New WA solar rules from 1 May 2026: what Perth homeowners need to know

From 1 May 2026, new and upgraded rooftop solar and battery systems in WA’s South West Interconnected System (SWIS), including Perth, must meet updated connection and commissioning requirements. The practical change is simple: you can install larger total inverter capacity (up to 30kVA), but your system must either support Emergency Solar Management (remote disconnect and reconnect) or be capped to a fixed 1.5kW export limit. Inverters must also be commissioned to AS/NZS4777.2:2020 with the correct “Australia Region B” settings.

Please note: This is a developing scenerio subject to Western Power’s technical rules.

Source: WA Government – New requirements for solar and batteries: information for consumers

This matters if you are installing solar for the first time, adding a battery, upgrading an inverter, or expanding your existing PV system after 1 May 2026.

Synergy export limit and how it works

What changes on 1 May 2026 in WA for Solar?

1) Up to 30kVA total inverter capacity allowed on standard connections

WA is allowing households and small businesses on standard connection services to install up to 30kVA of total inverter capacity. This is aggregate, meaning it includes solar inverter capacity, battery inverter capacity, and any other inverter-based generation on site. WA’s guidance also references that this aligns to 15kW installed generation capacity for single-phase sites.

In plain English: more flexibility for larger solar and battery systems, as long as the system is commissioned correctly.

2) Emergency Solar Management is required for 5kW and under, unless you choose a fixed 1.5kW export limit

All new and upgraded systems from 1 May 2026 must either:

be capable of remote disconnect and reconnect (Emergency Solar Management), or
be set to a fixed export limit of 1.5kW.

Emergency Solar Management is designed to protect grid stability during rare low-demand events. It curtails solar export or generation when needed, rather than cutting power to your home.

3) Commissioning must meet AS/NZS4777.2:2020

Inverters must comply with AS/NZS4777.2:2020 and be commissioned with the correct grid settings, including “Australia Region B”. This is a commissioning and compliance requirement, not a marketing feature.

Does this affect existing solar systems in Perth?

Not unless you upgrade.

If you already have solar, these rules apply when you install or upgrade a system on or after 1 May 2026. Common upgrades that trigger new compliance include:

adding a battery
increasing PV size
replacing or adding inverters
major system alterations that require re-approval

If you are planning a battery add-on to an older system, treat it as a full compliance project, not a simple bolt-on.

The 1.5kW export limit option: when it makes sense

A fixed export limit caps how much surplus solar can be exported to the grid. Your home still uses solar first, and any surplus above the export limit is clipped unless stored in a battery or used by loads like EV charging.

This pathway can make sense when:

site connectivity makes remote management difficult, or
you are prioritising self-consumption (especially with a battery), or
you want to reduce exported energy because export is less valuable than avoiding imports.

Important trade-off: the WA guidance notes export-limited systems may not be eligible for DEBS buyback payments.

What this means for Perth solar and battery design

Larger systems are now about smart self-consumption, not just export

With more headroom for inverter capacity, the best outcomes in Perth will come from systems designed around:

daytime household loads (air con, pool pumps, appliances)
battery charging windows
EV charging integration
export control to match network limits and retailer requirements

Batteries become more valuable when exports are limited

If exports are capped (either by network limits or by choosing the 1.5kW pathway), a battery helps capture surplus solar and shift it into evening and morning usage when tariffs are higher and solar is low.

For most Perth homes, battery value is highest when it reduces grid imports between late afternoon and bedtime, and when it soaks up midday surplus that would otherwise be exported or clipped.

How Australis Solar ensures your install is compliant from 1 May 2026

For Perth installs and upgrades after 1 May 2026, our process focuses on compliance first and performance second:

Confirm whether your project is a new install or an upgrade that triggers new requirements
Design within the 30kVA aggregate inverter capacity limits where applicable
Confirm the correct pathway: Emergency Solar Management enabled, or fixed 1.5kW export limit
Commission the inverter to AS/NZS4777.2:2020 with Australia Region B settings
Align documentation and commissioning steps with Synergy and Western Power connection requirements

This avoids approval delays and ensures your system operates as expected from day one.

FAQs

Is Emergency Solar Management the same as backup power?

No. Emergency Solar Management is a grid stability requirement that allows remote curtailment of solar generation or export. Backup power is optional and requires the correct hardware (Sigenergy Gateway, or Fronius GEN24 Plus + Backup Controller).

If I add a battery after 1 May 2026, do I need to comply even if my old solar did not?

Yes. A battery installation is an upgrade and must meet the current requirements at the time of installation.

Will these rules apply in Perth?

Yes. Perth sits within the SWIS, which is the system referenced in the WA requirements.

Talk to an Australis Solar specialist about your upgrade plan

If you are planning solar or a battery upgrade for May 2026 onwards, the key is getting the design and commissioning pathway right upfront. A compliant, well-commissioned system avoids approval headaches and delivers better self-consumption, lower bills, and easier future upgrades.