Australian small-scale battery registrations fell in each of the three months following the certificate changes that commenced on 1 May 2026. Registered capacity was 2.43 GWh in April, 1.51 GWh in May and 1.07 GWh in June. The April figure was a record, set by demand brought forward ahead of the change.
Current-guidance boundary: This article records an August 2026 interpretation of provisional registration data. It does not establish final installation volumes or current scheme settings. Current Clean Energy Regulator guidance and site-specific requirements control any quote or system design.
Those numbers have been reported widely as a collapse. The market analyst SunWiz, whose dataset the monthly figures are drawn from, published an assessment on 6 August 2026 arguing that the reported decline overstates what has occurred. Two mechanisms account for the gap between the published figures and the underlying position.
Recent months are incomplete when first published
The first mechanism is administrative. The Clean Energy Regulator requires that certificates be created in the REC Registry within twelve months of the installation date. An installation completed in June may therefore have its certificates created in June, in December, or in the following May.
The consequence is that any recent month is undercounted at first publication and fills in as certificates are created. A figure published for the month just gone is a provisional draft, not a final count, and it will be revised upward. The further back a month sits, the more complete its figure is.
This is a structural feature of the data rather than a fault in it. It matters here because the months being compared are not equally mature: April has had longer to fill in than June has.
The tiers changed system size more than they changed demand
The second mechanism is the design of the change itself. From 1 May 2026 the certificate factor fell from 8.4 to 6.8, and support became tiered by capacity: the factor applies in full to the first 14 kWh, at 60 per cent between 14 and 28 kWh, and at 15 per cent between 28 and 50 kWh. These settings are set out in the Clean Energy Regulator's certificate entitlement guidance, and the group has covered their operation separately in Cheaper Home Batteries Program: 1 May 2026 changes.
The average registered system size fell from 44 kWh in April to 38 kWh in May and 26.16 kWh in June. That trajectory lands just inside the 14 to 28 kWh band, where the tier still returns 60 per cent of the factor. SunWiz describes the same shift as a move toward mid-scale systems in the twenty to thirty kilowatt-hour range.
A capacity-weighted measure will fall when average system size falls by roughly 40 per cent, even if the number of households buying a battery holds steady. Much of the headline decline is that arithmetic. Buyers have re-sized to the shape of the incentive, which is what a tiered incentive is built to do.
SunWiz characterises the result as a controlled reset rather than a structural decline.
Rooftop solar has not followed the same pattern
Rooftop solar volumes have continued at record levels through the same period, running well ahead of the equivalent point last year. SunWiz projects roughly 350,000 battery installations across 2026, against a battery market that approximately tripled to 221,000 systems over the prior year.
The two markets are being read together in much of the coverage, and they are behaving differently. A slowdown in capacity-weighted battery registrations is not evidence of a slowdown in rooftop solar.
Two consequences for a quote written now
Two practical consequences follow for anyone advising a customer.
The first concerns market commentary. A customer who has read that battery installations fell by more than half is working from a provisional figure that will be revised. Staff should describe the position as a reset in system size following the tier change, not as a market in retreat, and should avoid building a purchasing argument on either reading.
The second concerns sizing. The tier structure means the marginal certificate value of capacity above 28 kWh is small, and above 14 kWh it is reduced. A system should be sized to the household's consumption and to network constraints. Where a customer is weighing additional capacity, the certificate contribution to that additional capacity should be quoted at the tiered rate rather than the headline factor.
The commercial threshold sits separately from this. Systems above 100 kW are governed by a different set of arrangements, and a further change to that ceiling has been announced for 1 October 2026.
Sourcing
The twelve-month certificate creation deadline and the 1 May 2026 factor and tier settings were confirmed against the Clean Energy Regulator's own guidance. The monthly capacity figures, the average system size figures, the 2026 projection and the assessment of the decline are SunWiz's, published on 6 August 2026 and in its July 2026 market commentary. SunWiz is the originating source for the monthly registration series rather than a secondary commentator on it.
Figures for the most recent months should be treated as provisional in any document that will still be read in six months.
Current-status note
This analysis was reviewed on 9 August 2026. It records the certificate settings, registration figures and source commentary available on that date. Recent registration months remain subject to revision, and scheme settings can change. Before using the figures for system design, quoting or investment decisions, confirm the current position with the Clean Energy Regulator (opens in a new tab) and obtain site-specific advice from an appropriately qualified provider. No direct SunWiz report URL, underlying data extract or later revision series was retained with this article. Related records are available in Pulse, and the editorial standards explain how dated commentary is handled.
