Sizing solar and storage together
Two schemes changed and they now pull in the same direction, which changes what a sensible design looks like rather than just what it costs.
Two changes, two schemes
From 1 September 2026, NSW supports commercial battery storage through the Peak Demand Reduction Scheme1. Two of the three activities require solar on site, at a fixed ratio to the battery2.
From 1 October 2026, subject to the regulations, the federal small-scale scheme3 covers solar up to 1 MW, applying its support upfront rather than through large-scale accreditation.
Different levels of government. Different mechanisms. No coordination between them. Put them side by side anyway, and the second change pays for the condition attached to the first.
Why that matters
A site that wanted storage was, until September, looking at a battery business case on its own.
It is now looking at a battery incentive that requires an array, and at an array that is materially better supported than it was a month earlier.
The two reforms were not designed as a package. For a commercial site scoping both, they behave like one.
What this changes in practice
Solar and storage stop being sequential decisions.
Size the array without the battery in view and you risk failing the ratio, which means the battery incentive is gone rather than reduced.
Size the battery without the array in view and you risk a proposal that does not qualify at all, or one that forces an expensive array resize late in the design.
They are now a single design problem with two eligibility tests attached, and the tests are set by different schemes with different rules.
What a combined design has to satisfy
Four things, and they interact.
The battery capacity band for the activity your building falls under2. The solar ratio, demonstrated against the actual proposed array2. The array size, against the federal ceiling and against what the roof and connection will carry. And the switchboard and metering, which decide whether either can be energised as designed.
Miss one and the design still works electrically. It just stops qualifying.
If a capex round is coming, scope solar and storage as one piece of work rather than two. If you already have separate proposals from separate suppliers, they are worth reading against each other before either is awarded. That is where the ratio problem shows up.
Why this is a design question, not a shopping question
This is the clearest case for the way we work. The right array and the right storage for your site are decided together, against your own usage, and neither number can be read off a package.
So the packages on this site are a starting point and a price floor. The system you end up with is modelled from your bill.
Sources
- Peak Demand Reduction Scheme. NSW Climate and Energy Action.
- NSW commercial battery rebate: how the new PDRS incentives work. Solar Choice.
- Small-scale Renewable Energy Scheme. Clean Energy Regulator.
We check this for your address
Incentives change, and they change by building, by capacity and by whether there is already solar on the site. Working out which ones apply to you is part of the design, not an extra.