Western Australia has one of the highest rates of rooftop solar in the world, and on mild, sunny days that solar can supply more than the grid can safely absorb. Emergency solar management (ESM) is the safety net for those rare moments. This article explains what ESM is, who can use it, what the rules that started on 1 May 2026 mean for a new or upgraded system in Perth, and how batteries and rebates fit in.
This article is part of our guide to Western Power Solar Rules: Connection, Export Limits and Approvals in WA.
Install before 31 December 2026 to lock in this year's rebates.
From 1 January 2027 the federal battery rebate drops by about 16% (STC factor 6.8 → 5.7) and the solar panel rebate by about 20% (deeming period 5 → 4 years). It falls again in July 2027. The WA $1,300 rebate is limited to 100,000 households and is paid until the allocation runs out. Installation slots before Christmas fill fast, so lock in a date now.
ESM lets rooftop solar systems be turned down or off remotely in a power system emergency. The Australian Energy Market Operator (AEMO) decides when a response is needed, and your electricity retailer (Synergy in Perth) sends the signal to the systems. Western Power sets the technical requirements. It is a last-resort tool for rare events, not routine control, and your home keeps its grid supply while your solar is turned down.
Perth and the South West are on the South West Interconnected System (SWIS), a large grid that is not connected to the eastern states, so it cannot send surplus power elsewhere. On low-demand days in spring and autumn, rooftop solar can supply most of the demand, leaving too little conventional generation running to keep the grid stable. Grid-scale batteries now soak up some of that midday solar, but ESM remains the backstop.
The WA Government introduced ESM on 14 February 2022 for new and upgraded systems with inverters of 5 kW or less. Larger systems were export-limited instead.
From 1 May 2026, new and upgraded rooftop solar and battery systems on the SWIS changed in three ways:
The rules do not specifically require the CSIP-AUS communications standard, although the WA Government encourages retailers to use it. How your system is connected for ESM (for example through the inverter maker's cloud, which needs a home internet connection) depends on the equipment; your installer will tell you what yours needs.
A system you installed earlier keeps the rules that applied when it was installed unless you upgrade it.
Either way, the most valuable thing you can do with solar is use it yourself. On Synergy's standard Home Plan (A1) grid power costs about 33 cents per kWh (as at 1 July 2026), far more than any export rate.
A battery stores midday solar, which would otherwise earn 2 cents, for use in the evening. Batteries installed now come under the same 1 May 2026 rules, and two rebates cut their cost:
Example 1: new 6.6 kW solar system, no battery, with ESM capability
Example 2: adding a 10 kWh battery to an existing 5 kW system
Example 3: new system with a 1.5 kW export limit
These examples are illustrative. Actual results depend on system size, your usage, export patterns and tariffs.
Q: What is ESM for?
A: Keeping the SWIS stable when rooftop solar supply is so high, and demand so low, that the grid is at risk.
Q: Can my solar be switched off whenever the retailer wants?
A: No. It is used when AEMO needs a response to prevent a power system emergency. It is a last resort, not routine control.
Q: Is my existing system affected?
A: Not unless you upgrade it, for example by adding a battery or replacing the inverter.
Q: What if I don't want remote switching?
A: You can have a 1.5 kW export limit instead, but those exports are not paid under DEBS.
Q: How does a battery help?
A: It stores surplus solar for your own use in the evening, so less of your solar depends on exports at all.
Q: Where can I read the official rules?
A: On the WA Government's Energy Policy WA pages and Western Power's website, linked below.
Your installer applies to Western Power, sets the inverter to the right standard, sets up the ESM connection or export limit, and claims the federal STC discount on your behalf. For the WA battery rebate the installer must also be on the Plenti Vendor Directory; Sun Direct Power is an approved Plenti vendor.
Emergency solar management is what lets WA keep adding rooftop solar safely. For a new or upgraded system it means choosing remote ESM capability (normally the better option, as it keeps your DEBS payments) or a 1.5 kW export limit. A battery makes you less dependent on exports, and the federal and WA rebates make one cheaper, until the federal rebate steps down on 1 January 2027.
General information only, not financial or electrical advice. Rules, rebates and tariffs change; check the current details with the official sources below.
Sun Direct Power installs solar and batteries across Perth and WA, and we are an approved Plenti vendor for the WA Residential Battery Scheme. On every package the rebates are taken off the quote, not paid back later:
Systems start from $7,114 after rebates. See all our packages or get a fixed quote for your home.
Facts checked 27 October 2026.
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