What can a commercial battery actually do?

A commercial battery can shift energy from one part of the day to another, reduce some demand peaks, provide backup to selected loads and help a site make better use of solar that would otherwise be exported or curtailed.

Those are different jobs. A battery sized for evening energy shifting may not have enough power to shave a short industrial demand spike. A battery designed for demand management may not provide the runtime needed for backup.

The first question is not "How big a battery should we buy?" It is "What problem are we paying the battery to solve?"

Using a battery to manage peak demand

Some commercial tariffs include demand charges based on the site's highest measured demand over a defined period. A battery can discharge when load rises and reduce the peak seen by the grid.

This can work well when peaks are predictable and the battery control system has enough power to respond. It is less convincing when the tariff barely charges for demand or the site's peaks are too large, too long or too erratic for the proposed battery.

Ask for the historical demand events to be shown against the proposed battery power in kW. That is more useful than a generic claim that storage will "reduce peak demand".

Using a battery to shift solar

A business with strong solar production and meaningful late-afternoon or evening demand can store some daytime surplus and use it later.

The economics depend on the spread between the value of exported solar and the cost of electricity the battery later avoids, after allowing for battery losses and degradation.

If nearly all solar is already consumed on site during the day, there may be little surplus to charge a battery. If the site has a low export limit, storage can also create room for more useful solar production by absorbing energy that might otherwise be curtailed.

Backup is a design feature, not a default battery function

A commercial battery does not automatically keep a whole site running during a blackout.

The system needs suitable inverter capability, switching, protection and a defined backup architecture. Large motors, refrigeration compressors, lifts, pumps and other high-starting-current loads can make whole-site backup difficult or expensive.

For many businesses, the better question is which loads are genuinely critical. Communications, security, selected refrigeration, servers, controls and emergency circuits may need very different power from the entire facility.

Ask how many kilowatts the battery can continuously deliver in backup mode, how much usable energy is reserved, which circuits remain live and whether solar can recharge the battery while the grid is down.

Can a small business receive the federal battery discount?

Eligible businesses can access the Cheaper Home Batteries Program. The program supports battery systems connected to new or existing solar and is delivered through STCs.

Eligible battery systems can have a nominal capacity from 5 kWh to 100 kWh. The scheme calculates support on up to the first 50 kWh of usable capacity.

For installations from 1 May 2026, the STC support is tiered. The first 14 kWh of usable capacity receives the full factor, the next 14 kWh receives 60 per cent, and usable capacity above 28 kWh to 50 kWh receives 15 per cent. The underlying factor declines over time.

This means a larger battery can still be useful, but the federal discount does not increase at the same rate as capacity once the system moves through those tiers.

See the commercial incentives guide ↗

Commercial batteries need two sizing numbers

Battery capacity in kWh tells you how much energy can be stored. Battery power in kW tells you how quickly that energy can be delivered.

A 100 kWh battery with 20 kW of continuous output behaves very differently from a 100 kWh battery with 80 kW of output. One may cover a long modest load. The other may be much better suited to short, high-power events.

Data worth collecting before requesting a battery proposal

  • At least 12 months of interval consumption and demand data.
  • Current solar generation and export data, if solar already exists.
  • The network tariff and retail energy contract.
  • Any approved solar export limit.
  • Critical loads and required backup duration.
  • Planned EV charging, electrification or new machinery.
  • Required battery warranty, cycling assumptions and expected usable capacity over time.

Commercial storage should be modelled with the operating strategy included. The same battery can produce very different savings depending on when it charges, when it discharges and what value the control system is targeting.

Related commercial guides

Sources and further reading

Source labels identify who published each reference, not an independent endorsement. Confirm current requirements and exact product terms before purchasing.