Hipower Systems · HNI Series

Hipower HNI-500

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

500 kW standby natural gas generator with PSI 22L engine. CARB certified for California large-facility natural gas standby.

Hipower Systems Hipower HNI-500 generator — specifications and details
Standby power
500 kW
Voltage options
277/480V
Frequency / Phase
60 Hz · 3-phase
Engine
PSI 21.9L HO · 21.9L
EPA / Emissions
EPA Stationary Spark Ignition
Alternator
Stamford S5L1D-E4
ManufacturingData Centers
Configure & QuoteDownload spec sheet

Overview#

The Hipower HNI-500 is a 500 kW standby natural gas generator powered by the PSI 22LT — a large-frame turbocharged spark-ignited engine in PSI's 22-liter displacement class. At the top of the HNI's PSI V-engine range before transitioning to the very large V12 units, the HNI-500 provides half-megawatt natural gas standby with CARB certification.

Facilities at this scale — large data centers, industrial operations, hospital campuses — increasingly evaluate natural gas standby to avoid the diesel fuel storage, SPCC compliance, and delivery logistics that scale linearly with generator capacity. A 500 kW diesel installation requires a large storage tank, periodic delivery, and DPF maintenance. The HNI-500 replaces that with utility gas supply.

Gas infrastructure is the key consideration: meter capacity, regulator sizing, and pipe diameter must be engineered to deliver the full-load BTU requirement. Utility coordination for high-demand service upgrades may add project lead time.

Engine Platform#

PSI's 22LT is a large turbocharged spark-ignited engine designed for stationary standby and prime duty at 1800 RPM. The PSI 22-liter platform is deployed across multiple generator OEMs in North American standby applications. Maintenance is centered on spark plugs and oil changes — no DPF, no DEF, no high-pressure diesel injection maintenance.

CARB-Certified for California#

CARB certification across the full HNI series (30–1000 kW) makes the HNI-500 one of the few 500 kW natural gas options available in California without requiring a source test or air district variance. This is a significant specification advantage for California project teams.

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
  • Ignition system: Annual inspection
  • Major overhaul: 30,000 hours

Our Service Experience#

OnPoint Generators maintains large natural gas standby generators in the 500 kW class throughout Northern California. At this scale, natural gas standby requires rigorous commissioning, regular load-bank testing, and a documented maintenance program — all services OnPoint provides as part of comprehensive generator service agreements.

Engineering specifications

Acoustic

Enclosure
Sound-attenuated

Documents & downloads

Spec sheets & manuals

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Estimate runtime for the Hipower HNI-500

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 Hipower HNI-500 under standby duty. Field intervals may differ based on load profile, ambient conditions, and fuel quality.

Oil & filter
Every 1000 hours or 12 months
Air filter
Every 500 hours
Spark plugs
Every 1000 hours
Major overhaul
≈ 30,000 hours

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 plugsErosion from natural gas combustion — replace on schedule to prevent misfire under load1,000+minor
Gas pressure regulatorPressure drop at full load — verify regulator capacity and upstream supply line sizing4,380+minor
Ignition moduleCylinder dropout — per-cylinder coil diagnosis required8,000+moderate

Frequently Asked Questions

What engine does the HNI-500 use?
The HNI-500 uses the PSI 22LT — PSI's 22-liter turbocharged spark-ignited engine, a large-frame stationary platform for 500 kW standby duty.
Is the HNI-500 CARB certified?
Yes. The full HNI series (30–1000 kW) is CARB certified. The HNI-500 qualifies for California permit-by-rule without an air district variance.
What gas supply infrastructure does a 500 kW generator require?
At 500 kW, natural gas demand is substantial — approximately 4.9 million BTU/hr at full load, with a 10 PSI inlet pressure requirement. The meter, regulator, and distribution piping must be engineered for this demand. This requires utility coordination and mechanical engineering review.
Is natural gas a reliable fuel for 500 kW standby?
Natural gas via underground infrastructure is unaffected by weather events that cause power outages. For California facilities, utility gas reliability is generally high. High-seismic-risk sites should assess gas supply vulnerability as part of overall standby system risk analysis.
How does the HNI-500 compare to diesel at this power class?
500 kW diesel standby requires a large storage tank (typically 500+ gallons), SPCC compliance, fuel delivery, and DPF maintenance. The HNI-500 eliminates all of these — for California facilities with appropriate gas service, it's a compelling alternative with CARB certification already in hand.
Who services HNI-500 units in Northern California?
OnPoint Generators provides full-cycle service for large Hipower HNI natural gas generators throughout Northern California.

More in the HNI Series

30 to 1,000 kW CARB-certified natural gas and LPG standby — the broadest gas generator range available from a non-Big-4 manufacturer.

View all 17 models in this series →

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