Storage
Commercial batteries: when they pay, and when they don't
Storage is a second decision, not part of the first. Here is the arithmetic that decides it, and what New South Wales pays for peak demand reduction.
The order matters
Solar first, storage second
A commercial solar system pays for itself by covering power the site would otherwise buy. That case is usually straightforward: the load is there, the generation matches it, and the arithmetic is a few numbers off a bill.
A battery is a different proposition. It rarely earns much by storing your own cheap daytime energy for the evening, because the spread between what you save and what the storage costs per cycle is thin. Where it earns money is in two narrower places: cutting a demand charge, and being paid to reduce peak demand under a scheme that exists for that purpose.
So the order matters. Size the solar against your daytime load first (the guide covers how), then test storage against what is left over.
The two real cases
Where a commercial battery earns its keep
Demand charge reduction
Self-consumption on a constrained site
Worked example
A cold store that runs all night
Take a Brisbane cold store using about 1,500 kWh a day, spread fairly evenly across 24 hours because the refrigeration never stops. It puts in a 100kW solar system, which makes about 145,000 kWh a year, or about 400 kWh on an average day.
What solar does. Because the load is steady, the site uses about 90% of the solar itself, about 360 kWh a day. That covers roughly a quarter of the day’s power. At $0.28 a kWh saved and $0.05 for what goes to the grid, the solar saves about $37,000 a year. The overnight three-quarters of the bill is untouched, because the panels are not making power then. So yes, solar saves real money on a site with an overnight load. It just cannot reach the overnight part.
What a battery could add. The obvious idea is to store solar for the night. On this site, only the 10% the cold store does not use is spare, about 14,500 kWh a year. Stored and used at night instead of being sent to the grid, each kWh is worth $0.28 rather than $0.05, so the gain is about $3,300 a year, before charging losses and cloudy days. Compare that with the battery’s price after any discount, over the years its warranty covers. For most cold stores it will not come close, which is why the demand charge, not overnight storage, is usually the case worth testing.
The full payback table for this and other site types is on commercial solar cost. These are example figures, not our prices or a quote.
Federal
The federal battery discount covers businesses too
The Cheaper Home Batteries Program isn’t only for homes. Households, businesses and community organisations can get a discount of around 30% on the upfront cost of a battery between 5 kWh and 100 kWh of nominal capacity, created as STCs the same way the solar discount is and taken off the installed price.
Two limits matter for a commercial site. Certificates are only created for the first 50 kWh of usable capacity, so a battery near the 100 kWh ceiling gets no more support than a 50 kWh one. And since 1 May 2026 the support per kWh steps down as the battery gets bigger: every kWh above 28 earns less than the first 28. A battery above 100 kWh sits outside the program entirely.
New South Wales
The NSW Peak Demand Reduction Scheme
New South Wales runs a scheme that pays for capacity able to reduce demand during peak periods, administered by IPART. Since 1 September 2026 it has covered business batteries through two activities: BESS4, for small and medium business sites with more than 20 kWh and up to 200 kWh of usable capacity, and BESS5, for commercial, industrial and community batteries above 200 kWh and up to 30 MWh. The value is created as Peak Reduction Certificates that an accredited provider claims and passes through, normally as a discount on the installed price rather than a payment to you.
This is the one state-level mechanism on this site that can move a commercial storage decision on its own, which is why New South Wales gets a battery page rather than a generic state page.
What we don’t print: certificate values. Peak Reduction Certificates trade at a price that moves, and each activity has its own eligibility conditions. So what a battery earns under the scheme is worked out, and checked, on the day a proposal is written. We would rather show you nothing than an incentive figure that has moved.
If your site is in New South Wales and you want the current numbers applied to your actual load, send a bill and they will be in the proposal, checked on the day it is written.
Before you sign
What to ask about a battery quote
What demand charge is this actually reducing?
Ask for the line on your bill it targets and the modelled reduction, not a percentage.What happens on a bad day?
A battery sized to an average peak will miss the worst one, and the worst one may be what sets the charge.Warranty in cycles, not years
A commercial battery cycling daily ages differently to a residential one. Ask for throughput and end-of-warranty capacity.Who claims the certificates?
And what do you actually receive? If a scheme value is in the quote, ask whether it is assumed or confirmed.Where does it go?
Commercial batteries need space, ventilation and clearances that suit a switchroom or a compound, not a plant cupboard.
Questions
Common questions
Should we add a battery to a commercial solar system?
Usually not at the same time, and usually not for the same reason. Solar earns its money by covering daytime load; a commercial battery earns its money mostly by reducing demand charges or by being paid to reduce peak demand. Those are separate cases with separate arithmetic. Size the solar against your load first, then test whether storage adds anything on top.
What is a demand charge and can a battery reduce it?
Many commercial tariffs bill a capacity charge set by the site's highest demand interval in a billing period, separate from the energy you use. A battery can shave that peak if the peak is predictable and the battery is sized and controlled to cover it. If your peak falls in the middle of a sunny day, solar may already be doing the job. Read your own tariff before anyone sells you storage on this basis.
Is a commercial battery worth it without an incentive?
It depends almost entirely on your demand charge and how sharp your peak is. A site with a flat load profile and a small capacity charge rarely justifies storage on economics alone. A site with a short, severe peak can. This is a case where the answer genuinely differs site to site, which is why we read the bill rather than quote a rule of thumb.
Will solar save money for a cold store that runs overnight?
Yes, but only on the daytime part of the bill. Refrigeration runs all day, so a cold store uses almost all its solar itself, which makes the saving per kW strong. On our example, a 100kW system on a Brisbane cold store using 1,500 kWh a day saves about $37,000 a year, covering roughly a quarter of its power. The overnight load is untouched. Storing the small solar surplus in a battery for the night is worth only about $3,300 a year on the same example, so a battery on a site like this is usually tested against the demand charge instead.
Last updated 15 October 2026.
Storage only works against a real load profile
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