100kW generators at a glance

• Rated 100kW (125kVA) standby, typically about 90kW prime
• 347 amps at 208V and 150 amps at 480V, three-phase
• Burns about 5.8 gallons of diesel an hour at three-quarter load
• Sized for a mid-sized commercial building like a grocery store, clinic, restaurant or multi-suite office
• 60Hz units built for North American power
• New and used units in stock, shipping from Colorado, Florida and Texas

100kW generators in stock now

The workhorse size for commercial buildings

A 100kW generator is the workhorse size for mid-sized commercial buildings. It’ll carry a grocery store, a large restaurant, an urgent care or dental clinic, a multi-suite office or a small machine shop through an outage, HVAC and refrigeration included.

Our 100kW stock changes week to week. It usually runs from brand-new units to used standby sets from CAT, Cummins, Generac and others, in both diesel and natural gas.

Every unit is ours. We buy and own our inventory outright, so we can tell you where a generator came from, how it was used and what our technicians found when they went over it. Units ship from our yards in Brighton, Jacksonville, Pensacola and Austin, and we can get them to a site anywhere in the contiguous US, with Canada and Mexico on request.

Not sure 100kW is the right fit? Run your loads through our generator sizing calculator, or call and talk it through with someone who sizes these every day.

What a 100kW generator can power

Most 100kW generators are three-phase, which is what most commercial buildings run on. Typical buyers include:

• Retail and food service: grocery stores, large restaurants, gas stations, convenience stores and pharmacies
• Healthcare: dental clinics, urgent care centers, veterinary offices and assisted living facilities
• Offices and public buildings: multi-suite offices, fire stations, police substations and libraries
• Light industrial: auto repair shops, welding and machine shops, and small manufacturing

At that size you can usually back up the whole building, not just a few circuits. That covers commercial HVAC, walk-in coolers and freezers, kitchen equipment, lighting, point-of-sale systems and server racks, security systems and pumps.

Size for starting loads, not just running loads. Big motors like HVAC compressors and pumps pull several times their running current for a moment when they start, and that’s usually what decides whether 100kW is enough. Our article on what a 100kW generator can power goes deeper.

100kW generator specs

A 100kW standby generator is rated at 125kVA. Amps are three-phase at a 0.8 power factor, from our kVA, kW and amperage chart.

Voltage (three-phase)	Amps
208V	347
240V	301
480V	150
600V	120

Fuel use below is estimated from our fuel consumption charts. Actual use depends on the engine and site conditions.

Load	Diesel (gal/hr)	Natural gas (ft³/hr)
1/4	2.6	510
1/2	4.1	771
3/4	5.8	1,056
Full	7.4	1,308

How 100kW compares with nearby sizes

Size	kVA	Amps at 208V	Amps at 480V	Diesel at 3/4 load (gal/hr)
80kW	100	278	120	Not listed
100kW	125	347	150	5.8
125kW	156	433	188	7.1
150kW	187	520	225	8.4

100kW spec sheet library

Spec sheets for the 100kW models we see most often. Details can change by model year, so check the sheet against the nameplate on the exact unit you’re quoting. Need one that isn’t here? Ask and we’ll find it.

Brand	Model	Fuel	Spec sheet
CAT	D100	Diesel	CAT D100 spec sheet (PDF)
Cummins	C100D6	Diesel	Cummins C100D6 spec sheet (PDF)
Cummins	DGDB	Diesel	Cummins DGDB spec sheet (PDF)
Cummins	DSGAA	Diesel	Cummins DSGAA spec sheet (PDF)
Cummins	C100N6	Natural gas	Cummins C100N6 spec sheet (PDF)
Cummins	GGHF	Natural gas	Cummins GGHF spec sheet (PDF)
Cummins	GGHH	Natural gas	Cummins GGHH spec sheet (PDF)
Generac	SD0100	Diesel	Generac SD0100 spec sheet (PDF)
Generac	SG100	Natural gas	Generac SG100 spec sheet (PDF)
Hipower	HFW-100-T6U	Diesel	Hipower HFW-100-T6U spec sheet (PDF)
Hipower	HGM-100-T6U	Natural gas	Hipower HGM-100-T6U spec sheet (PDF)
Kohler	100REOZJ4 (Tier 4)	Diesel	Kohler 100REOZJ4 spec sheet (PDF)
Kohler	100REOZJF	Diesel	Kohler 100REOZJF spec sheet (PDF)
Kohler	100RZ71	Natural gas	Kohler 100RZ71 spec sheet (PDF)
MTU	DS100	Diesel	MTU DS100 spec sheet, 4R0113 (PDF)
MTU	DS100	Diesel	MTU DS100 spec sheet, 4R0120 (PDF)
MTU	GC6NLT1	Natural gas	MTU GC6NLT1 spec sheet (PDF)
Multiquip	DCA100SSVU	Diesel	Multiquip DCA100SSVU spec sheet (PDF)
Olympian	G100LG4	Natural gas	Olympian G100LG4 spec sheet (PDF)

Browse every size in our full spec sheet library.

What’s included when you buy from us

• An inspection by our EGSA-certified technicians before the unit leaves our yard
• Load bank testing available, so you can see it carry a load before it ships
• Shipping to your site anywhere in the contiguous US, with Canada and Mexico on request
• Photos, the spec sheet and a walkaround video of the actual unit
• A deposit that holds your unit while you finalize, with a clear quote expiration date
• Service after the sale from our teams in Colorado, Florida and Texas

Watch some of our 100kW load banks

100kW generator FAQ

How many amps does a 100kW generator put out? At three-phase and a 0.8 power factor, a 100kW generator delivers about 347 amps at 208V, 301 amps at 240V and 150 amps at 480V. Your electrician will size the breaker and transfer switch from those numbers.

How much fuel does a 100kW generator use? A diesel 100kW unit burns roughly 4.1 gallons an hour at half load and 7.4 at full load. At three-quarter load that’s about 139 gallons over 24 hours. On natural gas, figure about 771 cubic feet an hour at half load and 1,308 at full load.

What can a 100kW generator power? Most mid-sized commercial buildings: a grocery store, a large restaurant, a medical or dental clinic, a multi-suite office or a small shop, including HVAC, refrigeration and lighting. Check your loads with our sizing calculator before you buy.

Is a 100kW generator the same as 125kVA? Yes. Generators are usually rated at a 0.8 power factor, so 100kW of real power equals 125kVA. You’ll see both numbers on spec sheets and nameplates.

What’s the difference between a standby and a prime rating? A standby rating is for backup power during outages. A prime rating is for running as the main power source for long stretches, and it’s often around 10% lower, so a 100kW standby set may carry about 90kW prime. Check the spec sheet for each unit.

Should I buy new or used? Used units cost less and are often ready to ship now, while new units can carry a factory lead time. We stock both. Every used unit lists its hours and year, and we’ll send photos and a walkaround video of the actual generator before you commit.

How much does a 100kW generator cost? Price depends on whether it’s new or used, its hours, brand, fuel type and enclosure. Tell us about your site and we’ll send pricing on every 100kW unit that fits.

Can I rent a 100kW generator instead? Yes. Our rental teams in Colorado, Florida and Texas can set you up for a short-term job, an event or while you wait on a permanent unit. See generator rentals.

Get pricing on a 100kW generator

Tell us what you’re powering and when you need it, and we’ll send pricing on every 100kW unit that fits. Call 877-866-6895, text us for a quote or request one online. Want to see the unit first? Ask for a walkaround video.