversible: No. Leaving REBS is permanent, and adding panels, upsizing an inverter, or connecting a battery can move you off it without you asking.

Which one pays more

It comes down to when your export leaves the meter. North-facing panels push most of their output out between 10am and 2pm, which sits in the off-peak window, so REBS pays more for that shape: 5.13c more per kWh. West-facing panels, or a battery discharging into the evening, put more into peak, where DEBS pays 2.87c more per kWh than REBS. That narrows the gap. On the shares this page models it doesn't close it: DEBS only overtakes REBS once more than 64% of your export lands in peak.

Take a north-facing system exporting around 3,000 kWh a year with no battery. On a modelled 15/85 split between peak and off-peak, the same volume prices out very differently:

Paid under REBS: $214/year
Paid under DEBS: $96/year

The verdict

$118/year

What REBS is worth to this system

Modelled for a north-facing array with no battery, exporting 3,000 kWh a year on a 15/85 peak/off-peak split. A west-facing array or a battery shifts export into peak and shrinks the gap. Your own split comes out of your interval data.

How to check which one you're on

Your bill says so directly. Look in the credits section for either a single REBS line at the flat rate, or a pair of DEBS lines split into peak and off-peak. If the bill is ambiguous, MyAccount shows the same detail against your billing history.

Once you know which one applies, how the DEBS rate is calculated and billed goes into the mechanics. The DEBS strategy guide shows the generation curve the time split above comes from, and self-consuming against exporting covers why the export credit is the smaller half of the decision.

Before you change anything on the roof: if you're on REBS and it is worth keeping, confirm with Synergy and your installer in writing before adding panels, replacing an inverter with a larger one, or connecting a battery. Any of those can trigger a new connection application, and the assessment lands on DEBS.

The reductions

Credits, concessions, and how you pay

Some of the largest reductions on a Perth bill have nothing to do with using less

Worth checking once a year

Concession eligibility: WA runs several concession and hardship programs, and they are claimed rather than granted automatically. A card that arrived after you set up the account won't apply itself.
How you pay: Direct debit, smoothed payments, and pay-on-receipt change the cash-flow shape of a bill without changing what you owe. Smoothing is useful against the summer spike, but it hides consumption changes.
GreenPower: No roof of your own? GreenPower is one lever renters and apartments still have. You pay a premium on top of your usage charge and Synergy matches your consumption with renewable generation. It's an addition to the bill, not a reduction.

WA electricity concessions and who qualifies lists each program and how to claim it. For payment terms and billing cycles, see how Synergy billing and direct debit work. Weighing renewable supply without a roof of your own? What GreenPower costs and what it does shows what you get for the premium.

Case file · your bill

Put your own bill through it

Reading the bill tells you where the money went. Running your figures tells you what changes if you move plan, shift load, or add solar.

Check a bill Model your savings

Rates on this page come from the current Synergy and WA export schedules.