Western Australia Solar Power System Grid Connection Rules & Process

The rules on inverter limits in Western Australia will depend on whether you’re in the Western Power (south-west WA) or Horizon Power (rest of WA) distribution area. These entities own and maintain their respective electricity networks. The following information is current as at August 2021.




Western Power

Single phase: 5 kW inverter limit, 5 kW export limit.

Three phase: 30 kW inverter limit, 30 kW export limit.

Western Power have advised that 30 kW three-phase limit is rarely granted, and 8-22 kW is the usual range granted.

Battery inverters do not count towards phase inverter limit.

Western Power website

Horizon Power

Single phase: 10 kW inverter limit, 5 kW export limit.

Three phase: 30 kW inverter limit, 15 kW export limit.

Horizon have advised that rural connections usually have much stricter requirements.

Battery inverters do not count towards phase inverter limit.

Horizon Power website

WA Solar Grid Connection Steps

The process for grid-connecting your solar power system in Western Australia will also depend on whether you’re in the Western Power or Horizon Power distribution area.

—- For The Western Power Region:

1. Electricity Retailer Application

Before installing a solar power system you’ll need to complete an application that you’ll lodge with your electricity retailer. Once that is processed, you’ll be given what’s called a retailer reference number.

2. Technical Approval From Western Power

The retailer reference number is to be used on Western Power’s Embedded Generation Application. Western Power will then advise if the proposed system gains technical approval, or in a case where it doesn’t, provide advice on what needs to be changed – for example, reducing the capacity of the system.

Once approved, a letter will be provided to you and your installer by Western Power stating as such. Your electricity retailer will also be informed, so meter programming/changeover can be arranged.

3. System installation

Before the system is installed, your installer must lodge an Preliminary Notice to Western power within 3 days of carrying out the work.

4. Meter Installed/Reprogrammed

Synergy will then work with Western Power to arrange meter installation/reprogramming on your behalf. Note that all metering related costs incurred will be charged on the bill following your installation.

After the system is installed and the meter changed or reprogrammed, the solar power system can be connected to the network by the installer. A Notice of Completion must be submitted to Western Power by the electrical contractor within 3 days of the system being connected.

5. Electricity Retailer Notified

Once Western Power has received final forms from your installer, it will notify your electricity retailer (Synergy), which will then make the necessary changes to your electricity account.

Further details can be found here.

—- Horizon Power Region

1. Contact Horizon Power

Contact Horizon Power to find out about the Renewable Energy Buyback Scheme (REBS), also known as a feed-in tariff and any changes in your consumption tariff.

2. Submit Connection Approval Form

Before you purchase a solar power system, you’ll need to complete a Renewable Energy System – Electricity System Connection Application form and submit it to Horizon Power. This must be approved by Horizon before proceeding any further.

Both you and your chosen installer will be notified in writing of approval status, which can take up to ten business days or longer.

3. System Installation

The system can be installed, but your installer will need to submit a preliminary notice three days prior to the installation and a completion notice within 3 days after the system is installed.

4. Meter Installation

After Horizon Power has received the notice of completion, it will either perform a meter changeover or reprogram your existing meter. The timeframe will vary depending on your location.

After this has been completed, your system can be switched on.

Further details can be found here.

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