What the rating counts
Batteries became eligible under the Small-scale Renewable Energy Scheme on 1 July 2025, and the CER's battery inspection program started a fortnight later, on 15 July. To 8 June 2026 it had assessed 2,642 systems: 970 adequate, 1,650 substandard and 22 unsafe. That is the 62.45 per cent now in circulation.
The regulator defines the middle rating precisely. Substandard systems "do not meet one or more clauses in Australian Standards or industry guidelines but are safe to remain in operation". One clause, anywhere on the checklist, rates the whole system. That is a reasonable way to run an inspection program and a poor way to read one, because it means the system rate and the defect rate are different measurements of different things.
The item-level figures show how far apart. Across 227,945 assessed checklist items, 213,096 complied, 11,913 drew a recommendation for improvement, 2,910 required rectification and 26 were unsafe. So 93.49 per cent of everything inspectors looked at was compliant, and 1.28 per cent needed fixing. Those 2,910 rectifications are spread across 1,650 substandard systems, which is fewer than two per system.
0.83%
of inspected battery systems were rated unsafe, against 62.45 per cent rated substandard
The rate that did not move
If installation quality had genuinely collapsed in a new product category, the unsafe rating should carry some of it. It does not. Batteries were rated unsafe in 22 of 2,642 systems, 0.83 per cent, and at item level in 26 of 227,945, which is around one item in nine thousand.
The rooftop solar program is the closest available control, run by the same regulator against the same three ratings. In its 2024-25 program the CER inspected 2,586 solar systems, of which 2,532 were a random sample. Of those, 223 systems installed in 2024 were rated substandard (18.6 per cent) and 5 were rated unsafe (0.4 per cent); for systems installed in 2023 the figures were 262 substandard (19.6 per cent) and 12 unsafe (0.8 per cent). The battery unsafe rate sits inside that band. Over the life of the solar program to 30 June 2025, the unsafe share is higher still: 300 of 11,281 inspections in New South Wales and 332 of 12,129 in Queensland, both near 2.7 per cent.
So the two categories differ by a factor of more than three on substandard and by nothing meaningful on unsafe. Whatever is driving the battery figure is being caught by the rating that explicitly means "safe to remain in operation".
Where the flagged items sit
The category breakdown says what it is. Labelling is compliant on 76.22 per cent of assessed items, which makes it the weakest category by a wide margin, but most of that gap is recommendations for improvement (20.76 per cent) rather than rectifications (3.02 per cent). Mechanical protection carries the highest rectification rate at 3.99 per cent, with overcurrent protection next at 1.83.
One caution on reading that ranking as a ranking of causes: these are rates within each category, and the CER does not publish how many items each category contributes. A category can carry the highest rate and still account for few rectifications overall. What the table does support is where the unsafe items are, and they are narrow: wiring (0.03 per cent of its items), installation requirement (0.02) and isolation (0.01). No other category recorded an unsafe item at all.
| Checklist category | Complies | Recommendation | Rectification | Unsafe |
|---|---|---|---|---|
| Labelling | 76.22% | 20.76% | 3.02% | 0.00% |
| Protection from fire | 94.95% | 3.83% | 1.22% | 0.00% |
| Mechanical protection | 96.01% | 0.00% | 3.99% | 0.00% |
| Wiring | 97.50% | 1.60% | 0.87% | 0.03% |
| Overcurrent protection | 98.05% | 0.12% | 1.83% | 0.00% |
| Isolation | 98.11% | 1.52% | 0.36% | 0.01% |
| Documentation | 98.70% | 1.27% | 0.03% | 0.00% |
| Restricted locations | 98.95% | 0.81% | 0.24% | 0.00% |
| Installation requirement | 99.56% | 0.40% | 0.02% | 0.02% |
Clean Energy Regulator, battery inspection results report, checklist criteria results by category, covering 1 July 2025 to 8 June 2026. Percentages are of assessed items within each category, not of all items. The CER does not publish the item count per category, so these rates cannot be converted into shares of total rectifications.
The spread the national figure hides
The per-state counts are the part of this dataset I would look at first, and they are not what a single national rate suggests. Queensland rated 437 of 565 inspected systems substandard, 77.3 per cent. The ACT rated 35 of 93, or 37.6 per cent. That is a spread of nearly forty points inside one national scheme with one checklist.
| State or territory | Adequate | Substandard | Unsafe | Inspections | Substandard rate |
|---|---|---|---|---|---|
| Queensland | 123 | 437 | 5 | 565 | 77.3% |
| Northern Territory | 2 | 6 | 0 | 8 | 75.0% |
| Western Australia | 113 | 195 | 2 | 310 | 62.9% |
| South Australia | 150 | 228 | 3 | 381 | 59.8% |
| New South Wales | 247 | 367 | 7 | 621 | 59.1% |
| Victoria | 279 | 381 | 3 | 663 | 57.5% |
| ACT | 56 | 35 | 2 | 93 | 37.6% |
| Tasmania | 0 | 1 | 0 | 1 | 100.0% |
Counts from the CER's published per-state CSV; the substandard rate is calculated from those counts and is not published by the regulator. Tasmania (1 inspection) and the Northern Territory (8) carry denominators too small to read as rates, and are shown here only for completeness.
What I am not willing to conclude
Four limits, and the first is the one that matters most. The CER documents the sampling basis of its solar program as a "statistically significant random sampling method", with additional risk-based inspections counted separately (2,532 random of 2,586 in 2024-25). It does not publish the equivalent basis for the battery program. Until it does, the battery rate cannot be treated as an estimate of the installed population, and extrapolations that scale it to national totals do not follow from what is published.
Second, the solar comparison has a definitional break in it, and it falls where the solar series improves. The CER states that it refined its checklist so that installations "previously rated as substandard based on broad general clauses or at an individual inspector's discretion can now be assessed more precisely". Part of solar's improvement is a change in how the rating is applied. The update also carries two substandard series that do not agree: a summary series of 24.6 per cent for 2022, 22.6 for 2023 and 18.7 for 2024, and the random-sample series by install year quoted above. The report does not reconcile them.
Third, the battery figures are cumulative across the program's first eleven months rather than a period rate, so they cannot yet show a trend. Two readings exist, 1,278 inspections to April 2026 and 2,642 to 8 June 2026, and the second contains the first.
Fourth, this is a new checklist applied to a new product class by inspectors and installers both working to it for the first time. Solar's own record is the useful precedent here rather than a rebuke: on the CER's summary series it sat at 24.6 per cent substandard in 2022, and its life-of-program unsafe share in the two largest states is near 2.7 per cent, well above where batteries are now.
Why this is a fleet property
The reason to carry this in a dataset rather than only in a headline is that installation quality is a property of the installed fleet, and we have been treating it as uniform. A rate that runs from 37.6 per cent to 77.3 per cent across states is not uniform, and it is now measured. Any assumption about how a battery fleet performs or degrades that is applied evenly across jurisdictions is resting on something the regulator has started to publish and we have not been reading.
Three things I will look for in the next release. Whether the rate moves once successive periods can be separated from the cumulative total. Whether the CER publishes the battery program's sampling basis. And whether the state spread narrows, because if it holds across a larger sample it is telling us something about jurisdictions rather than about batteries.