Commercial Generator Install Brisbane: 2026 Cost and Sizing Guide
Brisbane commercial generators are a five figure decision wrapped in technical jargon. Most quotes you will see leave out the fuel tank, leave out the Automatic Transfer Switch, leave out the concrete pad and somehow always leave out the Energex notification. This guide gives you the real 2026 SEQ Sparky numbers for a turnkey commercial generator install, the right size for your load, the difference between standby and prime power, and what the Energex EWR process looks like for a parallel grid connection.
I am Anthony Nuich, owner of SEQ Sparky and a QLD licensed electrical contractor (Licence 90899). We have installed generators for Brisbane cafes, medical clinics, supermarkets, data rooms and small industrial sites. Every install is owner managed, fully insured to $20 million, and finished with Form A and Form B compliance so the system stands up to Energex inspection and your insurer never has a question.
Brisbane commercial generator cost in 2026 at a glance
Pricing comes down to four things: generator size in kVA, manual or automatic transfer, fuel tank capacity, and switchgear protection complexity. Here are the real ballpark figures SEQ Sparky uses for Brisbane commercial generator installs in 2026.
| Generator size | Typical site | Turnkey 2026 cost |
|---|---|---|
| 10 to 15 kVA | Cafe, small retail, small office | $18,000 to $28,000 |
| 20 to 30 kVA | Restaurant, medical clinic, small servo | $25,000 to $42,000 |
| 40 to 60 kVA | Supermarket, medium clinic, dental | $32,000 to $58,000 |
| 80 to 100 kVA | Warehouse, factory, larger supermarket | $55,000 to $95,000 |
| 150 to 200 kVA | Industrial site, data room, hospital wing | $95,000 to $165,000 |
| 250 to 500 kVA | Large industrial, distribution centre | $165,000 to $345,000 |
Turnkey includes the generator itself, concrete pad, fuel tank (24 to 100 hour capacity), Automatic Transfer Switch, protection relays, all cabling from generator to switchboard, Energex EWR, Form A and Form B compliance, commissioning and load testing.
Standby vs prime vs continuous: pick the right duty rating
- Standby (ESP). Backup only, expects to run during mains failure for short periods. Rated for 200 hours per year max. Cheapest option. Right for offices, retail, most clinics.
- Prime power (PRP). Continuous variable load with up to 10 percent overload for 1 hour in 12. Right for sites without grid, or where the generator runs daily.
- Continuous (COP). 24/7 unlimited operation at rated load. Most expensive build. Right for remote sites and base load applications.
Most Brisbane commercial generators are standby rated because they only run when the grid drops. If you are paying for a continuous rated unit for what is actually standby duty, you are paying twice what you need.
How to size the generator properly
Sizing is where most cheap generator quotes go wrong. Undersize and you fry the alternator under starting loads. Oversize and you burn diesel inefficiently and shorten engine life from wet stacking. The right size considers:
- Steady state load. Sum of all running loads (lighting, refrigeration, computers, EFTPOS, point of sale)
- Motor starting loads. Air conditioners, walk in cold rooms and lifts draw 3 to 6 times their running current for 1 to 3 seconds at start
- Future growth. 20 percent headroom for new equipment or load expansion
- Operating altitude and ambient temperature. Brisbane summers derate generator output by 5 to 8 percent
- Non linear loads. LED lighting, VFDs and switched mode power supplies create harmonics that derate the alternator
SEQ Sparky does a free site load calculation before quoting. We measure your actual demand profile over 5 to 7 days with a logging meter, then size the generator to match.
Automatic Transfer Switch (ATS): the brain of the install
The ATS is the kit that decides which source feeds the building. When mains drops, it senses the failure, signals the generator to start, waits for stable output, then switches the load over. When mains returns, it reverses the process and switches back, then shuts the generator down after a cool down cycle.
Three ATS levels for Brisbane commercial work:
- Open transition. Generator runs at no load until ATS transfers. Brief power gap of 1 to 3 seconds during switch. Cheapest. Right for most retail and small commercial.
- Closed transition. Generator synchronises to mains before switching. No power gap. Required for medical sites, data rooms, lifts and any site where a 1 second gap causes problems.
- Soft loading. Generator gradually picks up the load instead of slamming it. Right for sensitive electronics and large motor loads.
Closed transition adds $4,000 to $9,000 to the install. Worth every cent if you have a lift, EFTPOS terminals, or medical equipment.
Fuel tanks: how much runtime do you actually need
Day tanks built into the base of the generator give 8 to 24 hours of runtime. Separate bulk tanks extend to 72 hours, 1 week, or longer depending on storage. For Brisbane Southside the typical commercial runtime needs are:
- 24 hours for most retail and office sites (covers worst case grid outage)
- 48 to 72 hours for cold storage, supermarkets and medical clinics
- 1 week plus for telecoms, data centres and critical infrastructure
Fuel tank cost is $2,500 to $14,000 depending on capacity and bunding requirements. AS 1940 dictates double walled tanks for indoor or near building installs.
Energex EWR and approval process
Any generator that connects to a switchboard on the customer side of the meter requires an Energex Electrical Work Request. The level of approval depends on whether the generator can ever run in parallel with the grid:
- Standby only with break before make ATS. Standard EWR, no special approval. SEQ Sparky handles the paperwork.
- Closed transition with brief parallel operation (under 100 milliseconds). Requires Form 18 connection approval and protection relay settings approved by Energex.
- Continuous parallel operation. Full embedded generator approval, protection coordination study, anti islanding relay, export compliance.
Full information on our process is in our commercial electrician Brisbane service page.
What is included in a SEQ Sparky commercial generator install
- Free 5 to 7 day load logging and sizing calculation
- Generator supply (FG Wilson, Cummins, Caterpillar, Olympian or equivalent)
- Concrete pad and noise enclosure design to AS 2436 site noise limits
- Fuel tank sized to runtime, with bunding and level monitoring
- ATS supply and install (open or closed transition as required)
- Protection relays, neutral switching and earthing
- All cabling from generator to main switchboard
- Switchboard modifications to accept the generator feed and ATS
- Energex EWR lodgement and inspection
- Commissioning, load bank testing and operator training
- Form A and Form B compliance certificates
- Optional annual service contract
Diesel vs natural gas vs LPG: fuel choice for Brisbane sites
- Diesel. Standard for true emergency backup. Unlimited storage, no supply dependency. Higher emissions and noise. Most common in Brisbane.
- Natural gas. Clean burning, less maintenance, unlimited runtime if town gas supply holds. Loses backup if gas supply also fails (rare but possible). 20 to 35 percent more upfront.
- LPG. Right for sites without town gas but wanting cleaner burn. Storage limits runtime.
- Bi fuel. Diesel with gas assist. Reduces diesel consumption 60 to 70 percent during normal operation, falls back to pure diesel if gas fails. Premium price.
Service and maintenance: what you should budget
A commercial generator that never runs is more dangerous than one that runs weekly. Stale fuel, dried gaskets, condensation in the crankcase, dead batteries. Without scheduled maintenance you find the problem at the moment you most need the generator.
SEQ Sparky annual service includes oil and filter change, fuel sample test, load bank test under 80 percent rated load for 1 hour, battery and starting check, ATS exercise, and a written service report for your records. Annual contract pricing:
- Up to 30 kVA: $850 to $1,200 per year
- 30 to 100 kVA: $1,200 to $1,800 per year
- 100 to 250 kVA: $1,800 to $2,400 per year
- 250 kVA plus: quoted per site
Choosing the right contractor for a commercial generator install
- QLD electrical contractor licence number, not just electrician licence
- Public liability insurance certificate (we hold $20 million)
- Written load study and sizing calculation before quoting
- Energex EWR included in price, not a surprise extra
- Form A and Form B compliance included
- Generator brand and model specified, not “equivalent”
- Service contract option included for ongoing reliability
If you are also reviewing your switchboard for capacity, see our switchboard upgrade cost guide and the three phase power decision guide. Most commercial generator installs trigger at least a switchboard review.
Frequently asked questions
How much does a commercial generator cost to install in Brisbane in 2026?
A 15 kVA standby diesel generator for a small business installs for $18,000 to $28,000 turnkey. A 50 kVA unit for a medium retail or hospitality site sits at $32,000 to $55,000. Larger 100 to 200 kVA units for warehouses and supermarkets range from $65,000 to $145,000 depending on fuel tank size and switchgear requirements.
Do I need an Automatic Transfer Switch (ATS) for my generator?
For any business that needs power to come back on without staff intervention, yes. An ATS senses mains failure and starts the generator within 10 to 30 seconds. For occasional backup where someone can manually flip a changeover, a manual transfer switch saves $3,500 to $8,000 but loses the automation.
What size generator do I need for my Brisbane business?
Size to your continuous load plus 25 to 40 percent headroom. A typical small office or cafe runs 8 to 15 kVA. A medium supermarket or medical clinic needs 30 to 60 kVA. A small industrial workshop sits at 50 to 100 kVA. We do a full load calculation before quoting because oversizing wastes money and undersizing damages the generator.
How long does a commercial generator install take?
A standard standby install with concrete pad, fuel tank, ATS and switchgear takes 7 to 14 working days from start to commissioning. Add 2 to 3 weeks lead time for the generator itself. Energex notification and final inspection adds another 1 to 2 weeks at the end.
Do I need Energex approval for a generator install?
Yes for any grid connected system. An Electrical Work Request (EWR) must be lodged because the generator is connected to your switchboard alongside the mains supply. Synchronous parallel operation requires additional approval and protection relays.
How often does a commercial generator need servicing?
Minimum once a year for standby units, every 250 running hours for active duty, and a full overhaul at 3,000 to 5,000 hours. SEQ Sparky offers annual service contracts at $850 to $2,400 per year depending on generator size.
Can I use natural gas instead of diesel?
Yes for permanently connected sites with town gas. Natural gas generators run cleaner, require less maintenance, and have unlimited fuel runtime. But they cost 20 to 35 percent more upfront and you lose backup if the gas supply itself fails. Diesel is still the standard for true emergency backup.
What is the running cost of a commercial generator?
Fuel burn is the main cost. A 50 kVA diesel under 70 percent load uses around 9 to 12 litres per hour. At $1.95 per litre that is $18 to $24 per hour of running cost. Plus an oil and filter service every 250 hours costs around $450.
Get a real fixed price for your Brisbane generator install
Generator quotes are easy to get wrong. Without a real load study you will either pay for capacity you do not need or end up with a generator that cannot start your air conditioner. SEQ Sparky does the load logging up front, sizes the unit properly, and quotes turnkey including the Energex paperwork.
Call SEQ Sparky on 0431 110 148 or request a quote through the commercial electrician Brisbane service page. Brisbane Southside, owner operated, QLD Licence 90899, fully insured to $20 million.
