Generator Fuel Consumption Calculator
Calculate Smarter. Work Faster.
Free generator fuel consumption calculator for diesel gensets — enter maximum load, running time, load profile and unit rating to get total fuel in liters or gallons, average L/kWh, fuel cost and CO₂, with a pie chart of fuel use by load step.
Generator Fuel Consumption Details
Describe the site demand, how long the gensets run and how the load changes over that time.
Demand and run duration
The highest demand the gensets together must carry.
Genset selection
kVA sizes are taken at 0.8 power factor. For long runs, enter the prime (PRP) figure, not standby.
Headroom kept above peak load. It decides how many gensets must be online.
Operating pattern
How the run duration splits across load levels (as % of peak).
Units and price
Advanced settings
Fuel rate of one unit at each % of its own rating, in L/h, from the manufacturer's data sheet for your frequency.
Every unit kept online: time at 0% load burns no-load (idle) fuel. Start/stop keeps online only the gensets each load level needs, with the same headroom, and stops all units at 0% load.
Enter values and hit calculate
Enter values above to see a breakdown.
Keeps your operating pattern, headroom and load sharing, but always uses a generic estimated fuel curve for every size; manufacturer data entered above applies only to your selected genset size. It shows the effect of unit loading, not differences between engine models. Lowest fuel use does not necessarily mean the best system design: redundancy, load acceptance, capital cost and operating requirements also matter.
Enter values above to compare sizes.
How Generator Fuel Consumption Is Calculated
A diesel generator converts fuel energy into electrical output, and like any real energy conversion process, does so with less than 100% efficiency — specific fuel consumption (SFC) captures this efficiency as a practical, directly usable figure: liters of fuel burned per kWh of electrical energy produced. Multiplying SFC by load gives fuel consumption rate; multiplying that rate by run duration gives total fuel consumed. Because SFC changes with load, this calculator repeats that step for every part of the load profile and adds the results.
Formula used: for each load step, Fuel Rate (L/h) = number of running units × fuel rate of one unit at its share of the load; Fuel at that step = Fuel Rate × hours at that step; Total Fuel = the sum of all steps. With the built-in estimate, one unit's fuel rate is F = a × Prated + b × Pout. The typical curve uses a = 0.0533 and b = 0.2467 L/kWh, which gives about 0.30 L/kWh at full load and 0.46 L/kWh at 25% load. The fixed term (a × Prated) represents the no-load component of this simplified fuel-rate model; it is why estimated SFC becomes worse at light load. It is an empirical fit, not a measured idle consumption for any particular engine. In Advanced mode you can replace this estimate with the fuel rates from your generator's data sheet.
Single-point worked example: a generator runs at 200 kW load with an SFC of 0.32 L/kWh for 8 hours. Fuel Consumption Rate = 0.32 × 200 = 64 L/hr. Total Fuel Used = 64 × 8 = 512 L (about 135 US gal). Over this 8-hour period, the generator also produces 200 × 8 = 1,600 kWh of electrical energy, so the same 512 L of fuel can be expressed as roughly 0.32 L per kWh produced — consistent with the SFC figure used, as expected.
Where SFC values come from: generator manufacturers publish fuel consumption curves (or tables) showing SFC or absolute fuel consumption rate at several standard load percentages (commonly 25%, 50%, 75%, and 100% of rated capacity) for each specific genset model — using the SFC value corresponding to your actual expected operating load, not just the 100%-load figure, is important for an accurate estimate, since SFC changes meaningfully across the load range.
Why total fuel isn't simply proportional to rated generator size: a larger generator running at a given kW load doesn't necessarily consume more fuel than a smaller generator delivering the identical kW load — what matters for fuel consumption is the actual kW output and the specific engine's SFC characteristic at that output level, not the generator's overall rated capacity. This is precisely why running a generator well below its rated capacity is fuel-inefficient on a per-kWh basis: you're paying (in fuel) for that generator's fixed losses while extracting comparatively little useful output relative to what the same fixed losses would support at a higher load.
Practical implications for genset sizing decisions: a common tension in generator sizing exists between providing adequate margin for future load growth or occasional peak demand, and avoiding chronic underloading that hurts fuel efficiency during normal, typical operation. One practical approach some facilities use is a multi-generator arrangement (two or more smaller units running in parallel, synchronized to share load) rather than a single large unit — this allows running only as many units as needed to keep each one reasonably loaded during typical operation, while still providing adequate total capacity for peak or future demand by bringing additional units online only when actually needed. The size comparison table under the results shows this effect for your own load profile.
Fuel cost estimation beyond just consumption volume: once total fuel consumption is calculated, multiplying by the fuel price per liter or per gallon, in your local currency, gives estimated fuel cost for a given operating scenario — useful for budgeting planned generator runtime (scheduled maintenance testing, planned load shifting) or for evaluating the total cost of ownership trade-off between generator capital cost and expected ongoing fuel expense across different sizing or technology options being considered for a new installation.
Emissions considerations linked to fuel consumption: since diesel combustion produces CO₂ in proportion to the carbon in the fuel burned, fuel consumption calculations also serve as a reasonable basis for estimating a generator's CO₂ output for a given operating scenario — the calculator converts liters to kilograms with the fuel density and multiplies by a CO₂ factor per kilogram of fuel. Facilities subject to emissions reporting requirements, or simply tracking their carbon footprint, often use fuel consumption data (converted using standard emission factors for diesel combustion) as the basis for this reporting. Other pollutants such as NOx and particulates depend heavily on the engine's emission certification and aftertreatment, so they are not estimated here.
Summary: use Fuel Rate = SFC × Load and Total Fuel = Rate × Duration for a single operating point, split real operation into load steps with the right number of running units, remember that fuel efficiency degrades at partial load, and use consumption estimates as one input into broader fuel storage planning, cost budgeting, and emissions reporting rather than a standalone final answer. For related sizing and power tools, see the electrical calculators collection.
Load bank testing and its relationship to fuel consumption verification: facilities that periodically test their standby generators under simulated load (using a resistive load bank, rather than relying only on lightly-loaded no-load testing) get the added benefit of real-world fuel consumption data at a known, controlled load level — comparing this actual measured consumption against manufacturer-published SFC curves for that load level is a useful way to verify the generator is performing as expected, and to catch a developing engine efficiency problem (worn injectors, air filter restriction, or other maintenance issues) before it becomes a more serious reliability concern during an actual emergency use.
Seasonal and ambient temperature effects on fuel consumption: engine efficiency, and therefore fuel consumption, can vary somewhat with ambient temperature and altitude, similar to the derating effects discussed for other electrical equipment — a generator's published SFC figures are typically referenced to standard conditions, and facilities operating in consistently hot, cold, or high-altitude environments may see somewhat different real-world fuel consumption than the reference figures suggest, another reason why comparing actual measured consumption (from load bank testing or genuine emergency operation) against reference figures periodically is valuable practice.
Whether you're planning fuel storage for a critical backup power installation, budgeting operating costs for a planned maintenance test schedule, or simply trying to understand why a generator seems to burn more fuel than expected during light-load operation, the specific fuel consumption relationship covered here — and its variation with load — is the foundational concept behind all of these practical questions.
Worked Example (calculator defaults)
800 kW maximum load, 625 kVA (500 kW) units, 5% margin, 24 h: 25% of the time at 100% load, 50% at 50% load and 25% at 25% load. Units = ⌈800 × 1.05 ÷ 500⌉ = 2. With both units running all day (typical curve): 1,504 + 1,824 + 616 = 3,944 L for 10,800 kWh, or 0.365 L/kWh. With start/stop by load, one unit covers the 50% and 25% steps: 1,504 + 1,504 + 456 = 3,464 L, or 0.321 L/kWh. At 0.84 kg/L and 3.19 kg CO₂/kg, the all-units case is about 3.31 t of fuel and 10.57 t of CO₂.
The built-in fuel curves are generic estimates, not data for any specific generator model. Fuel consumption varies by make, model, engine technology, frequency version, and condition, so use the manufacturer's published fuel consumption table in Advanced mode wherever you have it. Check the manufacturer's minimum recommended load guidance to avoid wet stacking risk from chronic light-load operation, and periodically validate published figures against actual measured consumption during testing.
Load Profile, Power Margin and Running Several Generators
Real sites rarely sit at one load for the whole run. The load profile tells the calculator what share of the running time is spent at 0, 10, 25, 50, 75 and 100% of the maximum load. A building on backup power may stay near a steady fraction of its peak, while a remote camp can swing between a low night load and a short evening peak. The shares must add up to 100%, and the hours at each step are the running time multiplied by that step's share. The presets marked "example" are starting points, not measured profiles; replace them with logged load data when you have it.
Units and power margin: Units at maximum load = ⌈Maximum load × (1 + power margin) ÷ rating per unit⌉, and maximum load per unit = maximum load ÷ (units × rating). The margin represents spare capacity above the expected peak; depending on the design, additional capacity may also be required for motor starting, load transients or a unit outage, which this margin alone does not guarantee. Extra running capacity also burns fuel at light load, so the margin has a fuel cost as well as a capital cost.
All units running vs start/stop by load: with all units running, every generator stays online for the whole period and shares the load equally, so their fixed no-load fuel is paid for every hour. With start/stop by load, only as many units as each step needs (including the margin) are online, which keeps each running unit more heavily loaded. Start/stop needs paralleling controls, load sharing and enough spare capacity for sudden load steps, so treat it as a design option to evaluate rather than a free saving. The two modes also treat the 0% load level differently: with every unit kept online, time at 0% is no-load (idle) running and its fuel is included; with start/stop, 0% load means all units are stopped and no fuel is counted.
Which rating to enter: ISO 8528-1 defines several generator set power ratings, including emergency standby power (ESP) for limited hours during a supply outage, prime running power (PRP) for unlimited hours at variable load, and continuous operating power (COP) for unlimited hours at constant load. For long or repeated runs, enter the prime or continuous rating rather than the standby figure, and check the manufacturer's data for the exact running-hour and average-load limits of each rating.
| Load level (800 kW peak) | Hours | Every unit kept online | Start/stop to match load |
|---|---|---|---|
| 100% (800 kW) | 6 | 2 units at 80% — 1,504 L | 2 units at 80% — 1,504 L |
| 50% (400 kW) | 12 | 2 units at 40% — 1,824 L | 1 unit at 80% — 1,504 L |
| 25% (200 kW) | 6 | 2 units at 20% — 616 L | 1 unit at 40% — 456 L |
| Total (10,800 kWh) | 24 | 3,944 L (0.365 L/kWh) | 3,464 L (0.321 L/kWh) |
In this example, start/stop uses about 480 L (roughly 12%) less fuel for the same 10,800 kWh because the second engine is not idling through the low-load hours. The all-units case also leaves each unit at 20% load for six hours, below the 30–40% range many manufacturers suggest as a minimum for sustained running, which the calculator flags as a warning. Values use the typical estimated curve with 625 kVA (500 kW) units.
Why Diesel Generators Are Least Fuel-Efficient at Low Load
| Load (% of Rated Capacity) | Typical SFC (L/kWh) | Typical SFC (US gal/kWh) |
|---|---|---|
| 25% | 0.40-0.50 | 0.106-0.132 |
| 50% | 0.33-0.38 | 0.087-0.100 |
| 75% | 0.30-0.34 | 0.079-0.090 |
| 100% | 0.28-0.32 | 0.074-0.085 |
These are general illustrative ranges — exact SFC figures vary by generator make, model, engine technology, and age/maintenance condition, so always reference the specific manufacturer's published fuel consumption curve for your actual generator model rather than these general ranges for a precise calculation. The clear trend, however, is consistent across virtually all diesel gensets: fuel efficiency (lower SFC) improves as load increases toward rated capacity.
It's also worth noting that many diesel engine manufacturers recommend a minimum load level (often around 30-40% of rated capacity) even for generators that will spend most of their time lightly loaded, specifically to avoid a phenomenon called "wet stacking" — incomplete combustion at very low, sustained light load that can cause unburned fuel and carbon deposits to accumulate in the exhaust system over time, potentially leading to engine damage or reduced reliability. This is a separate but related reason (beyond pure fuel efficiency) that chronic very-low-load generator operation is generally avoided in good operating practice.
Diesel Generator Fuel Consumption Chart by Size (Estimated)
The chart below uses the calculator's typical estimated curve for a single unit running on its own, with kVA ratings converted to kW at 0.8 power factor. It is a planning reference, not manufacturer data: the calculator's efficient and small/older estimates sit about 13% below and 17% above these values, and real data sheets can differ further.
| Genset rating | 25% load (L/h) | 50% load (L/h) | 75% load (L/h) | 100% load (L/h) | 100% load (US gal/h) |
|---|---|---|---|---|---|
| 20 kVA (16 kW) | 1.8 | 2.8 | 3.8 | 4.8 | 1.3 |
| 50 kVA (40 kW) | 4.6 | 7.1 | 9.5 | 12.0 | 3.2 |
| 100 kVA (80 kW) | 9.2 | 14.1 | 19.1 | 24.0 | 6.3 |
| 200 kVA (160 kW) | 18.4 | 28.3 | 38.1 | 48.0 | 12.7 |
| 250 kVA (200 kW) | 23.0 | 35.3 | 47.7 | 60.0 | 15.9 |
| 500 kVA (400 kW) | 46.0 | 70.7 | 95.3 | 120.0 | 31.7 |
| 750 kVA (600 kW) | 69.0 | 106.0 | 143.0 | 180.0 | 47.6 |
| 1,000 kVA (800 kW) | 92.0 | 141.3 | 190.7 | 240.0 | 63.4 |
| 1,250 kVA (1,000 kW) | 115.0 | 176.7 | 238.3 | 300.0 | 79.3 |
| 1,500 kVA (1,200 kW) | 138.0 | 212.0 | 286.0 | 360.0 | 95.1 |
| 2,000 kVA (1,600 kW) | 184.0 | 282.7 | 381.3 | 480.0 | 126.8 |
| 2,500 kVA (2,000 kW) | 230.0 | 353.3 | 476.7 | 600.0 | 158.5 |
Why a quarter load is not a quarter of the fuel: with this curve, a generator at 25% load burns about 38% of its full-load fuel rate, at 50% load about 59%, and at 75% load about 79%. The fixed no-load component of this simplified model is the reason, and it is also why the estimated kWh per liter falls as load drops.
Quick mental estimate: near full load, liters per hour ≈ 0.3 × kW output, or US gallons per hour ≈ 0.08 × kW output. At partial load, add the model's no-load component (about 0.053 × rated kW in L/h with the typical curve) instead of scaling the full-load figure down in proportion.
Units, Fuel Specs, CO₂ and Emission Rules by Region
The fuel an engine burns per kWh does not change at a border, but the units people quote, the fuel specifications and the emission rules for new generators do. The calculator lets you work in liters, US gallons or imperial gallons, in any of 15 currencies, and with a fuel density matched to your supply.
Liters, US gallons and imperial gallons
1 US gallon = 3.785 L and 1 imperial gallon = 4.546 L, so the two gallons differ by about 20%. US data sheets usually quote gal/h, while most other markets quote L/h. When you change the volume unit in the calculator, the fuel price and any data-sheet fuel rates you entered are converted with it, so the underlying values stay the same.
Fuel density and CO₂
Density turns liters into kilograms. EN 590, the diesel specification used across Europe and adopted in many other markets, sets 820–845 kg/m³ at 15 °C for most climate classes (0.820–0.845 kg/L). ASTM D975 in the United States does not set a density limit, and typical diesel there is often around 0.83–0.86 kg/L. Diesel density also falls slightly as fuel temperature rises, so a tank's mass of fuel is slightly lower on a hot day for the same volume.
For CO₂, the calculator multiplies fuel mass by about 3.19 kg CO₂ per kg of diesel, which follows from the IPCC 2006 default factor of 74,100 kg CO₂ per TJ and a net calorific value of 43.0 MJ/kg. At 0.84 kg/L that is about 2.68 kg CO₂ per liter. The US EPA GHG Emission Factors Hub lists about 10.21 kg CO₂ per US gallon of diesel, roughly 2.70 kg per liter. Both are tailpipe CO₂ figures; your reporting scheme may require its own factor or CO₂-equivalent values, which you can enter in Advanced mode.
| Region | Diesel specification | Emission rules for new gensets (examples) | Common volume unit |
|---|---|---|---|
| European Union | EN 590 (820–845 kg/m³ at 15 °C, most classes) | EU Stage V under Regulation (EU) 2016/1628 for non-road engines, including many mobile gensets; stationary plants follow other EU and national rules | Liters |
| United States | ASTM D975 (no density limit) | EPA NSPS 40 CFR 60 Subpart IIII for stationary diesel engines: Tier 4 Final for most new non-emergency engines, less stringent tiers for emergency standby engines; some states are stricter | US gallons |
| India | IS 1460 (check the current edition for limits) | CPCB IV+ for diesel gensets up to 800 kW, applicable since July 2023 | Liters |
| Other markets | National standards, often based on EN 590 | National rules or site permits; confirm with the local authority | Mostly liters |
Emission rules decide which engines can be sold or permitted, and aftertreatment such as SCR and particulate filters can change auxiliary loads and consumables, but the fuel estimate itself still depends on output and the engine's fuel curve. Regulations change and have exemptions, so treat this table as orientation and confirm the current requirement for your site.
50 Hz vs 60 Hz generators
For a 4-pole alternator, synchronous speed is typically 1,500 rpm at 50 Hz and 1,800 rpm at 60 Hz. The applicable generator rating and fuel-consumption data can differ between frequency versions, depending on the engine, turbocharging and the manufacturer's design, so use the manufacturer's data for the actual 50 Hz or 60 Hz model you are evaluating.
Other generator fuels
The built-in curves are for diesel gensets only. Petrol (gasoline), propane and natural-gas generators require fuel-specific consumption data, often expressed as gas volume or energy per hour for gaseous fuels, so use the manufacturer's published figures for those fuels.
Common Mistakes When Calculating Generator Fuel Consumption
1. Using 100%-load SFC for a generator that actually runs at a lower partial load. SFC is meaningfully worse at partial load — using the best-case, full-load SFC figure for a facility that typically only reaches 40-50% load during outages understates real fuel consumption.
2. Assuming total fuel consumption scales linearly with generator size rather than actual load. Fuel consumption depends on actual kW output and that specific engine's SFC at that output, not directly on the generator's overall rated capacity — two generators of different sizes delivering the identical kW load consume similar fuel if their SFC at that load point is similar.
3. Ignoring idle/no-load fuel consumption for testing or standby periods. A generator idling with no electrical load still burns fuel — include that time at the 0% load level with every unit kept online if periodic testing or extended standby idling represents meaningful operating time for your application.
4. Not accounting for fuel quality or altitude effects on actual consumption. Manufacturer SFC figures are typically published for standard fuel quality and sea-level (or specified reference altitude) conditions — significant deviations from these reference conditions can shift actual fuel consumption from the published figures.
5. Sizing fuel storage based only on consumption rate without considering maximum realistic outage duration and refueling logistics. Fuel consumption calculation is one input to a broader fuel storage planning exercise — it doesn't by itself determine how much on-site fuel storage capacity is actually needed for your specific outage risk profile and refueling logistics constraints.
6. Running an oversized generator well below its efficient load range as routine practice. A generator significantly oversized relative to actual typical load runs persistently in its least fuel-efficient operating range — right-sizing generator capacity to actual expected load (with reasonable, not excessive, margin) improves real-world fuel economy over the equipment's service life.
7. Ignoring the wet stacking risk from chronic very-low-load operation. Sustained running well below roughly 30-40% of rated capacity can cause incomplete combustion and carbon buildup over time, a reliability concern separate from pure fuel efficiency — check manufacturer minimum recommended load guidance, not just fuel cost, when planning chronic light-load operation.
8. Never validating published SFC figures against actual measured consumption. Real-world fuel consumption can drift from manufacturer reference figures due to ambient conditions, fuel quality, or developing maintenance issues — periodic load bank testing with fuel consumption measurement helps catch this drift before it becomes a reliability concern.
9. Entering the standby (ESP) rating for long, variable-load running. The standby rating is meant for limited hours during outages. Using that larger figure as the per-unit capacity for prime or continuous duty overstates what each unit can carry, understates the load per unit and can hide the need for another unit.
10. Mixing US gallons, imperial gallons and liters. Mixing liters, US gallons and imperial gallons can create large errors — for example, 1 US gal is 3.785 L while 1 imp gal is 4.546 L. Pick one volume unit in the calculator and let it convert prices and data-sheet values for you.
Frequently Asked Questions
What is the formula for generator fuel consumption? +
For a single operating point, Fuel Consumption Rate (L/h) = Specific Fuel Consumption (L/kWh) × Load (kW), and Total Fuel Used = Fuel Consumption Rate × Operating Duration (h). Because specific fuel consumption changes with load, this calculator splits the running time into load steps (0, 10, 25, 50, 75 and 100% of maximum load), works out the fuel rate of the running units at each step, multiplies it by the hours spent there and adds the steps together.
What is a typical specific fuel consumption (SFC) value for a diesel generator? +
Near full load, many diesel gensets fall roughly between 0.25 and 0.35 L/kWh (about 0.066 to 0.092 US gal/kWh), with large modern engines toward the lower end and small or older units toward the higher end. SFC rises noticeably at partial load, so use a figure that matches your actual operating load, ideally from the manufacturer's fuel consumption table, rather than a single generic average.
Why does a generator use more fuel per kWh at low load than at high load? +
A diesel engine has certain fixed losses (friction, driving auxiliary systems, maintaining idle combustion) that don't scale down proportionally with reduced electrical output — at low load, these fixed losses represent a larger fraction of total fuel burned relative to the smaller amount of useful electrical energy produced, making fuel consumption per kWh (SFC) worse at low load than at high load, where the same fixed losses are spread over much more useful output.
Is it more economical to run one large generator at partial load, or a smaller generator near full load? +
Generally, running a generator closer to its rated capacity (typically 70-100% load) gives better fuel efficiency (lower SFC) than running it lightly loaded — this is one of several reasons facilities with variable backup power needs sometimes use multiple smaller generators, running only as many as needed to keep each one reasonably loaded, rather than one large generator running mostly at low partial load.
How do I estimate fuel consumption for a facility's typical backup power scenario? +
Estimate the facility's actual expected load during an outage rather than the generator's full rated capacity, describe how many hours it spends at each load level, then apply the fuel consumption at each level (manufacturer data where available) and add the results. The load profile inputs in this calculator do exactly that. Using full-load SFC for a site that actually runs at a lower partial load during outages will understate real fuel consumption.
Does fuel consumption scale linearly with load, or is the relationship more complex? +
The relationship between load and fuel consumption rate (L/hr) is roughly linear across much of the operating range for most diesel engines, but SFC (L/kWh, fuel per unit of output) is not constant across load — it's worse at low load and improves toward higher load, meaning total fuel burned isn't simply proportional to load in the way a perfectly linear, constant-efficiency device would suggest. This calculator uses a simplified linear fuel-rate model for its built-in estimates; actual engine fuel curves can deviate from this relationship.
Why is fuel storage sizing important beyond just calculating consumption rate? +
Beyond simply knowing how much fuel a generator burns per hour, facilities need adequate on-site fuel storage to cover the maximum realistic outage duration they need to plan for, plus a safety margin, and often need to account for fuel delivery lead time if extended outages are a genuine risk — fuel consumption calculation is the starting input for this broader fuel storage and refueling logistics planning, not the complete answer on its own.
Does this calculator account for fuel used during no-load or idle operation? +
It depends on the load-sharing mode. With every unit kept online, time assigned to the 0% load level is treated as no-load (idle) running and its fuel is included, using the no-load component of the estimated curve, or a value extrapolated from the 25% and 50% points in manufacturer-data mode, so treat it as approximate. With start/stop to match load, 0% load is treated as all units stopped, so no fuel is counted. If idling matters for your application, use a measured or manufacturer idle figure where you have one.
How does fuel quality or altitude affect generator fuel consumption? +
Lower fuel quality (lower energy content per liter) can increase the volume of fuel needed for the same electrical output, and high-altitude operation can reduce a naturally aspirated diesel engine's power output and efficiency due to reduced air density (though many modern generators use turbocharging to substantially compensate for this effect) — both factors can shift actual fuel consumption away from a manufacturer's standard-condition published SFC figures.
How much diesel does a generator use per hour at full load? +
A rough planning figure is 0.25 to 0.30 L per kWh of output near full load. With the typical estimate used on this page, a 500 kVA (400 kW) generator at full load uses about 120 L/h (roughly 32 US gal/h), and a 1,000 kVA (800 kW) unit about 240 L/h (roughly 63 US gal/h). Real values depend on the engine model, so check the manufacturer's data sheet before sizing fuel tanks.
What is power margin and how does it change the number of units running? +
Power margin is spare capacity kept above the maximum load. The calculator finds the units needed at maximum load as Units = ⌈Maximum load × (1 + margin) ÷ rating per unit⌉. A larger margin can add a unit, which lowers the load on each unit and raises fuel use if all units keep running, so take the margin from your design criteria rather than making it as large as possible.
How much CO₂ does burning one liter or one US gallon of diesel produce? +
If all the carbon in the fuel is converted to CO₂, one liter of diesel at 0.84 kg/L produces roughly 2.68 kg of CO₂ using a factor of about 3.19 kg CO₂ per kg of fuel. The US EPA GHG Emission Factors Hub lists about 10.21 kg CO₂ per US gallon of diesel, which is roughly 2.70 kg per liter. These are tailpipe CO₂ figures, not life-cycle or CO₂-equivalent values.
Does a 50 Hz or 60 Hz generator use a different amount of fuel? +
For a 4-pole alternator, synchronous speed is typically 1,500 rpm at 50 Hz and 1,800 rpm at 60 Hz. The applicable generator rating and fuel-consumption data can differ between frequency versions, so use the manufacturer's data for the actual 50 Hz or 60 Hz model rather than assuming one version's figures apply to the other.
Can I use this calculator for petrol (gasoline), propane or natural gas generators? +
The built-in curves are for diesel gensets only. Petrol, propane and natural-gas generators require fuel-specific consumption data, so use the manufacturer's published figures for those fuels.