Diesel generator fuel consumption, litres per hour, by rating and load
A working chart for budgeting and sizing conversations, with the assumptions stated openly rather than buried. Load factor moves the number more than nameplate rating does, so the table is laid out by load, not by a single "at full load" figure.
How much diesel does a generator set burn per hour?
As a planning estimate, litres per hour equals rated kW multiplied by load factor multiplied by specific fuel consumption of roughly 0.27 L/kWh near full load rising to about 0.33 L/kWh at light load. A 100 kW set draws about 27 L/h at full load, 15 L/h at 50% load and 8 L/h at 25% load. Part-load running costs more fuel per kilowatt-hour produced because friction, pumping and heat losses do not fall as fast as the load. Confirm against your own set's data sheet or measured litres per hour before using a figure commercially.
- Litres per hour = rated kW x load factor x specific fuel consumption (L/kWh).
- Specific consumption assumed here: 0.27 L/kWh at 100% load, 0.33 L/kWh at 25% load.
- Load profile over a year matters more for fuel budgets than nameplate rating.
- Indicative planning figures only — not a specification for any particular set.
- Range covered
- 20 – 500 kW
- Load points
- 25 / 50 / 75 / 100%
- Assumed BSFC
- 0.27 – 0.33 L/kWh
- Annual basis
- Per 1,000 running hours
Fuel consumption in litres per hour
| Rated output | 25% load | 50% load | 75% load | 100% load | Litres / 1,000 h at 50% |
|---|---|---|---|---|---|
| 20 kW | 1.7 L/h | 2.9 L/h | 4.1 L/h | 5.4 L/h | 2,900 L |
| 30 kW | 2.5 L/h | 4.3 L/h | 6.2 L/h | 8.1 L/h | 4,350 L |
| 50 kW | 4.1 L/h | 7.2 L/h | 10 L/h | 14 L/h | 7,250 L |
| 75 kW | 6.2 L/h | 11 L/h | 15 L/h | 20 L/h | 10,875 L |
| 100 kW | 8.3 L/h | 14 L/h | 21 L/h | 27 L/h | 14,500 L |
| 150 kW | 12 L/h | 22 L/h | 31 L/h | 41 L/h | 21,750 L |
| 200 kW | 17 L/h | 29 L/h | 41 L/h | 54 L/h | 29,000 L |
| 250 kW | 21 L/h | 36 L/h | 52 L/h | 68 L/h | 36,250 L |
| 300 kW | 25 L/h | 44 L/h | 62 L/h | 81 L/h | 43,500 L |
| 400 kW | 33 L/h | 58 L/h | 83 L/h | 108 L/h | 58,000 L |
| 500 kW | 41 L/h | 73 L/h | 103 L/h | 135 L/h | 72,500 L |
Figures are calculated, not measured: rated kW x load factor x the specific fuel consumption stated in the header assumptions above. Real sets vary with engine age, ambient temperature and altitude, alternator efficiency, fuel density and whether the rating is prime or standby. Treat this as a budgeting tool and confirm against your own data sheet.
How to measure your own set
- Fix the load. Use a load bank or a repeatable site load, and record the kW actually carried — not the nameplate.
- Start from a known fuel volume: a calibrated day tank, an installed flow meter, or a measured top-up to a fixed level.
- Run for enough hours that refuelling error is small against total burn — several hours at minimum, longer on small sets.
- Divide litres by hours. Record ambient temperature, fuel batch and load for each run.
- Repeat. Two or three matched runs tell you the spread; one run tells you almost nothing.
Typical engine size behind each rating
| Rating band | Typical displacement | Unit |
|---|---|---|
| 20 – 30 kW | 2.5 – 4.0 L | HydroHub™ A-900 or H-Power |
| 50 – 100 kW | 4.0 – 7.0 L | HydroHub™ H-Power |
| 150 – 300 kW | 7.0 – 12.0 L | HydroHub™ DH-Power |
| 400 – 500 kW | 12.0 – 16.0 L | HydroHub™ DH-Power |
Displacement bands are typical of equipment in each rating class, not a specification of your set. Combustion-enhancement units are matched to swept volume, so size on the actual engine. See generator-set classes for which duty cycles suit fitment and which do not.
What this chart is not
This is a baseline reference. It makes no fuel-saving, emissions or performance claim for any product, and nothing on this page should be read as a projected result from fitting equipment. Establish your own measured baseline first; any change afterwards has to be demonstrated on your set, at a matched load, on the same fuel, over enough hours to clear normal variation.
Generator fuel consumption questions.
How much diesel does a generator use per hour?
- As a planning figure, litres per hour is roughly the rated kW multiplied by the load factor multiplied by 0.27 to 0.33 L/kWh — the lower figure near full load, the higher figure at light load. A 100 kW set at 50% load is therefore about 14–15 L/h, and the same set at 25% load about 8 L/h. Your own set will differ with engine age, ambient conditions, fuel and alternator efficiency.
Why does part-load running use more fuel per kilowatt-hour?
- Friction, pumping and heat losses do not fall as fast as the load does, so each kilowatt-hour produced at 25% load costs more fuel than one produced at 75%. This is why a lightly loaded set can burn a surprising amount of diesel for the electricity it actually delivers, and why load profile matters more than nameplate rating when budgeting fuel.
Are these figures a specification?
- No. They are indicative planning estimates derived from typical specific fuel consumption ranges for modern diesel generator sets. Use them for budgeting and sizing conversations, then confirm against your own set's data sheet or measured litres per hour before committing to a number in a contract or business case.
How do I measure my generator's real consumption?
- Run the set at a repeatable load for a defined number of hours from a known fuel volume — a calibrated day tank, an installed flow meter, or a measured top-up — and divide litres by hours. Record load, ambient temperature and fuel batch. Repeat over several runs. A single hour of unmatched running is not a measurement.
Does hydrogen enhancement change these figures?
- This page makes no claim about that. The chart exists so you can establish your own baseline first. Any change from a combustion-enhancement system has to be measured on your set, against a matched load and the same fuel, over enough hours to clear normal variation. Published studies report effects that vary with operating point rather than a single uniform figure.
Which HydroHub unit suits a generator set?
- Units are sized by engine displacement, not kW rating. Under 4.5 L the H-Power range covers most small and mid sets; from 7.0 to 16.0 L the DH-Power flagship applies. Two sets with the same kW rating can carry different engines, so size on swept volume.
Where these sets actually run.
Camp and prime power on mine and drilling sites, irrigation pump sets on farm, ship's service sets at sea — the same chart, very different load profiles.
Generator sets →
Stationary diesel gensets on continuous and prime duty from 100–500 kVA — remote camps, telecom sites and standby plant fed from the set's own starting battery.
Mining fleets →
Haul trucks, articulated dumpers, production dozers, loaders, drill rigs and camp gensets. Dust, pit heat and remote servicing decide as much as displacement does, and carted fuel changes what a percentage is worth.
Drilling rigs →
Rig power packs, mud pumps, air compressors and pad plant running long steady-state hours where fuel is trucked in and every litre carries a freight cost.
Agriculture →
Tractors, headers, sprayers, farm trucks and irrigation pump sets. Seasonal idle periods, on-farm water quality and distance from a dealer shape the specification.
All applications — the full vertical index →·Partner program →
Continue reading.
Hydrogen combustion enhancement
What it is, how PEM gas reaches the cylinder, and what it does not do.
Engine performance improvement
Flame speed, burn completeness and load response on diesel engines.
Fuel efficiency
How to baseline and measure litres per 100 km or litres per hour.
Emissions reduction
Soot, particulate and unburnt-fuel behaviour, and how to test it.
Visible smoke reduction
Smoke opacity findings per study, with the NOx trade-off disclosed.
Remote-site fuel logistics cost
Landed cost versus pump price, and why the same percentage moves more money.
Generator-set classes
Camp, prime, standby, rental, telecom, irrigation and ship's service sets compared.
Idle & part-load duty cycles
Reefers, camp gensets and high-idle plant — where the literature reports most room.
Hydrogen with biodiesel blends
Per-study findings for hydrogen enrichment on biodiesel, NOx disclosed.
Installation guide
Nine-step fitting sequence: mounting, wiring, gas line, commissioning.
Safety & compliance
On-demand gas, no storage, alarms, shutdowns and reversibility.
Troubleshooting
Alarms, low gas output, water quality and no-start diagnostics.
Case studies & field results
Published operator data and trial methodology.
Compare PEM systems
A-450 to DH-Power side by side: displacement, output, current draw.
Does it actually work? Evidence review
The published literature, the FTC/EPA history and the ACL context.
How it works
Gas path and established physics, explained with diagrams.
PEM vs alkaline
Membrane on water versus caustic KOH: servicing, purity, cost.
Sizing combined gas
Why PEM and alkaline gas-volume benchmarks are not interchangeable for ICE sizing.
Four hydrogen technologies
Enhancement vs H2ICE vs fuel cell vs chemical generation.
Compared with Hydrogen Fuel Systems
Honest comparison with the Perth-based Gen alkaline range.
Compared with H2i Technology
Hardware, pricing and evidence transparency versus the Victorian supplier.
Compared with dynaCERT HydraGEN
PEM versus alkaline, published price versus dealer quote, Verra versus ACCU.
Compared with HYDI
The South Australian manufacturer: UniSA testing, field history and quote path.
AU installation, warranty & safety
VSB 14 and VSB 6, ACL guarantees and documentation to keep.
Mining fleets
Haul trucks, dozers, drill rigs and site gensets: unit selection and dust.
Marine
Workboats, charter, fishing and ship's service gensets — no gas stored aboard.
Agriculture
Tractors, headers, pump sets and farm trucks across seasonal duty.
FAQ
Answers on fitment, water, warranty, freight and duty cycles.