How Synergy's billing cycle works in Perth — especially with solar

Synergy bills Perth residential customers every two months — a billing period of approximately 60–63 days. This is longer than many eastern states electricity retailers (which bill monthly), which means Perth bills can feel larger simply because they cover a longer period. Here's how the cycle works, and what changes when you add solar.

The standard Synergy billing period

Synergy's residential billing periods are approximately:

• Period 1: Early January to early March (~60 days)
• Period 2: Early March to early May (~60 days)
• Period 3: Early May to early July (~62 days)
• Period 4: Early July to early September (~62 days)
• Period 5: Early September to early November (~61 days)
• Period 6: Early November to early January (~62 days)

Exact dates vary by your meter read schedule, which is assigned by Western Power (the network operator) rather than Synergy. Your bill shows the "Billing Period" with start and end dates.

The bimonthly structure means:

• Summer bills (covering November–January and January–March) are for the highest consumption months — these bills can be 30–50% higher than winter bills for households with air conditioning
• Winter bills (May–September) typically show lower consumption and often show higher DEBS export earnings (per-bill, at least — winter export rates are the same but total solar generation is lower)

Meter reads: actual vs estimated

Western Power reads your meter (or your smart meter transmits data) approximately once every two months to generate your bill.

Smart meters (most Perth homes since approximately 2016 onward): Smart meters transmit 30-minute interval data automatically. Your bill is always based on actual consumption — no estimated reads.

Accumulation meters (older homes or meters awaiting upgrade): Western Power may perform actual reads every billing period, or alternately perform actual reads and estimated reads. An estimated bill is calculated from your historical usage pattern.

How to identify an estimated bill: Look for "Estimated" or "E" next to the meter read line on your bill. If you've just installed solar, an estimated bill won't reflect your actual solar export earnings — contact Synergy to request an actual read for the period solar was commissioned.

The solar billing difference: credits, not offsets

Before solar, your Synergy bill is straightforward: supply charge (daily) + consumption charge (per kWh) = total.

After solar with DEBS, your bill has additional line items:

Import consumption: The electricity you drew from the grid (now usually less than before solar).

DEBS Super Off-Peak export credit: The electricity you exported between 9am–3pm, credited at 10c/kWh. This appears as a negative amount (a credit).

DEBS Off-Peak export credit: The electricity you exported at other times, credited at 2c/kWh. Also a credit.

Total: If your credits exceed your charges in a billing period (possible in spring when generation is high and consumption is low), you'll have a credit balance rather than an amount owing.

Credit balances and rollovers

If your solar + DEBS credits exceed your consumption charges in a billing period, Synergy carries the credit forward to the next billing period. This credit accumulates across periods — it doesn't expire.

Annual reconciliation: Once per year, if you have a sustained credit balance, Synergy will offer to pay it out (typically via bank transfer or cheque). You don't have to wait — you can request a credit payout at any time by calling Synergy.

Tax note: DEBS credits are generally not subject to GST for residential customers and do not need to be declared as income for tax purposes (they're a reduction of your electricity cost, not a separate income stream). However, the tax treatment of solar income for investment properties or businesses differs — consult a tax advisor for those scenarios.

When solar is first commissioned: the transition billing period

The billing period when your solar is first commissioned is a partial-period: solar started generating partway through the billing period.

What to expect:

• Your first post-solar bill will show a partial period of grid-only consumption, then a partial period of solar consumption and DEBS exports
• The meter changeover date (when Western Power switches your meter to two-way measurement) is often 2–6 weeks after commissioning — during this gap, your solar exports may not be recorded
• DEBS credits start from the date of the meter changeover, not the commissioning date

Claim lost DEBS credits: If there's a gap between commissioning and meter changeover, your exports during that period weren't recorded. Synergy will typically not backpay these credits — the gap is an industry-known friction point. Minimise it by ensuring your installer lodges the generation meter notice promptly and follows up with Western Power.

Verifying your Synergy bill with solar

Steps to verify your DEBS credits are correct:

1. Get your inverter's export data for the billing period from your monitoring app (Fronius SolarWeb, Sungrow iSolarCloud, Goodwe SEMS, etc.)
2. Calculate expected credits: (Super Off-Peak exports × $0.10) + (Off-Peak exports × $0.02)
3. Compare to your Synergy bill — note that inverter monitoring and Synergy's meter may differ by a small margin (~1–3% is typical from rounding and measurement calibration)

If the discrepancy is large (>5%), your DEBS credits may be incorrectly calculated. Contact Synergy with your inverter export report. If Synergy can't resolve it, lodge a complaint with the Energy and Water Ombudsman WA (EWOWA) — metering and billing disputes are within EWOWA's scope.

Understanding your supply charge

The daily supply charge (~$1.28/day in FY2026–27) is fixed regardless of consumption or solar generation. For a 60-day billing period, this adds approximately $76.80 to every bill before any consumption or export charges. Solar does not reduce the supply charge.

Some Perth solar households express frustration that their supply charge remains even when their DEBS credits might cover most consumption charges. The supply charge is the network access fee — it pays for the poles, wires, and meter — and is separate from energy pricing. It exists on all tariffs and is not affected by solar.

Synergy bills Perth households every two months (~60 days), with bills covering summer months typically significantly higher than winter. With DEBS solar, credits appear as negative line items and roll forward if they exceed charges. Verify credits against your inverter's export data. The transition billing period when solar is first commissioned often involves a delay between commissioning and meter changeover — DEBS credits start from the meter changeover date.