Perth · Western Australia
Commercial solar in Perth generates more than anywhere else, and pays less for exports
Both halves of that sentence change how a system should be designed here. Perth businesses that get this right do very well. The ones that copy an east-coast design don't.
- Western Power
- Network operator
- 1,600 kWh/kW
- Annual yield
- STC Zone 3
- Federal discount zone
- No DEBS
- Buyback is for systems up to 5 kW
Rebates and exports
No WA rebate, and exports earn almost nothing, so your own load decides the size
There's no Western Australian rebate for commercial solar. The federal STC discount is the only up-front reduction, and it comes off the invoice rather than arriving as a payment later.
Exports are the weak point. The Distributed Energy Buyback Scheme only covers residential, not-for-profit and educational customers with systems of 5kW or less, so a commercial system gets nothing from it. Any payment for a business's exports comes down to its retail contract, and it is usually small or nothing. A Perth system earns its money by covering your own load, not by selling power back.
The practical effect is that a business running plant through the day gets a far better result in Perth than one that draws most of its power after 5pm.
Larger Perth sites now get more of that discount. From 1 October 2026, an eligible system from 100 kW to 1 MW can create STCs with a fixed 5-year deeming period, or REGO certificates instead, but not both for those years. The Clean Energy Regulator expects applications for these STCs to open in mid to late November 2026.
The commercial solar rebates page covers the STC discount and every state side by side.
Sources: Clean Energy Regulator: small-scale technology certificates (opens in a new tab); WA Government: energy buyback schemes (opens in a new tab); Clean Energy Regulator: mid-scale solar (opens in a new tab)
This works well in Perth
This needs a harder look
Connection
Connecting to Western Power
Perth sits on the South West Interconnected System, which Western Power operates on its own. Nothing about the connection process here matches the eastern states.
Above 30kVA of inverter capacity, a system leaves Western Power's basic embedded generator process and goes through a non-standard connection, with a technical assessment of the feeder your site sits on and application fees to match. Expect a longer approval.
Export limiting is common on larger commercial sites in constrained parts of the network. A system can still be worth building with exports capped at zero if the load profile suits it, but the payback maths changes and the proposal should show that.
Perth at a glance
- Network operator
- Western Power
- Grid
- South West Interconnected System
- STC zone
- Zone 3
- Annual yield
- 1,600 kWh per kW
- State rebate
- None
The yield advantage
What a Perth system is worth
The same 50 kW system, the same hardware, a similar installed price.
Perth
80,000 kWh
a year
Melbourne
62,500 kWh
a year
Difference
~$4,900
more value a year at 28c
Perth's yield advantage is real money. A 50kW system generating 80,000 kWh a year against Melbourne's 62,500 kWh is roughly $4,900 more value annually at a 28 cent grid rate, from identical hardware at a similar installed price.
That's why Perth payback periods tend to sit at the short end of the national range, as long as the self-consumption assumption holds. Run the numbers with export revenue set to zero. In Perth that's closer to reality than most proposals admit, and if the project still stacks up on self-consumption alone, it's a sound one.
The full method is on the cost and payback page, and the installation page covers what happens once a proposal is accepted.
By industry
Solar by industry in Perth
The network rules, the STC zone and the state incentive, worked through for one kind of site.
- Solar for cold storage in PerthYes, solar pays for most cold stores in Perth, and on the numbers it pays faster here than in any other capital.
- Solar for manufacturing in PerthFor a Perth manufacturer, commercial solar in 2026 pays back in roughly two to two and a half years on a weekday-shift site, and under two years on two…
- Solar for wineries in Western AustraliaDoes solar pay for a Western Australian winery? The best sun in the country, no income from exports, and Western Power's process above 30 kVA.
Guides
Guides to read before you get a quote
- 100kW solar for business: approval, rules and paybackRoof, network approval, the 1 October 2026 change and a payback table.
- Is a 30kW solar system big enough for your business?What 30kW makes, the roof it needs, and who it suits.
- How STCs work for business, and the 1MW changeThe upfront solar discount, how it's worked out, and what changed on 1 October 2026.
Questions
Perth questions
Is there a Western Australian rebate for commercial solar?
No. The federal STC discount is the only upfront reduction available to a Perth business, and it comes off the installer's invoice rather than arriving as a separate payment. Anyone offering a WA-specific commercial rebate is describing something that doesn't exist.
Source: Clean Energy Regulator: small-scale technology certificates (opens in a new tab)
Can a Perth business get the STC discount on a system over 100 kW?
Yes, if it's installed from 1 October 2026 and is no bigger than 1 MW. An eligible system from 100 kW to 1 MW can create STCs with a fixed 5-year deeming period, or REGO certificates instead, but not both for those years. The Clean Energy Regulator expects applications for these STCs to open in mid to late November 2026. A system installed before 1 October 2026 and above 100 kW sits outside the small-scale scheme.
Source: Clean Energy Regulator: mid-scale solar (opens in a new tab)
How much does commercial solar generate in Perth?
Around 1,600 kWh per kW of installed capacity a year, which is the best of any capital city on this site and roughly 28% more than Melbourne gets from the same system. A 50kW system in Perth produces about 80,000 kWh a year on a well-oriented roof.
Do businesses get paid for exports under DEBS?
No. The Distributed Energy Buyback Scheme covers residential, not-for-profit and educational customers with systems of 5kW or less. A commercial system isn't eligible, so any payment for its exports depends on your retail contract, and it's usually small or nothing. That's why a Perth commercial system is designed around covering your own daytime load, not around selling power back.
Source: WA Government: energy buyback schemes (opens in a new tab)
Do we need Western Power approval?
Yes, and above 30kVA of inverter capacity the application moves to a non-standard process with a technical assessment of the feeder your site connects to. Budget several weeks for it. On constrained parts of the network the approval can come back with an export limit attached.
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