New rules for WA solar and battery installations

If you’re thinking about installing solar or adding a battery in Western Australia, there’s an important new rule coming into effect from 1 May 2026 that you may start hearing about: Whole of Site Compliance.

This change only affects new or upgraded systems, but it’s worth understanding early so there are no surprises later.

What is Whole of Site Compliance?  

Whole of Site Compliance means that all solar and battery equipment on your property needs to work together as one coordinated system.

Instead of assessing each inverter on its own, electricity network operators now look at everything connected at your home — solar panels, batteries, and inverters combined — as a single “site”.

This helps keep WA’s electricity grid stable while allowing more households to install modern solar and battery systems.

When do the new rules apply?

These new regulations for solar and battery installations apply to: 

• Any solar or battery installation completed on or after 1 May 2026
• Any system upgrades after that date, such as adding a battery or replacing an inverter

They do not affect systems that were fully installed and commissioned before 1 May 2026, unless you choose to upgrade them later.

Why is the WA Government introducing this change? 

WA’s main grid—the South West Interconnected System (SWIS)— is the world’s largest isolated power system. With so much rooftop solar now installed, the grid needs smarter ways to manage energy flows, especially during low and minimum demand periods. The new rules allow for inverters with much larger capacities to be installed, which allows for larger systems, and more potential solar energy to be exported to the grid. While it's great to have more clean energy in the network, it does present some challenges for grid stability. These regulations will allow greater control of more solar systems to help prevent grid emergencies. 

Whole of Site Compliance allows:

• Safer integration of larger solar and battery systems
• Better protection against rare grid emergencies
• Future access to flexible export products and Virtual Power Plants (VPPs)

In short, it supports more clean energy without compromising reliability.

What does this mean for WA households?

From 1 May 2026, if you are installing a new or upgraded solar and/or battery system, you have two options to be compliant with the new regulations:

Option 1: Smart, connected system

Your entire solar and battery system can:

• be remotely visible to your electricity retailer (such as Synergy), 
• be temporarily controlled during rare grid emergencies, and
• join a Virtual Power Plant (VPP). 

These measures are already required to claim the WA Battery Rebate.

 From 1 May 2026, these measures apply for all new systems and upgrades in WA.

 Option 2: Fixed export limit  

Alternatively, if your site can’t meet those connectivity requirements, your system can still be installed; it just needs to be configured to a fixed export limit of 1.5 kW for the entire site.

Your solar still works for your home; however, you won't export more than 1.5 kW of solar from your system at any given time. This may impact your potential solar export and VPP revenue. 

What about existing solar systems?

You’re not affected unless you upgrade.

However, your system will need to comply with Whole of Site requirements if you:

• Add a battery
• Install an additional inverter
• Replace an inverter with a different model

 Are there any exemptions?  

Yes — the following situations are exempt or considered compliant:

• Like-for-like inverter replacements under warranty
• New systems set to a fixed 1.5 kW site export limit by customer choice. This fixed export option is being retained deliberately to provide flexibility for homes where reliable connectivity isn’t possible

 What does this mean for adding a battery?  

Whole of Site Compliance mainly affects the addition of a battery to an existing solar system. The age and configuration of your existing system, site requirements and your budget may all affect the path you choose.

You have some options to consider:

• Replace your solar inverter with a hybrid inverter; this may also be an opportunity to add more solar panels
• Replace your older panel array with a new, larger, more efficient array, and upgrade to a full solar + battery system (especially for systems 3+ years)
• Accept the site import limit of 1.5 kW
• Add an AC-coupled battery and inverter with an approved gateway device (Plico does not currently offer this option)

This is why many installers may now recommend simpler, integrated system designs when adding batteries - to ensure long-term compliance and reliability.

 The good news  

While these new requirements add some complexity to battery retrofits, they also provide benefits for the grid and for households, including:

• Allowing larger and more capable solar + battery systems to be installed,

• Giving customers a choice between smart exports or capped exports,

• No changes for existing systems, unless you upgrade, and

• Helping futureproof WA’s clean energy transition.

Most importantly, you can still install solar and batteries — these rules are about how systems connect, not whether you’re allowed to have one.

Thinking about solar or batteries in WA?  

If you’re planning a solar and/or battery installation or upgrade after 1 May 2026, it’s important to:

• Understand how your whole site will be assessed
• Choose equipment that’s compatible with Whole of Site Compliance 
• Work with an installer who designs for compliance from the start

If you’d like help navigating your options, we’re always happy to talk them through — no pressure, no jargon, just clear answers. 

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