Plug-in solar or rooftop solar: which suits a WA home?

Plug-in solar is not a cheaper version of rooftop solar. It is a much smaller product for people who cannot put panels on a roof. The ABC reports that more than 40 per cent of homes on the South West Interconnected System, WA’s main grid, already have solar panels. Under the draft rules those homes are out, so plug-in solar is aimed at the rest. Plug-in solar is not legal in WA yet, so the plug-in column below describes the draft only.

	Plug-in solar (draft rules)	Rooftop solar (today)
Size	Up to 2 kW of panels and an 800 VA inverter	6.6 kW of panels is a popular WA size
Typical price	Not known in WA. Overseas kits up to about $1,300 (ABC)	6.6 kW: $6,000 to $9,000 nationally (SolarQuotes)
Who installs	You plug it into a power point	Professional installer
Network paperwork	Install, then notify Western Power or Horizon Power	Full application before connection
Export payments	None for now	Synergy DEBS: 10c peak, 2c off-peak per kWh
Rebates	None announced	Federal STC discount on eligible systems
Moves with you	Yes	No
Legal now?	No, still a draft	Yes

How big and how expensive is a typical WA rooftop system?

SolarQuotes describes 6.6 kW as “a popular size in WA”. On price, its national cost guide (updated 12 October 2026) gives these “typical fully installed” ranges, based on what buyers reported paying:

System size	Typical installed cost (national, SolarQuotes)
3 kW	$3,500 to $5,500
5 kW	$5,000 to $7,500
6.6 kW	$6,000 to $9,000
10 kW	about $9,000 to $12,000

The page does not say clearly whether that table is before or after the federal STC rebate, and it is not WA-specific. SolarQuotes’ regional WA guide gives a rough out-of-pocket cost of “around $6,600” for a good-quality solar-only system after the federal rebate, using a 6.6 kW system for its estimates. Get local quotes for real Perth prices.

How much more power does rooftop solar make?

Several times more. As a rough estimate, NLR’s PVWatts model gave about 1,350 kWh a year for 0.8 kW of panels facing north at a 30 degree tilt in central Perth. Scaling that straight up to 6.6 kW suggests something like 11,000 kWh a year. That is my rough scaling, not a model run: it ignores the smaller inverter many WA rooftop systems use, the real roof angle and any shade, so treat it as an upper guide. The inputs behind the plug-in figures are on the Perth output page.

How does feed-in work for rooftop solar in WA?

Synergy customers with eligible rooftop systems are paid for exports under the Distributed Energy Buyback Scheme (DEBS). Synergy’s page lists:

Export time	Synergy DEBS rate
3pm to 9pm	10 cents per kWh
Before 3pm or after 9pm	2 cents per kWh

Synergy’s page gives no effective date for these two rates (checked 5 November 2026). Energy Policy WA’s page gives the same rates for Synergy customers, as of 1 July 2024, and says DEBS rates “are reviewed and adjusted each year”. For most Horizon Power customers it lists 10 cents from 3pm to 9pm and 3 cents at other times.

Some key conditions, from those two pages:

• Energy Policy WA says a system must have a generating capacity “between 500W and 5kW” to be eligible for DEBS.
• Synergy says new and upgraded DEBS systems with an inverter of 5 kW or less must be able to be turned off remotely in an emergency solar management event, and larger systems face export limits.
• Older customers on the Renewable Energy Buyback Scheme (REBS) can stay on it at 7.1350 cents per kWh, but changes such as a bigger system, a battery or a new inverter mean moving to DEBS.

The pattern matters. Most rooftop solar exports happen in the middle of the day, when the rate is 2 cents. My reading is that this is why WA rooftop owners, like plug-in owners, get the most value from using their solar themselves.

Why does plug-in solar get no feed-in payment?

The draft proposal leaves it out. The WA Government FAQ says paying for exported electricity is not part of the proposal, because reprogramming or upgrading a meter for export payments would likely cost consumers more than it returns. The focus is self-consumption. A plug-in kit only saves you money on power you use at the moment it is made, at your full tariff, which is 33.2621 cents per kWh on Synergy’s Home Plan (A1) from 1 July 2026. See cost and savings.

Can I have plug-in solar and rooftop solar together?

No, not under the draft. Section 1 of the draft standard says: “Only one plug-in generator shall be used per household, and a plug-in generator must not be used at sites with an existing fixed installation (e.g. traditional rooftop solar).”

The draft defines a household as a dwelling with its own electricity supply and switchboard. In a strata block or apartment building, each dwelling with its own switchboard counts as a separate household. My reading is that a common-property rooftop system on a strata building may or may not count as an “existing fixed installation” for each apartment. The draft does not say, so that is an open question for the consultation. See strata and balcony solar.

How do the approvals differ?

The FAQ says existing rules were written for larger, professionally installed rooftop systems, which go through a full application. Plug-in systems would instead follow a simpler “install, then notify” process. You would plug in a certified kit, then tell Western Power or Horizon Power using a simple form. The consultation paper says plug-in kits would be certified as ordinary appliances and, “unlike traditional rooftop solar inverters”, makers would not submit them to the Clean Energy Council for approval.

Which one should I choose?

If you own a house with a sunny roof and no solar yet, rooftop solar is legal today, makes far more power and earns a feed-in credit. Plug-in solar makes most sense where rooftop solar is not an option: you rent, you live in an apartment with your own switchboard, or your roof does not suit panels. More on that for renters and apartments.

What if I get rooftop solar later?

Under the draft, you would have to stop using the plug-in kit at that address. Because it is portable, you could take it to a new home that has no fixed solar system, as long as that home has no other plug-in generator.