Generac · MG Series (Modular Gaseous)

Generac MG500

500 kW standby / 450 kW prime · Natural Gas / LPG · Liquid-cooled

500 kW modular natural gas standby generator system. Factory-paralleled for N+1 redundancy.

Standby power
500 kW / 450 kW prime
Voltage options
120/208V, 120/240V, 277/480V, 346/600V
Frequency / Phase
60 Hz · 3-phase
Engine
Generac 25.8L V12 SI · 25.8L
Alternator
Generac K0500124Y23
CommercialManufacturingHealthcareData CentersGovernment
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Overview#

The Generac MG500 is a 500 kW modular natural gas generator rated at 500 kW / 625 kVA standby (450 kW / 563 kVA prime) at 60 Hz. It uses a Generac turbocharged/intercooled 25.8L V12 spark-ignited engine with a 95-quart crankcase capacity. Built on the Modular Power System (MPS) platform with a Power Zone Pro Sync controller, the MG500 enables N+1 redundancy configurations where multiple units operate in parallel. The open-set footprint of 154.4 x 70.5 x 74.9 inches fits many mechanical room configurations.

Our Service Experience#

The MG500 uses the Generac 25.8L V12 turbocharged/intercooled engine at 500 kW (204 psi BMEP per the spec sheet). Exhaust temperatures reach 1,380 F at rated output — turbocharger and exhaust valve condition monitoring are important service priorities. With 12 spark plugs per unit and a 95-quart crankcase (approximately 24 gallons of oil per change), service events are significant. Gas supply design is critical at 5,862 CFH demand at full load. The 24.5-gallon coolant system capacity requires proper antifreeze management.

Engineering specifications

Physical

Length
154.4 in
Width
70.5 in
Height
74.9 in
Dry weight
9,386 lb

Documents & downloads

Spec sheets & manuals

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Estimate runtime for the Generac MG500

Adjust load percent and tank size to estimate runtime. Pre-filled with this model's spec where available.

Estimate runtime on this tank

Fuel demand at 75% load

5,250,000 BTU/hr≈ 5250.0 cf/min @ 1,000 BTU/cf

On utility natural gas the runtime is generally unlimited provided the supply line and meter can deliver this BTU/hr at the engine's required inlet pressure (typically 5–14" WC residential, up to 5 psi commercial). Confirm against the OEM's published fuel-pressure spec.

Service intervals

Manufacturer-recommended intervals for the Generac MG500 under standby duty. Field intervals may differ based on load profile, ambient conditions, and fuel quality.

Oil & filter
Every 500 hours or 12 months
Air filter
Every 1000 hours
Spark plugs
Every 2000 hours
Load bank test
Every 12 months

Common failure modes

What we've seen fail on this platform. Use as a service-planning reference, not a diagnostic — actual failure modes depend heavily on duty cycle and maintenance history.

ComponentSymptomTypical hoursSeverity
Spark plugsMisfiring, rough running, reduced power output2,000+minor
Gas regulator / fuel trainUnstable speed, hard starting, fuel pressure faults15,000+moderate
Paralleling controller synchronizationFailed sync, load sharing imbalance, hunting20,000+moderate
BatteryFailed to start, slow cranking8,760+minor

Frequently Asked Questions

What is the difference between the MG500 and the SG500?
The MG500 is a 500 kW gaseous generator built on Generac's Modular Power System (MPS) platform using a turbocharged/intercooled 25.8L V12 engine with factory-integrated paralleling capability. The SG500 uses the same 25.8L V12 engine platform but is configured as a standalone unit. The MG500's MPS architecture enables N+1 redundancy configurations and the ability to service one unit while others continue operating.
What fuel types does the MG500 support?
The MG500 supports both natural gas and liquid propane (LP/LPG). Natural gas is the most common fuel choice as it eliminates fuel storage requirements and provides unlimited runtime with utility gas service.
What voltages are available?
The MG500 supports three-phase configurations: 120/208V, 120/240V, 277/480V, and 346/600V at 60 Hz.

Compatible equipment

Transfer switches

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