How to Read Your Synergy Bill as a Solar Owner (2026)

A Synergy bill is confusing enough without solar. Add panels, a feed-in credit and a time-of-day export scheme, and most people give up and just look at the total.

That is a mistake, because your bill contains everything you need to know about whether your solar system is actually doing its job. Here is how to read it properly.

The lines that matter

Supply charge. A fixed daily amount for being connected to the network. You pay this whether you use any electricity or not, and solar does not reduce it. If your bill has dropped a lot but not to zero, this is usually why.

Consumption (kWh purchased). Electricity you drew from the grid. With solar, this should be concentrated in the evening, overnight and on overcast days.

Feed-in credit / DEBS credit. Payment for solar you exported to the grid. Under the Distributed Energy Buyback Scheme this is split by time of day, with a higher rate for energy exported during the evening peak window and a much lower rate outside it.

Total. Consumption charges plus supply charge, minus your feed-in credit.

The three numbers that tell you if your system is working

Forget the total for a moment. These three tell the real story.

1. Your self-consumption ratio

This is the proportion of your generated solar that you used yourself rather than exporting.

Because you buy electricity back at many times what you are paid for exports, every kilowatt-hour you self-consume is worth far more than one you export. This single ratio drives most of the financial outcome of a solar system in WA.

If you are exporting the large majority of what you generate, your system is producing well but you are capturing very little of its value. The fixes, in order of cost: shift appliance timing into daylight hours, then consider storage.

2. Your evening grid draw

How much you are buying between roughly 4pm and 10pm. This is your most expensive electricity and the hours your panels cannot help with.

A high evening draw is the classic signature of a household that would benefit from a battery — you are buying back at a high rate the energy you sold cheaply six hours earlier.

3. Generation versus expectation

Compare your export plus estimated self-consumption against what your system should produce. In Perth, a well-oriented system should produce roughly 4–4.5 kWh per kW of installed capacity per day averaged across the year, with summer well above that and winter below.

A 6.6kW system should therefore be producing somewhere in the region of 9,000–10,500 kWh annually. If yours is materially below that and the panels are clean and unshaded, something needs investigating — a failed panel, an inverter fault, or a string that has dropped offline.

Common bill surprises explained

“My bill went up in winter.” Expected. Perth solar production in June and July is roughly half the December peak, while heating load rises. A solar system flattens your annual cost; it does not flatten your monthly one.

“My feed-in credit is much smaller than I expected.” Almost always because most of your export falls in the low-rate window rather than the high-rate evening window — and your panels naturally generate most in the middle of the day, which is the low-rate period. This is a structural feature of DEBS, not a fault.

“My bill is near zero but not zero.” The daily supply charge. It is unavoidable while you are grid-connected.

“My neighbour has the same system and a lower bill.” Usually consumption timing, not system performance. A household home during the day self-consumes far more of its generation than one that is empty until 6pm.

What to do with what you find

High export, low self-consumption: move shiftable load into daylight — dishwasher, laundry, pool pump, hot water. Free, and often worth several hundred dollars a year.

High evening draw: model a battery. This is the single clearest indicator that storage will pay in a Perth home.

Generation below expectation: get the system checked. A single underperforming string can cost you meaningfully over a year and is often invisible without monitoring.

Everything looks right but the bill still feels high: check you are on the right tariff. Synergy offers several residential plans and the default is not always the best fit for a solar household.

A note on monitoring

Almost every modern inverter provides an app showing real-time and historical generation. If yours has never been set up, it is worth asking your installer to walk you through it — it turns a quarterly bill into a daily feedback loop and makes faults obvious within days rather than months.

Questions about your bill or system performance? Call 08 6255 5914.