DEBS explained: how Perth's solar feed-in tariff actually works

DEBS (the Distributed Energy Buyback Scheme) is what Synergy pays Perth solar owners for electricity exported to the grid. It has two rates that swap depending on the time of day: 2c/kWh most of the day, and a higher 10c/kWh between 3pm and 9pm. That's the opposite of when your panels are producing the most, so the scheme is really a nudge to shift consumption toward midday and hold your export back for the evening, ideally with a battery.

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What is DEBS?

DEBS is the WA state government's solar export credit scheme, run through Synergy. The government launched it on 31 August 2020, and it replaced the Renewable Energy Buyback Scheme (REBS) for new and upgraded systems from 8 September 2020, once the window for late REBS applications closed.

Synergy credits your bill for every kilowatt-hour you export to the grid. The credit shows up on your quarterly bill as a negative line item, reducing what you owe.

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What are the current DEBS rates?

DEBS runs on two rate windows:

Peak export rate: 3pm-9pm, 10c/kWh This is the Synergy peak import period too, when grid demand is highest and gas peaking plants are running. DEBS pays the higher rate here because exported solar (from a battery, since panels alone are producing little by 3pm) genuinely displaces that expensive peaking power.

Off-peak export rate: all other hours, 2c/kWh That includes the 9am-3pm window when your panels are producing the most. Midday is when WA's grid is typically flush with solar from every rooftop on the network, so there's little value in paying a premium for more of it. Export during these hours earns only 2c/kWh.

This catches a lot of Perth solar owners out. It's easy to assume the best export rate lines up with peak generation. It doesn't: the best export rate is in the evening, when your panels have mostly stopped producing and a battery is the only way to capture it.

Daily cap: 50kWh. DEBS credits only the first 50kWh of combined peak and off-peak export each day. Anything past that earns nothing at all. Most Perth households never come close. A large array paired with a battery discharging hard into the evening is the setup that can.

Midday Saver interaction: If you're on the Midday Saver tariff, 9am-3pm is also your cheapest import window, at 8.8520c/kWh. Exporting at 2c and buying back at 8.8520c in that window is a net loss per kWh cycled through the grid, not a gain. There's no arbitrage to chase here: the sensible move at midday is to self-consume or charge a battery, not export.

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Why is the rate split like this?

The 2c/10c structure signals value to the grid, not to your rooftop. Perth's rooftop solar collectively floods the grid around midday, so DEBS pays little for more of it then. By 3pm-9pm, that same rooftop solar has mostly switched off just as Synergy's own peak demand (evening cooking, air conditioning, lighting) is climbing, and Synergy is buying expensive power from gas generators to cover it.

Paying 10c for export in that window rewards whoever can actually deliver power then, which in practice means a battery discharging stored midday solar rather than a panel array producing nothing after sunset.

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How do DEBS credits appear on your Synergy bill?

Your quarterly Synergy bill shows:

• Total kWh consumed from the grid
• Total kWh exported to the grid
• DEBS credit amount, shown as a negative dollar figure

The bill typically shows a total export volume and a total DEBS credit rather than a breakdown by time window. If your export credit exceeds your import charges, you get a net credit, either paid out by direct deposit or carried forward to your next bill, depending on your account setup.

Checking the split yourself: Your inverter monitoring app (Sungrow iSolarCloud, SolarEdge, Goodwe SEMS, and similar) usually shows hourly export data, so you can see how much of your export actually falls in the 10c window versus the 2c window.

Working out your own credit: take your total peak export (kWh sent out between 3pm and 9pm) and multiply it by 10c. Take your total off-peak export and multiply it by 2c. Add the two together and you have the credit for the period.

That shortcut assumes you stay under the 50kWh daily cap every day, which almost every household does. If you have a large array and some days clear 50kWh of export, work those days out individually first, since the export above the cap earns nothing and multiplying the period total would overstate your credit.

Export volumes swing a lot with system size, roof direction and season, so run your own kWh through it rather than borrowing someone else's figure.

If no export credit line appears at all, your smart meter upgrade or scheme registration may still be working its way through. Give it another billing period, then call Synergy on 13 13 53 to check.

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How does DEBS compare to the older REBS scheme?

Some Perth solar owners whose REBS application reached Synergy by 7 September 2020 are still on REBS, a flat 7.135c/kWh regardless of time of day, rather than DEBS. Whether REBS or DEBS suits you better depends on when your system exports.

Switching from REBS to DEBS is one-way. Once you switch, you cannot go back. Before switching, weigh up your export pattern:

1. Systems exporting heavily between 3pm and 9pm (batteries discharging on a timer, or east/west-facing arrays with a late-afternoon skew) generally do better on DEBS, since that's the 10c window.
2. Systems without a battery that export mostly at midday may find DEBS pays worse per kWh at that time (2c) than REBS' flat 7.135c, even though DEBS is better in the evening.
3. Run the comparison against your actual export profile, not an average, since the two schemes reward different hours.

For the full comparison, see which buyback scheme are you on.

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How do you get the most out of DEBS?

Self-consume during 9am-3pm. Solar you use directly, instead of exporting, is worth the A1 import rate you avoid buying, currently 33.26c/kWh. That's well ahead of the 2c you'd get for exporting the same kWh at midday. Run the dishwasher, washing machine, or a hot water top-up during the day rather than the evening.

Charge a battery from midday solar, not the grid. If you have a battery, filling it with your own 9am-3pm generation costs nothing and sets you up to use or export that energy later, when it's worth more.

Discharge or export in the 3pm-9pm window. This is where DEBS actually pays well (10c), and it's also when grid import is most expensive if you're not exporting. Using stored solar to cover your own evening load, rather than buying at peak rates, is usually worth more than exporting it. For the arbitrage math on Midday Saver specifically, see Midday Saver and battery: using off-peak charging to cut your bill.

Self-consumption beats export in nearly every case. For the full hour-by-hour breakdown, see self-consume vs export: solar strategy for Perth households.

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Does having a battery change your DEBS rate?

No. The WA Battery Incentive rebate ($130/kWh, capped at $1,300) is a one-off payment toward buying a battery, separate from DEBS. Having a battery doesn't change your export rate or your DEBS eligibility either way.

Battery model eligibility for the rebate itself varies and changes over time: confirm the inverter it pairs with is SSL-approved for DER Storage on Synergy's Supported Solutions List, and that it carries CEC approval, before assuming it qualifies, rather than relying on older reviews or marketing material.

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What happens to DEBS if you upgrade or expand your system?

This is the trap in the scheme, so it's worth being precise. DEBS only pays systems with a solar generating capacity of 5kW or less, measured at the inverter and counted across your whole system (on a three-phase home the cap is a total, not a per-phase allowance). The standard Perth install of 6.6kW of panels on a 5kVA inverter is officially deemed a 5kW generating capacity, so it qualifies.

Adding panels while your inverter stays at 5kW or under keeps you eligible. Topping up a 4kW array to the full 6.6kW on the same 5kVA inverter changes nothing about your DEBS payments.

An upgrade that takes your inverter capacity past 5kW is a different story: the feed-in payment doesn't shrink, it stops. Swap a 5kW inverter for an 8kW hybrid, or add a second inverter that pushes the total over, and Synergy no longer credits your export at all. The bigger system still connects to the grid (Western Power just applies an export limit at the connection point), but every kWh you send out earns nothing, and having the bigger inverter export-limited back to 5kW does not restore eligibility. The rule looks at the capacity you have installed, not what you're allowed to push out.

The technical-requirements changes that took effect on 1 May 2026 didn't soften this. They made connecting bigger systems easier (a standard connection now allows up to 30kVA of aggregate inverter capacity), but the 5kW payment cap stayed exactly where it was.

None of that automatically makes a bigger system a mistake. For plenty of households the extra self-consumption is worth more than the DEBS credit ever was. But the export income line in your upgrade maths should read zero once the inverter passes 5kW, so run the numbers on self-consumption alone before you commit, and tell your installer DEBS matters to you before they size a replacement inverter. For the mechanics of expanding, see adding more solar panels to an existing system in Perth.

Adding a battery changes none of this: DEBS caps solar generating capacity, not battery size. DEBS applies to net export (generation minus your own consumption and battery charging), and exporting from a battery during the 2c off-peak window rarely makes sense financially, so most battery owners aim to hold that stored energy for the 10c evening window or their own use instead.

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DEBS pays 10c/kWh from 3pm to 9pm and 2c/kWh the rest of the day, including the midday hours when your panels produce the most. Self-consume first, use a battery to hold midday solar for the evening, and check the 3pm-9pm window before you assume exporting is your best move. For how this compares against Synergy's other Perth tariffs, see your Synergy bill explained.