Overview#
The Hipower HGM-120 is a 120 kW stationary natural gas standby generator in Hipower's HGM series. At 120 kW, the HGM-120 is at the upper end of the HGM lineup and covers mid-commercial standby: medical office buildings, multi-tenant commercial suites, and facilities with critical communications or refrigeration loads.
The HGM series' broad voltage support — 120/240V through 277/480V — makes the HGM-120 adaptable to the range of electrical services found in California commercial construction. CARB certification enables standard air district permitting without additional regulatory steps.
Natural gas supply from the utility eliminates diesel storage, SPCC compliance, and fuel delivery logistics. For California facility owners, the combination of CARB certification and utility-supplied gas fuel represents the simplest compliance path to code-required emergency power.
Engine Platform#
The HGM-120 is powered by a General Motors Vortec 5.7LT CAC-GB — a turbocharged, charge-air-cooled variant of the 350 CID (5.7L) V8 with a 1.547:1 reduction gearbox (engine runs at 2,915 RPM, geared down to 1,800 RPM alternator speed). This gearbox configuration extracts 190 hp on natural gas and 178 hp on LPG from the same small-block displacement. Marathon Electric provides the alternator (model 363PSL1607) with SE350 AVR. Service follows standard spark-ignited gas practice: spark plugs and oil at 1000-hour intervals, annual gas system inspection, no DPF or DEF.
CARB-Certified for California#
Hipower's HGM series holds CARB certification for California natural gas stationary standby. The HGM-120 qualifies for permit-by-rule — standard air district approval without source test.
Service and Maintenance#
- Oil and filter: 1000 hours or 12 months
- Spark plugs: 1000 hours
- Air filter: 500 hours
- Gas line and regulator: Annual inspection
- Major overhaul: 30,000 hours
Our Service Experience#
PowerGen maintains Hipower gas generators throughout Northern California. The 120 kW class in the HGM series is appropriate for mid-commercial buildings where the project team prefers a compact stationary gas unit and CARB certification is required.



