BUY New & Used Commercial Backup Generators 500kW-999kW GENERATORS FOR SALE

Industries That Use 500 kW to 999 kW Generators

Here one generator often carries a whole facility, and a self-contained power module on a chassis competes with a set bolted to a pad. Who buys depends on which format the job calls for.

• Data centers: Edge sites, smaller colocation facilities, and single-building IT rooms often start sizing at 500 kW.
• Hospitals: Multi-wing facilities that keep the whole building live on a pad-mount standby set.
• Campuses: Around 600 kW, one set can realistically anchor a cluster of connected buildings that share electrical infrastructure.
• Manufacturing and processing: Plants restarting several large motors, pumps, and fans on one service.
• Rental fleets: The main buyers of containerized power modules and large towables.
• Construction and events: Large sites and temporary installations on trailer units.
• Mining and oil and gas: Remote and off-grid sites where an 800 kW class set is the only power, specified on its prime rating with extended fuel storage.
• Cities and municipalities: Neighborhood-level emergency response and early microgrid projects, where a 750 kW set acts as a temporary utility for a cluster of buildings.

Sizing notes by sector are on our industries served pages.

500 kW to 999 kW Generators at a Glance

• Apparent power: 625 to 1,249 kVA at 0.8 power factor.
• Current: 752 A at 500 kW to 1,354 A at 900 kW at 480V, or 87 to 156 A at 4160V. At 208V the same span runs 1,735 to 3,120 A.
• Diesel burn at full load: 35.7 gal/hr at 500 kW, 42.8 at 600 kW, and 53.4 at 750 kW on our chart.
• Weight: about 10,500 lb for an open Generac SD750 to 22,496 lb for an open Generac SD800. A containerized Cat XQ500 is 27,595 lb with full fuel, plus a 7,450 lb chassis.
• Two common formats: pad-mount diesel standby, many listed as EPA Tier 2, and trailer-mounted units or power modules for rental and temporary duty.
• Decision driver: format and fuel first. A container on a chassis, a sound-enclosed pad set, and a dual-fuel gas set are priced and permitted on different terms.

Narrowing 500 kW to 999 kW Into Three Bands

Most buyers land in one of these once the load list is totaled.

For a single size, see our 500 kW, 600 kW, 750 kW, and 800 kW generator pages.

Trailers, Power Modules, and Standby Sets in Our Yard

Units in this range that we’ve listed, at the kW we listed them:

The hours split cleanly by format. Every used pad-mount standby set above has under 1,750 hours, most under 800, while the used power modules run from 4,785 to 11,147 hours, which fits a life of rental and prime duty. Whatever is on the ground today is in the listings above.

Published Specs for Five Models From 500 kW to 800 kW

Manufacturer figures for a container module, pad-mount diesels, and gas sets:

Two things stand out. The XQ500 is the only Tier 4 Interim unit here, while the pad-mount diesels are Tier 2 for stationary emergency use, and each certification limits where and how a unit can run. And the Kohler 500REZXD is a reminder that a dual-fuel nameplate describes natural gas only. On LP it makes 295 kW, about 59% of its gas rating, so a site counting on LP backup has to size to the lower number.

Diesel Burn From 500 kW to 1000 kW on Our Chart

Our diesel fuel consumption chart has three rows inside this band and none at 800 or 900 kW, so the 1000 kW row brackets the top:

At 500 kW and 600 kW the sheets land almost on the chart: Cat lists 35.9 gal/hr for the XQ500 and Kohler 42.7 gph for the 600REOZVB. Generac’s SD750 comes in under it at every step, at 14.3, 25.6, 38.0, and 49.7 gal/hr. The SD800 goes the other way, listing 74.4 gal/hr at full standby, more than the chart’s 1000 kW row.

At full load a 500 kW set burns about 857 gallons in 24 hours and a 750 kW set about 1,282. The XQ500 carries a 700-gallon double-wall tank that Cat rates for 24 hours at 75% of prime plus 10%. Pad-mount tanks vary more: the SD750’s sub-base tanks run 334 gallons (6 hours) to 2,002 gallons (40 hours), and Kohler lists a 3,052-gallon tank for the 600REOZVB where state code calls for 72 hours.

Current at 208V Through 4160V Across the Band

Three-phase current at 0.8 power factor, from our generator amperage chart:

At 208V, current passes 1,700 A at the bottom of the band and 3,000 A near the top, so 480V is the working voltage for most of this range. Generac’s sheets list 1,129 A at 480V for its 750 kW sets and 1,203 A for the SD800. A towable or module has to match the site’s voltage at the connection point. Our power calculators will check the load total first.

Power Module on a Chassis or Pad-Mount Standby Set?

A power module suits temporary, rental, or multi-site duty; a pad-mount set suits permanent standby at one address.

Cat’s XQ500 puts the set in a 20 ft ISO high cube container on a 2-axle chassis with anti-lock brakes, with its own tank, silencer, and enclosure, rated 72 dB(A) at 7 m with 110% spill containment for engine fluids. On the chassis it measures 240 x 96 x 150 inches. That clears the 102-inch federal width standard, and at 12.5 ft it sits under the 13.6 to 14.6 ft range of state height limits FHWA reports, but each move still needs a route and permit check.

A pad-mount set is bought by the piece: Kohler’s 600REOZVB weighs 10,770 lb wet as an open set, and its housing choices run from 91 dB(A) in a steel weather enclosure to 76 dB(A) in a steel sound enclosure. Adding the 541-gallon sub-base tank takes the steel sound package to 17,003 lb, which ships assembled with lift lugs for a crane and spreader bar. Units on running gear are under trailer-mounted generators and permanent sets under industrial standby generators.

Is 500 kW Where a Data Center Starts?

For edge sites, smaller colocation facilities, and single-building IT loads, often yes.

Operators commonly begin sizing at 500 kW, then scale up with paralleled units as the facility grows. What matters most here is transfer speed: the switchover has to happen within seconds to avoid interrupting servers, which favors diesel. Pad-mount Tier 2 standby sets such as the Cummins DFEK and Caterpillar C15 we’ve listed at 500 kW fit that role, and a rental module like Cat’s XQ500 can carry a site while a permanent set is installed or replaced.

What Happens to the Rating on Natural Gas or LP?

Natural gas usually holds the standby rating if the gas service can deliver the flow; LP can cut it sharply.

Gas sets in this band are rated against a specific supply. Kohler’s 500REZXD needs 7.0 to 11.0 in. H2O at the inlet and draws 5,888 cfh at full load. Cummins’ C600N6 draws 9,557 cfh at full load on 14 to 20 in. WC, and Generac’s SG750 needs 8,370 scfh on 14 to 20 inches of water column. If the service can’t hold that pressure and flow, the set won’t make its nameplate. LP as a backup fuel is the bigger limit: the 500REZXD drops from 500 kW to 295 kW when it switches over. Gas units we list, up to the 880 kW Cummins 880GFLC, are under industrial natural gas generators, with diesel sets under industrial diesel generators.

Standby or Prime, and What Used Looks Like Here

Compare the rating that matches your duty: standby for outage backup, prime for long runs or off-grid power.

Most sheets in this band publish both, about 7% to 10% apart: 500 and 455 kW on the XQ500, 600 and 555 kW on the 600REOZVB, 800 and 720 kW on the SD800. Generac does not offer the SD750’s 675 kW prime rating in the U.S. at all. On used equipment, format predicts hours, as the yard table shows. New is the answer when a spec requires a factory warranty, a current emissions tier, or new equipment outright. Browse used industrial generators and new industrial generators side by side.

Rent the Module or Own the Set?

Rent a module for turnarounds, construction phases, events, or bridging a failed unit; own the set when it protects a facility permanently.

A standby set runs a few hours a year on a permanent pad and fuel system. Our rental side, Stag Power Rentals, handles short-term work, and our generator financing options help when budget timing is the obstacle.

Below 500 kW or Above 999 kW: The Neighboring Ranges

A diesel set run lightly loaded for long stretches develops wet stacking, so oversizing costs more than the purchase.

If the load sits right at 500 kW with little motor start, compare our 400 kW generators. If it runs past 999 kW, the next step is our 1000 kW generators. You can also browse every output we carry on shop by kW.

Inspected, Load Tested, and Backed After the Sale

Every generator we sell goes through a 22-point inspection and load bank testing before it ships, which matters most on high-hour power modules coming off rental duty. We’ve been buying and selling industrial generators for over a decade. Each purchase carries our 30-day IronClad warranty, and our service and maintenance team covers scheduled testing, industrial generator repair, and emergency service after delivery.

Ready to Buy a 500kW – 999kW Generator?

Tell us your load, voltage, fuel, and whether the unit stays on one pad or moves between sites, and we’ll match it to a standby set or a power module. Look through our used industrial generators and new industrial generators, or contact us and we’ll work the sizing with you.