500 kW generators, diesel and natural gas

500 kW and 625 kVA are the same set

Generator sets are sold in kW at a power factor of 0.8, so a 500 kW set is a 625 kVA set. A listing for a 500 kVA generator is a smaller unit, 400 kW. Check whether a price is for the standby or the prime rating, because the same engine carries a lower kW figure for prime power.

The current below is computed from 625 kVA. Use it to size the main breaker, the transfer switch and the cable.

Computed. Amps equal kVA times 1,000 divided by the square root of 3 times the voltage. Almost every 500 kW set is built for 480 V or 208 V, and a medium voltage site uses a step up transformer.

500 kW models from the main makers

Every major maker builds a set at 500 kW, in diesel and in natural gas. These are the published ratings for the models we found. Ratings change with voltage, emissions package and duty, so confirm them on the spec sheet for the exact model you are quoted.

From maker pages, spec sheets and dealer listings read November 2026, listed under sources. The Kohler and Cummins DFEK details come from dealer listings of specific units.

Fuel burn of a 500 kW diesel set

A 500 kW diesel set burns roughly 33 to 37 gallons an hour at full load and about half that at half load. That decides the tank. A sub base tank that runs a set for 24 hours at full load has to hold around 850 gallons of usable fuel.

From the spec sheets listed under sources. Gallons are liters divided by 3.785. Hours of runtime equal usable tank gallons divided by the burn rate at your load, so the XQ500's 2,650 liter tank runs it about 21 hours at full load.

Diesel or natural gas, standby or prime

A diesel set stores its fuel on site and starts and takes load fast, which is why it is still the usual choice for emergency backup. A natural gas set runs from the gas line, so there is no tank to refill, and it suits long running or prime power where a strong gas supply is available, according to Generator Source.

Standby is the rating for backup during an outage with a variable load and limited hours. Prime is the rating for running as the main source with no yearly hour limit, and its kW figure is lower, 455 kW against 500 kW on the Cummins C500D6. Buy the rating that matches how the set will run.

Emissions tier at 500 kW

Diesel sets above about 120 to 125 kW became subject to EPA Tier 4 at the start of 2011, according to Power Engineering. A set whose only job is backup power when the utility fails counts as emergency and can carry an earlier tier, which is why so many 500 kW sets for sale are Tier 2 or Tier 3. A set used for prime power, peak shaving or rental is non emergency and has to meet Tier 4 Final, which adds an SCR system and diesel exhaust fluid.

Tell us the duty and we only quote sets that meet it.

New and used 500 kW generator prices

These are public listing and dealer figures, not our prices. Enclosure, controls, the emissions package, voltage and whether a transfer switch comes with the set move the price as much as the brand.

Asking prices are not sold prices. Installation, the transfer switch, permitting, fuel and freight are extra.

Lead times

Generator Source puts lead times for new sets from 500 to 1,000 kW at 4 to 6 months, and over a year for custom built units or when demand is high. Large sets are slow now because data centers buy them in volume.

A surplus or used set that already exists can ship once it is tested and paid for, so the wait is the load bank test, any repairs and the freight. That is why many buyers price a used or new surplus 500 kW unit next to a factory order.

Size, weight and setting the unit

Generator Source puts an enclosed 500 kW set at about 20 to 25 feet long, 8 to 10 feet wide and 10 to 12 feet high, weighing 30,000 to 50,000 pounds or more with its tank. Ask for the shipping weight and dimensions with the quote, and confirm the pad, the crane access and the exhaust route before it ships.

The gear that goes with a 500 kW set

At 480 V the set puts out 752 A, so the transfer switch, the main breaker and the cable all have to be rated above that. The 2015 Kohler 500REOZJB in our price table carries an 800 A main breaker. At 208 V the current is 1,735 A, more than twice as much, which is why large sets for 208 V buildings are often built at 480 V with a step down transformer on the load side.

If the set feeds a medium voltage system it needs a step up transformer of at least 625 kVA, which in standard sizes is a 750 kVA pad mounted unit. Two 500 kW sets can be paralleled on switchgear for redundancy or to grow later. We quote the set, the transformer and the transfer or paralleling gear on one delivered quote, so the ratings line up before anything ships.

How much does a 500 kW generator cost

Depco puts new diesel sets from 200 to 500 kW at $75,000 to $200,000 and from 500 to 1,000 kW at $200,000 to $500,000, before installation. Dealer listings read in November 2026 asked $99,900 and $129,900 for new 2026 Cummins DFEK 500 kW sets, and $69,500 to $89,900 for low hour used units.

How many amps is a 500 kW generator

At 0.8 power factor a 500 kW set is 625 kVA, which is 752 A at 480 V, 1,735 A at 208 V and 601 A at 600 V, three phase.

Is a 625 kVA generator the same as 500 kW

Yes. Generator sets are rated at 0.8 power factor, so 625 kVA times 0.8 is 500 kW. A 500 kVA set is 400 kW.

How much fuel does a 500 kW generator use

About 33 to 37 gallons of diesel an hour at full load. Cat's D500 GC sheet gives 35.7 gal/hr at full load, 28.8 at 75 percent and 18.6 at half load.

How long is the lead time for a 500 kW generator

Generator Source puts new sets in this range at 4 to 6 months and over a year for custom units. A used or surplus set in stock can ship once it has passed a load bank test.

What size transformer goes with a 500 kW generator

A step up transformer of at least 625 kVA, which in standard sizes means a 750 kVA unit, wound for the generator voltage on one side and the site medium voltage on the other.

Can a used Tier 2 500 kW generator be used

Yes, for emergency backup only. A diesel set this size used for prime power, peak shaving or rental has to meet Tier 4 Final, and local air rules can be stricter.