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

If you export solar electricity to the grid in Perth, Synergy credits your bill under the Distributed Energy Buyback Scheme (DEBS). The scheme has two rates that apply at different times of day — and understanding them changes how you think about when to use and when to export your solar power.

What is DEBS?

DEBS (Distributed Energy Buyback Scheme) is the WA state government's solar export credit scheme. It replaced the Renewable Energy Buyback Scheme (REBS) and the Synergy Net System Benefit Tariff (NSBT) from August 2020.

Under DEBS, Synergy pays you a credit on your electricity bill for every kilowatt-hour you export to the grid. The credit appears on your quarterly bill as a negative line item (reducing your bill).

Current DEBS rates

DEBS has two rate periods:

Super Off-Peak rate (9am–3pm): 10c/kWh This is when solar panels produce the most power in Perth — midday generation falls exactly in the Super Off-Peak window. Export during these hours earns the highest rate.

Off-Peak rate (all other times): 2c/kWh Before 9am, between 3pm and 9pm (the Synergy peak period when your import costs most), and overnight. Export during these hours earns only 2c/kWh.

Midday Saver interaction: If you're on the Midday Saver tariff, the 9am–3pm window is when you pay only 8.8511c/kWh to import. Exporting at 10c in that window and importing at 8.8511c is a slight net positive for each kWh cycled through the grid.

Why the rate split?

The 10c/2c structure is deliberately designed to signal value to the grid. Solar panels across WA generate most when the sun is overhead — coincidentally, when air conditioning demand is also high in Perth's summers. The 10c Super Off-Peak rate compensates solar owners for providing power precisely when the grid needs it.

The 2c Off-Peak rate is low intentionally. At 3pm–9pm (the Synergy peak period), solar panels are producing little or nothing — Synergy is buying expensive peaking power from gas generators. Your battery discharging into the grid during peak hours would theoretically help, but DEBS discourages this at 2c (below cost for most battery systems), directing battery owners to use stored power for their own consumption instead.

How 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 (in dollars, as a negative)

The bill doesn't usually break down exported kWh by time period — you see a total export volume and a total DEBS credit. If your export credit exceeds your import charges, you receive a net credit (Synergy owes you money), which is either paid by direct deposit or carried forward to the next quarter depending on your payment setup.

Monitoring detail: Your inverter monitoring app (Sungrow iSolarCloud, SolarEdge, Goodwe SEMS, etc.) typically shows daily and hourly export data, allowing you to see how much of your export fell in the 10c vs 2c windows.

When DEBS was introduced vs older schemes

Perth solar owners who installed before 2010 may be on the old REBS scheme (7c flat rate) or even the pre-REBS residential scheme. If you're on an older scheme, you're almost certainly getting a worse deal than DEBS if your export volume is weighted towards midday hours.

Switching to DEBS: You can voluntarily switch from REBS to DEBS by contacting Synergy. Once you switch, you cannot return to REBS. Before switching, calculate whether your export pattern favours DEBS (midday-heavy export) or REBS (flat 7c across all hours). Generally, systems without batteries that export heavily between 9am–3pm benefit from switching to DEBS. Systems that export more in early morning or late afternoon (east-west facing) should compare carefully.

How to maximise your DEBS export credit

Export more between 9am and 3pm: This means using your large loads (dishwasher, washing machine, hot water top-up) outside of peak solar hours, not during 9am–3pm when your export rate is highest.

Avoid exporting in the 3pm–9pm window: If you have a battery, charge it from solar during 9am–3pm rather than exporting. Use the stored energy in the 3pm–9pm window instead of exporting (2c) when you could displace expensive import (33.26c on A1 or peak rate on Midday Saver).

Self-consumption first, then export: Your solar saved at the A1 import rate (33.26c/kWh) is worth more than exporting at 10c. Prioritise running appliances from solar over exporting.

DEBS and the WA Battery Incentive rebate

The WA Battery Incentive ($130/kWh, max $1,300) is a rebate on battery purchase — separate from DEBS. Having a battery doesn't change your DEBS rate or eligibility. The incentive is a one-time purchase rebate from Synergy, not an ongoing export tariff.

Important: Tesla Powerwall 3 is NOT on Synergy's Solar Suitability List and is ineligible for the WA Battery Incentive. This does not affect DEBS eligibility — you can receive DEBS credits regardless of which battery you have.

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

Upgrading your solar system (adding panels, replacing the inverter) typically requires notifying Synergy. Your DEBS eligibility continues — DEBS applies to your ongoing export regardless of system changes, as long as your system remains connected and registered.

If you add a battery, DEBS applies to any net export (generation minus both consumption and battery charging). Battery export to the grid during the 2c Off-Peak window is generally not encouraged by the tariff structure.

DEBS is straightforward once you understand the two-rate structure: 10c when the sun is highest (9am–3pm), 2c at all other times. Self-consume first, export the surplus, and use a battery to shift generation from the 10c export window to the 33.26c import-avoidance opportunity in the evening.