What do the changes mean?
Western Power has published a WEM Procedure that introduces updated requirements for the installation of new or upgraded solar and battery systems in the SWIS. These requirements apply to “Standard Small User Facilities”, which are connections with a connection voltage below 1000 V and have an aggregate DER capacity of 30 kVA or less.
The change will permit more flexibility in the design of inverter energy systems up to an aggregate of 30 kVA under a standard connection (both single- and three-phase). This provides a pathway for larger systems (above the current limit of 5 kVA) to export greater quantities to the Western Power network and provide the opportunity for these customers to participate in virtual power plants (VPPs) or other flexible export products in the future.
In addition, The WEM Procedure will reinforce existing requirements for inverter energy systems to comply with AS/NZS 4777.2, including the use of “Australian Region B” at installation.
Lastly, the new WEM Procedure will require customers that wish to participate in an export product (e.g. Distributed Energy Buyback Scheme (DEBS)) to be capable of having their solar and battery systems remotely disconnected and reconnected. Electricity retailers will be responsible for nominating the technical solution for solar and battery installers to comply with.
For customers who do not wish, or cannot, maintain system connectivity requirements, installers must make sure that the site is export limited to 1.5kW. These sites are not required to comply with the remote disconnection requirement.
When working with Synergy customers, installers will be required to use Synergy Functionality Requirements and Interconnection Handbook. This includes commissioning systems using the CSIP-AUS standard. This is an open source communications protocol that has been developed in partnership with other states and territories to reduce costs for equipment manufacturers and ensure the rollout of this capability is standardised across Australia.
Why are we implementing these changes?
Western Australia’s South West Interconnected System (SWIS) is the biggest isolated grid in the world. The grid’s size and isolation, coupled with large amounts of exported solar, create a unique challenge for the Australian Energy Market Operator (AEMO) to maintain the stability of the power system.
We want to support as many people in Western Australia as possible to benefit from rooftop solar, and for those people to get the maximum benefit from each system. These changes make it possible for installers to continue connecting more and larger systems in the distribution network, and for electricity retailers to begin rolling out new products to take advantage of greater device functionality.
The changes are the first step to simplify requirements and legal arrangements for customers and installers. Once in place, we will commence other work with installers and device makers to support bigger systems and to create a streamlined connection process.
We heard you
We consulted industry and consumers on the proposed changes to make sure they deliver maximum customer benefit while remaining practical for installers.
As a result, we have delayed the start date for any changes from 1 February 2026 to 1 May 2026 to give installers more time to understand the changes before they come into effect. We have also made other changes to simplify wording for aggregate inverter capacity limits, and to timelines for a third-party aggregator framework.
We continue to welcome feedback from industry on these changes to inform refinement or additional requirements in the future. Please reach out by contacting smartersolar@deed.wa.gov.au
What does this mean for installers prior to 1 May 2026?
Nothing will change for industry until 1 May 2026, but we encourage installers to familiarise themselves with Western Power’s WEM Procedure prior to the commencement date.
Synergy is the retailer for most households in the southwest grid and will update training and technical materials for solar installers and retailers ahead of the 1 May 2026 commencement date. This will include technical guidance, adding new modules to its installer training portal, and offering in-person training sessions to help industry familiarise themselves with these new requirements.
Other retailers that have customers captured by Western Power’s WEM Procedure may have different solutions for complying with the WEM Procedure. Solar and battery installers will be required to work with the customer’s electricity retailer to comply with their preferred solution.
What would change in May 2026?
Installing new DER
Electricity retailers will be responsible for setting the commissioning processes for inverter energy systems. For Synergy customers, new or upgraded inverter energy systems will be commissioned in accordance with Synergy’s commissioning process, including establishing communications using CSIP-AUS, and must also continue to comply with all applicable standards and manufacturer commissioning requirements. More information can be found in Synergy’s DER Functionality Requirements.
Newly installed DER will only need to meet the base CSIP-AUS capabilities to be eligible for connection. It is important to note that compliance with CSIP-AUS is already required through the WA Government’s residential battery scheme, which includes specific battery storage capabilities. While these additional battery storage features are not mandatory for systems that are not seeking the WA rebate, they can provide extra value by enabling participation in a Virtual Power Plant (VPP).
The following installations are exempt from meeting criteria of Synergy’s Functional Requirements on an ongoing basis, or would be deemed to comply:
- Inverters replaced with a similar or exact replacement under warranty.
- Systems installed and commissioned before 1 May 2026.
- Systems that meet remote connect/disconnect functionality using an alternative method agreed with an electricity retailer, such as through SCADA.
- Systems designed and installed in accordance with Synergy’s DER Functionality Requirements and commissioned using CSIP-AUS, but where a customer chooses a fixed 1.5 kW export limit instead of another export arrangement. The fixed export option is being retained to provide choice, and for the small number of customer sites that struggle to maintain remote connect/disconnect functionality for emergency solar management because of physical site constraints.
Upgrading existing solar systems
The requirements outlined in Western Power’s WEM Procedure for Standard Small User Facilities will apply if an existing system is upgraded, such as by adding a home battery or an additional inverter.
For the small number of inverters or sites not capable of communicating and which cannot be updated through firmware, installers will be able to use gateways to meet site requirements. Gateways are available covering most of the existing inverter market. The WA Government previously published a fact sheet with information on some of the options available to customers upgrading these legacy systems.
Existing systems (no upgrade)
The new requirements only apply to inverter energy systems that are installed or upgraded on or after 1 May 2026. For systems installed before this date, installers must continue to comply with existing installation and connection requirements.
Frequently asked questions
View a range of frequently asked questions below.
Who is responsible for ensuring inverters maintain minimum functionality over time?
Show moreThere are no changes to who is responsible for maintaining device communications when new rules come into effect on 1 May 2026.
Installers will continue to be responsible for properly installing or upgrading solar and battery systems. Once installed, electricity retailers or aggregators will likely use a short post-installation period to test systems and remotely verify they comply with export limits and perform as expected. This is similar to what currently happens in South Australia.
Once commissioned, system owners will make sure that equipment maintains the minimum connectivity needed for systems to perform as expected. Often this will be a simple fix, like entering a new Wi-Fi password on an inverter.
There are no penalties if devices lose communication. Where communications are lost, devices will default to a lower static export limit. Once communications are restored, flexible export capability will automatically apply again, subject to the relevant product or operating arrangements.
Electricity retailers can monitor dynamic/flexible systems and may communicate to their customers to let them know their systems have lost connectivity for an extended period.
What information will I provide to existing or prospective customers?
Show moreMost customers are unlikely to be directly affected by the change, which is mainly to consolidate existing rules for installers and industry to prepare for future system improvements.
As with Synergy’s current deX platform for its Emergency Solar Management capability, we encourage installers to establish whether customers have an active internet connection before visiting a site.
We have published a dedicated customer information page on the WA Government website, which we welcome installers to download and provide to customers. It summarises what the changes mean in practice for new and upgraded systems.
I have installed systems under the WA residential battery scheme with inverters greater than 5 kVA, and these sites have a fixed 1.5 kW export limit. Would I need to revisit these sites?
Show moreNo. These systems already support the functionality that these changes will require. Customers with systems installed as part of the WA residential battery scheme will be able to opt in to flexible exports when their electricity retailer makes it available.
Will I be able to upgrade a customer’s current solar export arrangement?
Show moreYes. Installers may be able to bring sites up to the level of functionality needed for flexible exports.
Existing sites that already meet functionality requirements can be made flexible export-ready by agreement with a customer’s electricity retailer. For Synergy customers, this would simply mean enrolling the site using CSIP-AUS. Customers who wish to opt in to flexible exports or a VPP, but whose sites do not meet connectivity requirements, should speak to installers about any system changes needed.
What happens to commercial systems greater than 30 kVA?
Show moreThe changes do not affect installers or customers who plan to install solar or battery system bigger than 30 kVA. We are initially focussing on systems with a capacity of 30 kVA or less because this covers most systems currently being installed in the SWIS.
What is changing about how installers currently communicate with Western Power?
Show moreFor now, installers will still submit connection applications to Western Power. The WA Government is working with Western Power and Synergy on a streamlined connection process, so that installers only need to submit information once when on site.
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